Silicon Laboratories Si475X Series, Si475x-A40, Si475x-A30, Si475x-A55, Si475xC-A55 Programming Manual

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AN543

Si475X PROGRAMMING GUIDE

1. Introduction

This document provides an overview of the programming requirements for the Si475x-A10/A20/A30/A40/A55 and Si475xC-A55 AM/FM receiver. The hardware control interface and software commands are detailed along with several examples of the required steps to configure the device for various modes of operation. Table 1 provides a programming guide cross-reference for each Si475x part released by Silicon Labs to date. This programming guide focuses on the Si475x/5xC-A55 release; however, features, properties, ranges, and defaults that differ from the Si475x-A10 to Si475x-A40 are noted as well. Refer to previous versions of this document for earlier firmware revisions.

Table 1. Si475x Firmware Revisions

Part # Part Revision FMRX Component AMRX Component

Si475x-A10 1.0 3.2.3 3.2.3

Si475x-A20 2.0 8.0.8 7.0.5

Si475x-A30 3.0 10.0.8 9.0.6

Si475x-A40 4.0 13.0.11 12.0.10

Si475x-A55 5.5 15.0.2 14.0.1

Si475xC-A55 5.5 15.0.2 14.0.1

2. Overview

This devices in this product family are programmed using commands and responses. To perform an action, the system controller writes a command byte and associated arguments, which cause the device to execute the given command. The device will, in turn, provide a response depending on the type of command that was sent.

The device has a slave control interface that allows the system controller to send commands to and receive

responses from the device using 2-wire mode (I

C compatible).

3. Terminology

 CTS—Clear to send  STC—Seek/Tune Complete  NVM—Non-volatile internal device memory  Device—Refers to the AM/FM Receiver  System Controlle r —Refers to the system microcontroller  CMD—Command byte  ARGn—Argument byte (n = 1 to 7)  STATUS—Status byte  RESPn—Response byte (n = 1 to 15)

Silicon Laboratories Confidential. Information contained herein is covered under non-disclosure agreement (NDA).

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AN543

SCL

70%

30%

SDA

70%

30%

START

STARTSTOP

f:IN

r:IN

LOW

HIGH

HD:STA

SU:STA

SU:STO

BUF

SU:DAT

r:IN

HD:DAT

f:IN,

f:OUT

PD:DAT

SCL

SDA

(Write)

START STOPADDRESS + R/W ACK DATA ACK DATA ACK

A6-A0, 0

Command

7-0

Arg1

7-0

SDA

(Read)

START STOPADDRESS + R/W ACK DATA ACK DATA ACK

A6-A0, 1

Status

7-0

Response

7-0

4. Control Interface

The Si475x provides an I2C-compatible, 2-wire control interface.

In powerdown mode, all circuitry is disabled except for the device control interface. The device comes out of powerdown mode when the POWER_UP command is written to the command register. Once in powerup mode, the device accepts additional commands such as tuning. The device will not accept commands while in

powerdown mode, with the exception of the powerup command. If the system controller writes a command other

than POWER_UP when in powerdown mode, the device does not respond, and the command is ignored.

Setting the RSTB pin low places the device in reset mode. In reset mode, all circuitry is disabled including the device control interface; registers are set to their default settings, and the control bus is disabled.

4.1. 2-Wire Control Interface

Figure 1 and Figure 2 show the 2-wire control interface read and write timing parameters and diagrams, respectively. Refer to the Si475x data sheet for timing parameter values.

Figure 1. I2C Control Interface Read and Write Timing Parameters

2 Rev. 0.9

Figure 2. I

C Control Interface Read and Write Timing Diagram

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Two-wire bus mode uses the SCL and SDA pins for signaling. A transaction begins with the START condition, which occurs when SDA falls while SCL is high. Next, the system controller drives an 8-bit control word serially on SDA, which is captured by the device on rising edges of SCL. The control word consists of a seven-bit device address followed by a read/write bit (read = 1, write = 0). The device acknowledges the control word by driving SDA low on the next falling edge of SCL.

For write operations, the system controller next sends a data byte on SDA, which is captured by the device on rising edges of SCL. The device acknowledges each data byte by driving SDA low for one cycle on the next falling edge of SCL. For each write transaction, the first byte is a command and the following bytes are arguments.

For read operations, after the device has acknowledged the control byte, it will drive an eight-bit data byte on SDA, changing the state of SDA on the falling edges of SCL. The system controller acknowledges each data byte by driving SDA low for one cycle on the next falling edge of SCL. If a data byte is not acknowledged by the system controller, the transaction will end. For each read transaction, the first byte is the status byte and the following bytes are the response data from the receiver.

A 2-wire transaction ends with the STOP condition, which occurs when SDA rises while SCL is high.

5. Powerup and Powerdown

There are two procedures for powering up a receiver to move it from powerdown mode to the powerup mode. The first is a powerup from internal receiver memory. The second is a powerup from a firmware component patch that is stored in system controller memory. Patches can be applied to a firmware component by the system controller via a download mechanism to address field issues, errata, or adjust device behavior. Patches are encrypted and unique to a particular device firmware version, cannot be generated by customers, and can be used to replace a portion of the component (to address errata, for example) or to download an entirely new component. The user must verify that the device contains the correct base firmware to support the patch as described later in this section.

It has been noted that some crystals require greater startup current and settling times than others. The procedure below is meant to apply to a wide variety of such crystals, providing maximum current and 40 ms for crystal oscillation to stabilize. If there are still difficulties with POWER-UP that may be related to your choice of crystal, please refer to the settings and hardware options in “AN750: Si475x 4 MHz Crystal Compatibility Power-Up Procedure”.

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AN543

Supply VA, VD, and VIO while

keeping the RSTB = 0

START

After a minimum of 100 µs,

set RSTB = 1

After a minimum of 100 µs,

continue to the next step

Send second POWER_UP

command for the desired

function (AM, FM)

Commence normal operation

Send POWER_DOWN

command

Send the POWER_UP

command for desired function

(AM, FM)

Wait at least 100 ms

Send command

to force CTS = 1

5.1. Powerup Receiver from Internal Memory

1. Supply VA, VD, and VIO while keeping the RSTB = 0. Power supplies may be sequenced in any order.

2. After a minimum of 100 µs, set RSTB = 1.

3. After a minimum of 100 µs, continue to the next step.

4. Send the POWER_UP command for the desired function (AM, FM).

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Example (with crystal 4 MHz, FM function):

1. Provide the initial POWER_UP Command:

Action Data Description

CMD 0x01 POWER_UP

ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal

ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE

Note: Change this value to the capacitance that matches the crystal in use.

ARG3 0x27 SETS CRYSTAL BIAS = 7 w/ FASTBOOT

AN543

ARG4 0x00

0x10 0x20

ARG5 0x00 DIGITAL CORE DISABLED/CRYSTAL OSCILLATOR DISABLED

STATUS NO CTS bit returned

2. Apply a wait time of at least 100 ms.

3. Apply the following command:

Action Data Description

CMD 0xFB CONTROL REGISTER WRITE COMMAND

ARG1 0X06 CONTROL REGISTER ADDRESS

ARG2 0x80 FORCES CTS = 1

STATUS NO CTS bit returned

4. Apply the following command:

Action Data Description

CMD 0x01 POWER_UP

ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal

ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE

ARG3 0x23 SETS CRYSTAL BIAS = 3 w/ FASTBOOT

BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal

Note: Change this value to the capacitance that matches the crystal in use.

ARG4 0x00

0x10 0x20

ARG5 0x11 DIGITAL CORE ENABLED/CRYSTAL OSCILLATOR ENABLED

STATUS CTS = 1

Note: For more details on the external circuit for the 4 MHz crystal, see “AN750: Si475x 4 MHz Crystal Circuit and Power-Up

Procedure”.

5. The device is ready to commence normal operation and accept additional commands. Refer to Figure 3.

BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal

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VIO

RSTB

SCL

SDA

POWER_UP Command

100 µs min

> 10 µs

Figure 3. Powerup Timing

6. If desired, send the POWER_DOWN command.

Example:

POWER_DOWN Command Action Data Description

CMD 0x11 POWER_DOWN

ARG1 0x00 Disable oscillator (ARG1 may be omitted with the same result)

STATUS →0x80 CTS = 1

7. It is now possible to move to the powerup state by returning to step 4.

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5.2. Powerup Receiver from a Patch

Supply V A, V D, and VIO

while keeping the RSTB = 0

START

After a minimum of 100 µs,

set RSTB = 1

After a minimu m of 100 µs,

continue to the next step

Send the POWER_UP

command for the desired

function (AM, FM)

Send POWER_DOWN

command

Verify Firmw are and R OM

revision?

Send PART_INFO command

Wait at least 100 ms

Send second POWER_UP

command for the desired

function (AM, FM)

Send the POWER_UP

command with boot loader

function

Send patch data.

Send the POWER_UP

command for the desired

function (A M, FM )

Commence normal operation.

Send POWER_DOWN

command.

Wait at least 100 ms

Send second POWER_UP

command with bootloader

function

Send comm and to force

CTS = 1

Send command to force

CTS = 1

AN543

1. Supply VA, VD, and VI0 while keeping the RSTB = 0. Power supplies may be sequenced in any order.

2. After a minimum of 100 µs, set RSTB = 1.

3. After a minimum of 100 µs, proceed to the next step.

4. (Optional – step 1 of 3 to verify part firmware revision and ROM revision.) Both part firmware revision and ROM revision must be compatible with a partial patch and ROM revision must be compatible with a full patch. Send the POWER_UP command for the desired function (AM, FM).

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Example (with crystal 4 MHz, FM function):

1. Provide the initial POWER_UP Command:

Action Data Description

CMD 0x01 POWER_UP

ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal

ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE

Note: Change this value to the capacitance that matches the crystal in use.

ARG3 0x27 SETS CRYSTAL BIAS = 7 w/ FASTBOOT

ARG4 0x00

0x10 0x20

ARG5 0x00 DIGITAL CORE DISABLED/CRYSTAL OSCILLATOR DISABLED

STATUS NO CTS bit returned

2. Apply a wait time of at least 100 ms.

3. Apply the following command:

Action Data Description

CMD 0xFB CONTROL REGISTER WRITE COMMAND

ARG1 0X06 CONTROL REGISTER ADDRESS

ARG2 0x80 FORCES CTS = 1

STATUS NO CTS bit returned

4. Apply the following command:

Action Data Description

CMD 0x01 POWER_UP

ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal

ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE

ARG3 0x23 SETS CRYSTAL BIAS = 3 w/ FASTBOOT

BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal

Note: Change this value to the capacitance that matches the crystal in use.

ARG4 0x00

0x10 0x20

ARG5 0x11 DIGITAL CORE ENABLED/CRYSTAL OSCILLATOR ENABLED

STATUS CTS = 1

Note: For more details on the external circuit for the 4 MHz crystal, see “AN750: Si475x 4 MHz Crystal Circuit and Power-Up

Procedure”.

5. (Optional – step 2 of 3 to verify part firmware revision and ROM revision). Verify part firmware revision and ROM revision. Send the PART_INFO command.

8 Rev. 0.9

BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal

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AN543

Example:

PART_INFO Command Action Data Description

CMD 0x02 PART_INFO

STATUS →0x80 CTS = 1

RESP1 →0x06 Chip revision, 6

RESP2 →0x35 Part number (last two digits) 0x35 = 53, or Si4753

RESP3 →0x32 Firmware major revision = ASCII character “2”

RESP4 →0x30 Firmware minor revision = ASCII character “0”

RESP5 →0x00 Firmware build version = 0

RESP6 →0x00 Reserved, values will vary

RESP7 →0x00 Reserved, values will vary

RESP8 →0x04 ROM ID

In this example, the part revision is 2.0.0 and the ROM ID is 4. Ensure that partial patches received from Silicon Labs are intended for use with the part firmware revision and ROM, and that full patches are intended for use with the ROM ID as shown in Table 2. It is possible to verify the FM and AM component firmware revisions with the FUNC_INFO command, however, this is not necessary because there is always a unique mapping of component revision to part revision.

Table 2. Si475x Firmware and ROM Compatibility

Part # Part Revision ROM ID FM Revision AM Revision

Si475x-A10 1.0 2 3.2.3 3.2.3

Si475x-A20 2.0 4 8.0.8 7.0.5

Si475x-A30 3.0 5 10.0.8 9.0.6

6. (Optional—step 3 of 3 to verify part firmware revision and ROM revision.) Send the POWER_DOWN command. This step is required before proceeding with the patching procedure if steps 4 and 5 have been followed.

Example

POWER_DOWN Command Action Data Description

CMD 0x11 POWER_DOWN

ARG1 0x00 Disable oscillator (ARG1 may be omitted with the same result)

STATUS →0x80 CTS = 1

7. Send the POWER_UP command for boot loader function.

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Example (with crystal 4 MHz, boot loader function):

1. Provide the initial POWER_UP Command:

Action Data Description

CMD 0x01 POWER_UP

ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal

ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE

Note: Change this value to the capacitance that matches the crystal in use.

ARG3 0x27 SETS CRYSTAL BIAS = 7 w/ FASTBOOT

ARG4 0x00

0x10 0x20

ARG5 0x00 DIGITAL CORE DISABLED/CRYSTAL OSCILLATOR DISABLED

STATUS NO CTS bit returned

2. Apply a wait time of at least 100 ms.

3. Apply the following command:

Action Data Description

BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal

CMD 0xFB CONTROL REGISTER WRITE COMMAND

ARG1 0X06 CONTROL REGISTER ADDRESS

ARG2 0x80 FORCES CTS = 1

STATUS NO CTS bit returned

4. Apply the following command:

Action Data Description

CMD 0x01 POWER_UP

ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal

ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE

Note: Change this value to the capacitance that matches the crystal in use.

ARG3 0x23 SETS CRYSTAL BIAS = 3 w/ FASTBOOT

ARG4 0x00

0x10 0x20

ARG5 0x11 DIGITAL CORE ENABLED/CRYSTAL OSCILLATOR ENABLED

STATUS CTS = 1

5. Send the patch data.

BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal

The patch file provided by Silicon Labs typically has a .sg extension. The system controller must send each line of 8 bytes, wait for a CTS, then send the next line of 8 bytes, etc., until the entire patch has been sent. An example showing the first few lines and final line of a patch file is shown below. Note that the “#” character indicates a comment and the patch file indicates the required ROM ID for a partial or full download. If the checksum fails, the part issues an error code, ERR (bit 6 of the STATUS byte received after each 8-byte transfer), and halts. The part must be reset to recover from this error condition.

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The following is an example of a patch file:

# COPYRIGHT=2011 Silicon Laboratories, Inc.

# GENERATED=13:53 May 23 2011

# ROMID=0x04

# PATCHID=0x228C

# REQUIRES=NONE

# SIZE=8272

# FUNCTION=FMRX

# MAJOR=8

# MINOR=0

# BUILD=8

# CRCT=0x81CF

# CRCM=0x0A6C

# CRCP=0xEC8D

# CRCX=0x66EE

AN543

# CRCY=0x6381

# CRCZ=0xA805

0x04,0x11,0x81,0xCF,0x00,0x00,0x0D,0xC6

0x05,0xAE,0xE1,0xBD,0xB4,0x90,0x07,0x33

0x06,0xD9,0x3D,0x11,0xF7,0x25,0xCB,0x06

0x17,0x7A,0xF8,0xD0,0x71,0x10,0x3F,0xB7

0x1F,0xBF,0xFF,0x7E,0x42,0xE7,0x53,0x05

…

[Additional Lines]

…

0x08,0x21,0xAB,0xB5,0xF1,0x7A,0xD6,0x5A

0x08,0x10,0x0E,0x9E,0x3B,0xD1,0x01,0xF4

0x08,0xBF,0x8D,0x94,0xB0,0x2D,0xCF,0xFF

0x05,0x8D,0xB1,0x22,0xF2,0x8D,0x22,0x8C

# END

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Example:

First line of the patch file example Action Data Description

CMD 0x04

ARG1 0x11

ARG2 0x81

ARG3 0xCF

ARG4 0x00

ARG5 0x00

ARG6 0x0D

ARG7 0xC6

STATUS →0x80 CTS = 1

Second line of the patch file example

CMD 0x05

ARG1 0xAE

ARG2 0xE1

ARG3 0xBD

ARG4 0xB4

ARG5 0x90

ARG6 0x07

ARG7 0x33

STATUS →0x80 CTS = 1

6. Send the POWER_UP command for the desired function (AM, FM).

Example (with crystal 4 MHz, FM function):

POWER_UP Command Action Data Description

CMD 0x01 POWER_UP

ARG1 0x77 Normal operation

ARG2 0x27 Crystal load capacitance = 15.803 pF each pin

ARG3 0x23 Disables CTS interrupt, crystal bias = 3, enable fastboot

ARG4 0x10 FM function, crystal frequency 4 MHz

ARG5 0x11 Crystal

STATUS →0x80 CTS = 1

Example (with external clock 4 MHz, FM function):

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POWER_UP Command Action Data Description

CMD 0x01 POWER_UP

ARG1 0x77 Normal operation

ARG2 0x00 Crystal load capacitance = 5 pF each pin

ARG3 0x23 Disables CTS interrupt, crystal bias = 3, enable fastboot

ARG4 0x10 FM function, clock frequency 4 MHz

ARG5 0x12 External clock

STATUS →0x80 CTS = 1

7. The device is ready to commence normal operation and accept additional commands.

8. If desired, send the POWER_DOWN command.

Example:

POWER_DOWN Command Action Data Description

CMD 0x11 POWER_DOWN

AN543

ARG1 0x00 Disable oscillator (ARG1 may be omitted with the same result)

STATUS →0x80 CTS = 1

9. It is now possible to move to the powerup state by returning to step 7.

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AN543

Command

FM_TUNE_FREQ

Control

Bus

STC

INT

CTS

Bit

STC

Bit

Command

FM_RSQ_STATUS

INTB

CTS

6. Timing

6.1. Command and Property Timing

When the user reads a response over the I2C bus, the first 8 bits returned are the STATUS register. Bit 7 of the STATUS register is the CTS bit (Clear to Send). When CTS is 1, it indicates that the chip is ready to receive a new command. Seek and Tune commands may take longer to complete than most other commands, so they also use the STC bit (Seek/Tune Complete) to indicate they have completed. STC is bit 0 of the STATUS register.

When the user sends any command, the CTS bit will immediately reset to 0. CTS will remain 0 while the chip processes the command. When the chip is finished processing the command, the CTS bit will be set back to 1. Before sending another command, the user may poll CTS by reading the first byte of response until CTS = 1. If the user has enabled the optional CTS interrupt, then the INTB pin will pulse low immediately after CTS has been set to 1, to notify the user that the previous command has completed. For information on how to enable the CTS interrupt, see the INT_CTL_ENABLE property and CTSIEN bit in the arguments for the POWER_UP command.

The commands for seek and tune (FM_TUNE_FREQ, FM_SEEK_START, etc.) will cause CTS to reset to 0 for a short time, but they will set CTS back to 1 after the seek or tune has started. The seek or tune is progressing even though CTS has been set back to 1. Although the user is free to send another command at this time, it is highly recommended to wait until the STC (Seek/Tune Complete) bit has been set to 1 before sending another command. The only exception is the AM/FM_RSQ_STATUS command, which may be sent at any time because it can be used to cancel the seek/tune in progress and check the status of which station seek is currently on.

When the seek/tune completes, the STC bit will be set to 1. The user may poll STC by reading the first byte of response until STC = 1. If the user has enabled the optional STC interrupt, then the INTB pin will pulse low immediately after STC has been set to 1, to notify the user that the seek or tune has completed. For information on how to enable the STC interrupt, see the INT_CTL_ENABLE property.

After the seek or tune has completed, the user may acknowledge the completion by sending the AM/ FM_RSQ_STATUS command with the STCACK bit set to 1. This will reset the STC bit back to 0. After this, the user may send another seek or tune command. Alternatively a new seek or tune command will also clear the STC bit when it begins.

Figure 4 shows a seek or tune command with the optional CTS and STC interrupts enabled. The timing parameters are shown in Table 3.

Figure 4. CTS and STC Timing Model

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Table 3. Command Timing Parameters for Common Commands

FM_SEEK_BAND_TOP FM_SEEK_BAND_BOTTOM–

FM_SEEK_FREQ_SPACING

--------------------------------------------------------------------------------------------------------------------------------------------------









STC



AN543

Command t

CTS

STC

INT

POWER_UP 100ms — 3µs

POWER_DOWN <1000 µs — 3 µs

FUNC_INFO <200 µs — 3 µs

SET_PROPERTY <200 µs — 3 µs

GET_PROPERTY <200 µs — 3 µs

GET_INT_STATUS <200 µs — 3 µs

AGC_STATUS <200 µs — 3 µs

ANA_AUDIO_PIN_CFG <200 µs — 3 µs

Table 4. Command Timing Parameters for FM Receiver

Command t

FM_TUNE_FREQ <200 µs 21 ms 3 µs

FM_TUNE_FREQ (fast tune) <200 µs 5 ms 3 µs

FM_SEEK_START <200 µs See Note below. 3 µs

FM_RSQ_STATUS <200 µs — 3 µs

FM_ACF_STATUS <200 µs — 3 µs

CTS

STC

INT

FM_RDS_STATUS <200 µs — 3 µs

FM_RDS_BLOCKCOUNT <200 µs — 3 µs

*Note: t

is seek time per channel. Total seek time depends on bandwidth, channel spacing, and

STC

number of channels to next valid channel.

Worst case seek time complete for FM_SEEK_START is:

For Si475x-A30, the seek time will require an additional t spacings other than 200 kHz.

STC

+ t

STC(FAST)

for channel

Table 5. Command Timing Parameters for AM Receiver

Command t

AM_TUNE_FREQ 100 µs 40 ms 3 µs

AM_SEEK_START 100 µs See Note below. 3 µs

AM_RSQ_STATUS 100 µs — 3 µs

AM_ACF_STATUS 100 µs — 3 µs

*Note: t

is seek time per channel. Total seek time depends on bandwidth, channel spacing, and

STC

number of channels to next valid channel.

CTS

STC

INT

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AF Tune

command

issued

AF Tune

Initiated

F1 F

AF station metrics qualified:

Above thresholds

Tuner stays on AF station

Audio Audio

}

T1 ~ 0.5 ms T

~ 1 ms

~ 4.8 ms

6.2. Alternate Frequency (AF) Timing

The Si4754/55/56/57 features a flexible FM tune command that allows for a number of operational choices. While tuned to the current station, the receiver can quickly tune to candidate FM stations and perform one of three operations.

1. Tune to the FM station and stay tuned.

2. Tune to the FM station; check the selected signal metrics, and jump back to the original station (AF check).

3. Tune to the FM station; check the selected signal metrics, and decide if the receiver is kept tuned to the FM

station (AF Jump) or re-tuned to the original station.

The timing diagrams for AF tune and AF check are shown in Figure 5 and Figure 6, respectively.

Figure 5. AF Tune Diagram

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AF Check command

issued

AF Check

Initiated

F1 F

2 F1

AF Station metrics

measured and qualified.

Tuner jumps back to F

Audio Audio

}

T1 ~ 0.5 ms T

~ 1 ms

~ 7 ms

Figure 6. AF Check Timing Diagram

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AN543

Fast Tune

command

issued

Fast Tune

Initiated

F1 F

Audio

}

T1 ~ 0.5 ms T

~ 1 ms

6.3. Fast Tune Timing

The timing diagram for fast tune is shown in Figure 7.

Figure 7. Fast Tune Timing Diagram

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7. Commands and Properties

7.1. Common Commands and Properties

The following properties and commands are common to all receiver modes.

Table 6. Common Receiver Command Summary

Number Name Summary

AN543

0x01 POWER_UP

0x02 PART_INFO Returns the part information of the device.

0x11 POWER_DOWN Power-down the device.

0x12 FUNC_INFO Returns the firmware revision and patch revision.

0x13 SET_PROPERTY Sets the value of a property.

0x14 GET_PROPERTY Retrieve a property's value.

0x15 GET_INT_STATUS Read interrupt status bits.

0x17 AGC_STATUS Reports the status of the AGC.

0x1B ANA_AUDIO_PIN_CFG Configures the analog audio pins.

0x1C INTB_PIN_CFG Configures behavior of INTB and A1 pins.

Power-up device and mode selection. Modes include operational function (AM, FM) and audio interface configuration.

Table 7. Common Receiver Property Summary

Number Name Default Summary

A10 A20 A30 A40 A55

0x0000 INT_CTL_ENABLE

0x0300 AUDIO_ANALOG_VOLUME

0x0301 AUDIO_MUTE

0x0000 0x0000 0x0000 0x0000 0x0000

0 0 000

0x003F 0x003F 0x003F 0x003F 0x003F

63 63 63 63 63

0x0000 0x0000 0x0000 0x0000 0x0000

0 0 000

Rev. 0.9 19

Interrupt enable property.

Sets the analog audio volume.

Audio mute property.

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AN543

Table 8. Status Response for the FM Receiver

Bit 76543210

STATUS

Bit Name Function

7CTS

6ERR

5:4 Reserved Values may vary.

3RSQINT

2RDSINT

1ACFINT

0STCINT

CTS ERR XX RSQINT RDSINT ACFINT STCINT

Clear to Send. 0 = Wait before sending next command. 1 = Clear to send next command.

Error. 0=No error. 1=Error.

Received Signal Quality Interrupt. 0 = Received Signal Quality measurement has not been triggered. 1 = Received Signal Quality measurement has been triggered.

Radio Data System Interrupt. 0 = Radio data system interrupt has not been triggered. 1 = Radio data system interrupt has been triggered.

Automatically Controlled Features Interrupt. 0 = ACF measurement has not been triggered. 1 = ACF measurement has been triggered.

Seek/Tune Complete Interrupt. 0 = Tune complete has not been triggered. 1 = Tune complete has been triggered.

20 Rev. 0.9

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Table 9. Status Response for the AM Receiver

Bit 76543210

STATUS

Bit Name Function

7CTS

6ERR

5:4 Reserved Values may vary.

3RSQINT

2 Reserved Value may vary.

CTS ERR XX RSQINT X ACFINT STCINT

Clear to Send. 0 = Wait before sending next command. 1 = Clear to send next command.

Error 0=No error. 1=Error.

Received Signal Quality Interrupt 0 = Received Signal Quality measurement has not been triggered. 1 = Received Signal Quality measurement has been triggered.

Automatically Controlled Features Interrupt.

1ACFINT

0STCINT

0 = ACF measurement has not been triggered. 1 = ACF measurement has been triggered.

Seek/Tune Complete Interrupt. 0 = Tune complete has not been triggered. Do not send a new TUNE/SEEK command. 1 = Tune complete has been triggered. It is safe to send a new TUNE/ SEEK command.

Rev. 0.9 21

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If the ERR bit in the STATUS response is set for a command or property, the response is redefined as follows:

Table 10. Response When ERR Bit is Set

Bit 7 6 5 4 3 2 1 0

STATUS CTS 1 XX RSQINT RDSINT ACFINT STCINT

RESP1 ERROR

RESP Bit Name Function

Error definitions. 0x10 = Bad command. 0x11 = Bad ARG1. 0x12 = Bad ARG2. 0x13 = Bad ARG3.

17:0ERROR

0x14 = Bad ARG4. 0x18 = Command busy. 0x20 = Bad internal memory. 0x30 = Bad patch. 0x31 = Bad boot mode. 0x40 = Bad property.

22 Rev. 0.9

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7.1.1. Common Receiver Commands

Command 0x01 POWER_UP

The POWER_UP command initiates the boot process to move the device from powerdown to powerup mode. The boot can occur from internal device memory or a system controller downloaded patch. This command powers up the device with the specified function (FM Receive and AM Receive). Power-up is complete when the CTS bit is set. This is the only command that may be sent while the device is powered down. Due to variation of the 4 MHz crystal from vendor to vendor, two power up commands are required for reliably powering up: a 4 MHz crystal preboot POWER_UP command, and a POWER_UP command to boot the part with the desired function (AM, FM).

Command

Bit 7 6 5 4 3 2 1 0

CMD ARG1 ARG2 00 XCLOAD[5:0] ARG3 CTSIEN INTSEL FASTBOOT ARG4 FUNC[3:0] 0000 ARG5 CTEN[4:0]

0x01

XSTART[7:0]

00 XIBIAS[2:0]

XMODE[2:0]

ARG Bit Name Function

Oscillator startup 01110101 = 4 MHz crystal pre-boot (first command in 4 MHz crystal

1 7:0 XSTART[7:0]

2 7:6 Reserved Always write 00.

2 5:0 XCLOAD[5:0]

3 7 CTSIEN

3 6 INTSEL

3 5 FASTBOOT

3 4:3 Reserved Always write 00.

sequence) 01110111 = boot (normal operation with external clock, or the second

command in a 4 MHz crystal sequence)

Selects the amount of additional on-chip capacitance to be connected between XTAL1 and gnd and between XTAL2 and gnd. One half of the capacitance value shown here is the additional load capacitance presented to the xtal. The minimum step size is 0.25 pF. The required value will be layout-dependent. Range is 0–0x3F (i.e. 5–20.75 pF) The EVB sets XCLOAD = 0x27.

CTS interrupt enable 0 = Disable. 1 = Enable.

CTS interrupt pin select 0=A1 pin. 1=INTB pin.

Speeds boot time when set. It is required to set this bit with Si475x-A20 and later only.

3 2:0 XBIAS[2:0]

Crystal bias current 3 = 4 MHz crystal or external clock 7 = 4 MHz crystal for boot-up

Rev. 0.9 23

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ARG Bit Name Function

Selects the boot function of the device. 0 = Boot Loader.

4 7:4 FUNC[3:0]

4 3:0 Reserved Always write 0000.

5 7:3 CNTEN[4:0]

5 2:0 XMODE[2:0]

1=FM Receive. 2=AM Receive.

Note: Values other than those listed may result in unpredictable behavior.

Enable counter 00000 = 4 MHz crystal pre-boot (first command in 4 MHz crystal

sequence) 00010 = boot (normal operation with external clock, or the second com-

mand in a 4 MHz crystal sequence)

Crystal mode 1 = Crystal 2 = External clock

24 Rev. 0.9

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Command 0x02 PART_INFO

The PART_INFO command returns the chip revision, part firmware major, minor, and build revision, and ROM ID. The command is complete when the CTS bit (and optional interrupt) is set. The command may only be sent in powerup mode.

Command

Bit76543210

CMD

Response

Bit 7 6 5 4 3 2 1 0

0x02

STATUS

RESP1

RESP2

RESP3

RESP4

RESP5

RESP6

RESP7

RESP8

RESP Bit Name Function

1 2 7:0 PART Part Number, last two digits of part number 3 7:0 PMAJOR Part Major Revision (ASCII Character Value) 4 7:0 PMINOR Part Minor Revision (ASCII Character Value)

CTS ERR XX RSQINT RDSINT ACFINT STCINT

CHIPREV[7:0]

PART[7:0]

PMAJOR[7:0]

PMINOR[7:0]

PBUILD[7:0]

Reserved

ROMID[7:0]

7:0 CHIPPREV Chip Revision

5 7:0 PBUILD Part Build Version 6 7:0 Reserved Values may vary. 7 7:0 Reserved Values may vary. 8 7:0 ROMID ROM ID

Rev. 0.9 25

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Command 0x11 POWER_DOWN

The POWER_DOWN command moves the device from powerup to powerdown mode. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup mode. Note that only the POWER_UP command is accepted in powerdown mode. If the system controller writes a command other than POWER_UP when in powerdown mode, the device will not respond. The device will only respond when a POWER_UP command is written. It is possible to power down a device and leave the oscillator running.

Command

Bit76543210

CMD ARG1 0000000 XOSC

ARG Bit Name Function

1 7:1 Reserved Always write 0000000.

10XOSC

Response

Bit76543210

STATUS

Note: The above response shows status bits for FM Receive mode (see Table 8). See Table 9 for status bits for AM Receive

mode.

CTS ERR XX RSQINT RDSINT ACFINT STCINT

0x11

0 = Full powerdown. 1 = Powerdown and leave oscillator running.

26 Rev. 0.9

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Command 0x12 FUNC_INFO

The FUNC_INFO command returns the firmware revision and patch revision for currently-loaded functional mode firmware (AM and FM). The command is complete when the CTS bit (and optional interrupt) is set. This command may only be sent in powerup mode.

Command

Bit76543210

CMD

Response

Bit 76543210

STATUS

RESP1 FWMAJOR[7:0] RESP2 FWMINOR1[7:0] RESP3 FWMINOR2[7:0] RESP4 PATCHH[7:0] RESP5 PATCHL[7:0] RESP6 FUNC[7:0]

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

RESP Bit Name Function

1 7:0 FWMAJOR[7:0] Firmware Major Revision.

2 7:0 FWMINOR1[7:0] Firmware Minor1 Revision.

3 7:0 FWMINOR2[7:0] Firmware Minor2 Revision.

4 7:0 PATCHH[7:0] Patch ID High Byte (HEX).

5 7:0 PATCHL[7:0] Patch ID Low Byte (HEX).

6 7:0 FUNC[7:0]

CTS ERR XX RSQINT RDSINT ACFINT STCINT

Returns the current functional mode: 1 = FM Receive 2=AM Receive

0x12

Rev. 0.9 27

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Command 0x13 SET_PROPERTY

The SET_PROPERTY command sets the value of a property. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.

Command

Bit76543210

CMD ARG1 00000000 ARG2 PROPH[7:0] ARG3 PROPL[7:0] ARG4 PROPDH[7:0] ARG5 PROPDL[7:0]

ARG Bit Name Function

1 7:0 Reserved Always write to 0.

27:0

37:0

47:4

57:0

PROPH

[7:0]

PROPL

[7:0]

PROPDH

[7:0]

PROPDL

[7:0]

Property Address High Byte

This byte, in combination with PROPL, is used to specify the property to modify.

Property Address Low Byte

This byte, in combination with PROPH, is used to specify the property to modify.

Property Data High Byte

This byte, in combination with PROPDL, is used to set the property value.

Property Data Low Byte

This byte, in combination with PROPDH, is used to set the property value.

0x13

Response

Bit76543210

STATUS

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

28 Rev. 0.9

CTS ERR XX RSQINT RDSINT ACFINT STCINT

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Command 0x14 GET_PROPERTY

The GET_PROPERTY command retrieves a property's value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode

Command

Bit76543210

CMD

0x14

ARG1 00000000 ARG2 PROPH[7:0] ARG3 PROPL[7:0]

ARG Bit Name Function

1 7:0 Reserved Always write 0.

Property Address High Byte.

27:0PROP

[7:0]

This byte, in combination with PROPL, is used to specify the property to get.

Property Address Low Byte.

37:0PROP

[7:0]

This byte, in combination with PROPH, is used to specify the property to get.

Response

Bit 76543210

STATUS

CTS ERR XX RSQINT RDSINT ACFINT STCINT

RESP1 XXXXXXXX RESP2 PROPD RESP3 PROPD

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

[7:0]

RESP Bit Name Function

1 7:0 Reserved Response values may vary.

27:0PROPD

[7:0] Property Data High Byte.

This byte, in combination with PROPDL, represents

the requested property value.

37:0PROPD

[7:0] Property Data Low Byte.

This byte, in combination with PROPDH, represents

the requested property value.

Rev. 0.9 29

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Command 0x15 GET_INT_STATUS

The GET_INT_STATUS command updates the bits of the status byte. This command should be called after any command that sets the STCINT, ACFINT, RDSINT, ASQINT, or RSQINT bits. When polling, this command should be periodically called to monitor the STATUS byte, and, when using interrupts, this command should be called after the interrupt is set to update the STATUS byte. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be set in powerup mode.

Command

Bit76543210

CMD

Response

Bit 76543210

STATUS

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

Command 0x17 AGC_STATUS

The AGC_STATUS command reports the current status of the AGC for FM mode. AM_AGC_STATUS (command 0x47) is used in AM/LW/SW modes. The command is complete when the CTS bit (and optional interrupt) is set. This command may only be sent when in powerup mode.

Bit76543210

CMD

RESP76543210

CTS ERR XX RSQINT RDSINT ACFINT STCINT

0x15

0x17

STATUS

RESP1 XX RESP2 FMAGC1 RESP3 FMAGC2 RESP4 PGAGAIN RESP5 FMLNAG

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

30 Rev. 0.9

CTS ERR XX RSQINT RDSINT ACFINT STCINT

MIXHI MIXLO LNAHI LNALO X X

Page 31

RESP Bit Name Function

1 7:6 Reserved Values may vary.

AN543

15MIXHI

14MIXLO

13LNAHI

12LNALO

1 1:0 Reserved Values may vary.

27:0FMAGC1

0 = FM Mixer PD high threshold is not tripped. 1 = FM Mixer PD high threshold is tripped.

0 = FM Mixer PD low threshold is not tripped. 1 = FM Mixer PD low threshold is tripped.

0 = FM LNA PD high threshold is not tripped. 1 = FM LNA PD high threshold is tripped.

0 = FM LNA PD low threshold is not tripped. 1 = FM LNA PD low threshold is tripped.

The parallel combination of these resistors indicates the current FMAGC1 attenuator resistance. The total resistance value at the pin is 800/FMAGC1. 0=10k

1=800 2=400 4=200 8=100 16 = 50  32 = 25  64 = 12.5  128 = 6.25 

—no attenuation  

The parallel combination of these resistors indicates the current FMAGC2 attenuator resistance. The total resistance value at the pin is 800/FMAGC2.

0=10k 1=800

37:0FMAGC2

4 7:0 PGAGAIN

57:0FMLNAG

2=400 4=200 8=100 16 = 50  32 = 25  64 = 12.5  128 = 6.25 

PGA gain in dB Range: 8–33

FM LNA Gain in dB Range: 2–14

—no attenuation  

Rev. 0.9 31

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Command 0x1B ANA_AUDIO_PIN_CFG

The ANA_AUDIO_PIN_CFG command configures the analog audio pins. Writing an argument byte to 0 will not change the state of the pin and is useful when using this command to query the state of the pins. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.

Note: Available in Si475x-A20 and later only.

Command

Bit76543210

CMD

ARG1 0 LROUT[6:0]

ARG Bit Name Function

1 7 Reserved Always write 0.

0 = Do not modify the behavior of this pin. 1 = Disable the output drivers, so the pins are completely inac-

1 6:0 LROUT[6:0]

Response

Bit 7 6 5 4 3 2 1 0

STATUS

RESP1 X LROUT[6:0]

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

CTS ERR XX RSQINT RDSINT ACFINT STCINT

tive and can be left floating.

2 = Configure the LOUT/ROUT pins to output audio.

3 = Configure LOUT for MPX and disable ROUT (Si4755/57 only).

0x1B

RESP Bit Name Function

1 7 Reserved Values may vary.

1 = The output drivers are disabled, so the pins are completely inactive and can be left floating.

1 6:0 LROUT[6:0]

32 Rev. 0.9

2 = LOUT/ROUT pins configured to output audio. 3 = LOUT is configured for MPX out (Si4755/57 only) and

ROUT is disabled.

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Command 0x1C INTB_PIN_CFG

The INTB_PIN_CFG command configures INTB and A1 pins. Writing an argument byte to 0 will not change the state of the pin and is useful when using this command to query the state of the pins. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.

Command

Bit76543210

CMD

ARG1 0 INTB[6:0] ARG2 0 A1[6:0]

ARG Bit Name Function

1 7 Reserved Always write to 0.

1 6:0 INTB[6:0]

2 7 Reserved Always write to 0.

26:0A1[6:0]

Response

0x1C

0 = Do not modify the behavior of this pin. 1 = Disable both the output and input drivers so the pin is

completely inactive and can be left floating. 40 = Configure this pin as the interrupt.

0 = Do not modify the behavior of this pin. 1 = Disable both the output and input drivers so the pin is

completely inactive and can be left floating. 40 = Configure this pin as the interrupt.

Bit76543210

Status

RESP1 X INTB[6:0]

RESP 2 X A1[6:0]

Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for

status bits for AM Receive mode.

RESP Bit Name Function

1 7 Reserved Values may vary.

1 6:0 INTB[6:0]

2 7 Reserved Values may vary.

26:0A1[6:0]

CTS ERR xx RSQINT RDSINT ACFINT STCINT

1 = Disabled. 40 = Configured as the interrupt.

Rev. 0.9 33

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7.1.2. Common Receiver Properties

Property 0x0000 INT_CTL_ENABLE

The INT_CTL_ENABLE property enables top-level interrupt sources. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 0x0000

INT_CTL_ENABLE

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0000 RSQREP RDSREP ACFREP STCREP CTSIEN ERRIEN 00 RSQIEN RDSIEN ACFIEN STCIEN

0000 0 0 0 0 0 0 00 0 0 0 0

Bit Name Function

15:12 Reserved Always write 0.

11 RSQREP

10 RDSREP

9 ACFREP

8 STCREP

Repeat interrupt pulse when RSQINT is set, even if a previous interrupt was generated but not acknowledged.

Repeat interrupt pulse when RDSINT is set, even if a previous interrupt was generated but not acknowledged.

Repeat interrupt pulse when ACFINT is set, even if a previous interrupt was generated but not acknowledged.

Repeat interrupt pulse when STCIEN is set, even if a previous interrupt was generated but not acknowledged.

7 CTSIEN Interrupt when CTS is set.

6 ERRIEN Interrupt when ERR is set.

5:4 Reserved Always write 0.

3 RSQIEN Interrupt when RSQIEN is set.

2 RDSIEN Interrupt when RDSINT is set.

1 ACFIEN Interrupt when ACFINT is set.

0 STCIEN Interrupt when STCIEN is set.

34 Rev. 0.9

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Property 0x0300 AUDIO_ANALOG_VOLUME

The AUDIO_ANALOG_VOLUME property sets the analog audio volume. A value of 0 will mute the audio; a value of 1 applies 62 dB of attenuation, and a value of 63 applies no attenuation. Each step accounts for 1 dB of change in the output. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 63

AUDIO_ANALOG_VOLUME

1514131211109876543210

0x000 VOL[5:0]

0x000 0x3F

Bit Name Function

15:6 Reserved Always write 0.

5:0 VOL[5:0] Sets the analog audio volume. Default is 63. Range is 0–63.

Property 0x0301 AUDIO_MUTE

The AUDIO_MUTE property mutes/unmutes each audio output (analog left or analog right).The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode.

Default: 0x0000

AUDIO_MUTE

15141312111098765432 1 0

0x0000 RIGHTMUTE LEFTMUTE

0x0000 0 0

Bit Name Function

15:2 Reserved Always write 0.

1 RIGHTMUTE

0 LEFTMUTE

0 = Right audio is not muted. 1 = Right audio is muted.

0 = Left audio is not muted. 1 = Left audio is muted.

Rev. 0.9 35

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7.2. Commands and Properties for FM Receiver

Table 11. FM Receiver Command Summary

Number Name Summary

0x30 FM_TUNE_FREQ Tunes the FM receiver to a frequency in 10 kHz steps.

0x31 FM_SEEK_START

0x32 FM_RSQ_STATUS Returns status information about the received signal quality.

0x35 FM_ACF_STATUS

0x36 FM_RDS_STATUS

Initiates a seek for a channel that meets the validation criteria for FM.

Returns status information about automatically-controlled features for the tuned station.

Returns RDS information for current channel and reads an entry from the RDS FIFO (Si4751/53/55/57 only).

0x37 FM_RDS_BLOCKCOUNT

Returns RDS expected, received, and uncorrectable block statistic information (Si4751/53/55/57 only).

36 Rev. 0.9

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Table 12. FM Receiver Properties Summary

Address Name Default Summary

A10 A20 A30 A40 A55

0x0302 AUDIO_DE_EMPHASIS

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0008 0x0008 0x0008 0x0008 0x0008

0x0400 FM_SOFT_MUTE_MAX_ATTENUATION

88888

0x0008 0x0008 0x0008 0x0008 0x0002

0x0401 FM_SOFT_MUTE_TRIGGER_THRESHOLD

88882

0x0000 0x0000 0x0000 0x0000 0x00FA

0x0402 FM_SOFT_MUTE_END_THRESHOLD

0000–6

0x01F4 0x01F4 0x01F4 0x01F4 0x01F4

0x0403 FM_SOFT_MUTE_RELEASE_TIME

500 500 500 500 500

0x0078 0x0078 0x0078 0x0078 0x0078

0x0404 FM_SOFT_MUTE_ATTACK_TIME

120 120 120 120 120

0x0405 FM_SOFT_MUTE_MAX_ATTENUATION_AGC N/A N/A

0x0406 FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC N/A N/A

0x0407 FM_SOFT_MUTE_END_THRESHOLD_AGC N/A N/A

0x0080 0x0080 0x0080

128 128 128

0x0008 0x0008 0x0008

888

0x0000 0x0000 0x0000

000

Sets the FM Receive de-emphasis.

Sets the maximum soft mute attenuation for RSSI/SNR softmute engine.

Sets the trigger threshold for RSSI/SNR softmute engine.

Sets the end threshold for RSSI/SNR softmute engine.

Sets the maximum soft mute release time ms for RSSI/SNR softmute engine.

Sets the maximum soft mute attack time in ms for RSSI/SNR softmute engine.

Sets the maximum soft mute attenuation for RSSI/SNR+AGC softmute engine.

Sets the trigger threshold for RSSI/ SNR+AGC softmute engine.

Sets the end threshold for RSSI/SNR+AGC softmute engine.

0x0408 FM_SOFT_MUTE_RELEASE_TIME_AGC N/A N/A

0x0409 FM_SOFT_MUTE_ATTACK_TIME_AGC N/A N/A

0x040A FM_SOFT_MUTE_USN_LIMITS N/A N/A

Rev. 0.9 37

0x01F4 0x01F4 0x01F4

500 500 500

0x0078 0x0078 0x0078

120 120 120

0x060E

N/A N/A

1550

Sets the maximum soft mute release time in ms for RSSI/SNR+AGC

Sets the maximum soft mute attack time in ms for RSSI/SNR+AGC softmute engine.

Set the limits for the USN input metric on the soft mute mitigation engine.

softmute engine.

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Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x040B FM_SOFT_MUTE_USN_ATTENUATION N/A N/A

0x040C FM_SOFT_MUTE_USN_ATTACK_TIME N/A N/A

0x040D FM_SOFT_MUTE_USN_RELEASE_TIME N/A N/A

0x040E FM_SOFT_MUTE_ASSI200_DEV_LIMITS N/A N/A

0x040F FM_SOFT_MUTE_ASSI200_DEV_ATTENUATION N/A N/A

0x0410 FM_SOFT_MUTE_ASSI200_DEV_ATTACK_TIME N/A N/A

0x0411 FM_SOFT_MUTE_ASSI200_DEV_RELEASE_TIME N/A N/A

0x0000

N/A N/A

0x0080

N/A N/A USN-based soft mute attack time in ms.

128

0x0100

N/A N/A USN-based soft mute release time in ms.

256

0x335A 0x335A 0x335A

13146 13146 13146

0x0000 0x0000 0x0000

000

0x0080 0x0080 0x0080

128 128 128

0x100 0x100 0x100

256 256 256

Set the limits for the attenuation when driven by USN on the soft mute mitigation engine.

Sets the trigger and end thresholds for ASSI200DEV softmute engine.

Sets the maximum soft mute attenuation for ASSI200DEV softmute engine.

Sets the maximum soft mute release time ms for ASSI200DEV softmute engine.

Sets the maximum soft mute attack time in ms for ASSI200DEV softmute engine.

0x0080 0x0080 0x0080 0x0080 0x0080

0x0700 FM_AGC_FE_CONFIG

128 128 128 128 128

0x0270 0x0270 0x0270 0x0270 0x0270

0x0701 FM_AGC_PD_CONFIG

624 624 624 624 624

0x0004 0x0004 0x0004 0x0004 0x0004

0x0702 FM_LNA_AGC_ATTACK_MS

44444

38 Rev. 0.9

Specified the input path for RF signal and other FE configuration options.

Specifies the behavior of the FM peak detectors and attenuators.

Sets the number of band RF high-peak exceeded before ate block.

milliseconds the wide-

detector must be

attenuating the appropri-

Page 39

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Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x0050 0x0050 0x0050 0x0050 0x0050

0x0703 FM_LNA_AGC_RELEASE_MS

80 80 80 80 80

Sets the number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the

0x0704 FM_LNA_AGC_PD_THRESHOLD

0x4F05 0x4F05 0x4F05 0x4F05 0x4F05

20229 20229 20229 20229 20229

0x0004 0x0004 0x0004 0x0004 0x00F8

0x0705 FM_MIXER_AGC_ATTACK_MS

4444248

0x0050 0x0050 0x0050 0x0050 0x0050

0x0706 FM_MIXER_AGC_RELEASE_MS

80 80 80 80 80

0x5103 0x5103 0x5103 0x5103 0x5103

0x0707 FM_MIXER_AGC_PD_THRESHOLD

20739 20739 20739 20739 20739

0x0000 0x0000 0x0000 0x0000 0x0000

0x0710 FM_AGC_OVERRIDE

00000

0x0000 0x0000 0x0000 0x0000

0x071B FM_AGC_RSSI_OFFSET N/A

0000

0x071C FM_MIXER_AGC_PD_THRESHOLD_MAX N/A N/A

0x071D FM_AGC_RSSI_MIXER_KEY N/A N/A

0x0055 0x0055 0x0059

85 85 89

0x140E 0x140E 0x140E

5134 5134 5134

Sets the high threshold and hysteresis for the LNA peak detector.

Sets the number of milliseconds the wideband mixer high-peak detector must be exceeded before attenuating the ate block.

Sets the number of milliseconds the wideband mixer low-peak detector must not be exceeded before increasing the gain of the appropriate block.

Sets the high threshold and hysteresis for the mixer peak detector.

Overrides the AGC setting by disabling the AGC and forcing the gain to be maximum.

Offsets the RSSI value so that it can take into account front-end gain/loss.

Sets the maximum threshold for the mixer peak detector.

Sets the RSSI threshold and hysteresis to enable keyed AGC.

appropri-

0x1006 FM_SEEK_TUNE_CHBW_HOLD_TIME N/A

0x1007 FM_TUNE_CHBW N/A N/A

Do not

Write

Rev. 0.9 39

0x0050 0x0050 0x0050

80 80 80

0x0050 0x0050 0x0050

80 80 80

Sets the length of time CHBW is held in unit of ms.

Sets the maximum CHBW allowed during the normal tune.

Page 40

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x1008 FM_TUNE_AF_CHBW N/A N/A

0x222E 0x222E 0x222E 0x222E 0x222E

0x1100 FM_SEEK_BAND_BOTTOM

8750 8750 8750 8750 8750

0x2A26 0x2A26 0x2A26 0x2A26 0x2A30

0x1101 FM_SEEK_BAND_TOP

10790 10790 10790 10790 10800

0x000A 0x000A 0x000A 0x000A 0x000A

0x1102 FM_SEEK_FREQUENCY_SPACING

10 10 10 10 10

0x1104 FM_SEEK_CHBW N/A N/A

0x0000 0x0000 0x0000 0x0000 0x0000

0x1200 FM_RSQ_INTERRUPT_SOURCE

00000

0x007F 0x007F 0x007F 0x007F 0x007F

0x1201 FM_RSQ_SNR_HIGH_THRESHOLD

127 127 127 127 127

0xFF80 0xFF80 0xFF80 0xFF80 0xFF80

0x1202 FM_RSQ_SNR_LOW_THRESHOLD

–128 –128 –128 –128 –128

0x0096 0x0096 0x0096

150 150 80

0x006E 0x006E 0x0050

110 110 80

Sets the CHBW during the AF tune/check.

Sets the lower seek boundary of the FM band in multiples of 10 kHz.

Sets the upper seek boundary for the FM band in multiples of 10 kHz.

Sets the frequency spacing for the FM band in multiples of 10 kHz when performing a seek.

Sets the CHBW during the seek.

Configures interrupt related to Received Signal Quality metrics (FM_RSQ_STATUS).

Sets high threshold which triggers the RSQ interrupt if the SNR is above this threshold.

Sets low threshold which triggers the RSQ interrupt if the SNR is below this threshold.

0x1203 FM_RSQ_RSSI_HIGH_THRESHOLD

0x007F 0x007F 0x007F 0x007F 0x007F

127 127 127 127 127

0xFF80 0xFF80 0xFF80 0xFF80 0xFF80

0x1204 FM_RSQ_RSSI_LOW_THRESHOLD

–128 –128 –128 –128 –128

0x007F 0x007F 0x007F 0x007F 0x007F

0x1205 FM_RSQ_ISSI_HIGH_THRESHOLD

127 127 127 127 127

40 Rev. 0.9

Sets high threshold which triggers the RSQ interrupt if the RSSI is above this threshold.

Sets low threshold which triggers the RSQ interrupt if the RSSI is below this threshold.

Sets high threshold, which triggers the interrupt if image signal strength is above this threshold.

RSQ

Page 41

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0xFF80 0xFF80 0xFF80 0xFF80 0xFF80

0x1206 FM_RSQ_ISSI_LOW_THRESHOLD

–128 –128 –128 –128 –128

0x007F 0x007F 0x007F 0x007F 0x007F

0x1207 FM_RSQ_MULTIPATH_HIGH_THRESHOLD

127 127 127 127 127

Sets low threshold which triggers the RSQ interrupt if image signal strength is below this threshold.

Sets high threshold which triggers the RSQ interrupt if Multipath is above this threshold.

0x1208 FM_RSQ_MULTIPATH_LOW_THRESHOLD

0x1300 FM_ACF_INTERRUPT_SOURCE

0x1301 FM_ACF_SM_THRESHOLD

0x1302 FM_ACF_CHBW_THRESHOLD

0x1303 FM_ACF_HICUT_THRESHOLD

0x1304 FM_ACF_HIBLEND_THRESHOLD

0x1305 FM_ACF_BLEND_THRESHOLD

0x1306 FM_ACF_CONTROL_SOURCE

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x001F 0x001F 0x001F 0x001F 0x001F

31 31 31 31 31

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0001 0x0001 0x0001 0x0001 0x0003

11113

Sets low threshold which triggers the RSQ interrupt if Multipath is below this threshold.

Enables the ACF interrupt sources.

Sets the softmute interrupt threshold in dB.

Sets the Channel Filter Bandwidth interrupt threshold in units of kHz.

Sets the HICUT interrupt threshold in units of 100 Hz.

Sets the HIBLEND interrupt threshold in units of 100 Hz.

Sets the Stereo Blend interrupt threshold in units of percent L–R gain.

Sets the controlling metric for ACF features.

0x1307 FM_ACF_HOLD_TIME N/A N/A N/A N/A

0x004B 0x004B 0x004B 0x004B 0x004B

0x2000 FM_VALID_MAX_TUNE_ERROR

75 75 75 75 75

Rev. 0.9 41

0x0064

100

Sets the ACF hold time after tune.

Sets the maximum frequency error in 2 ppm allowed before setting the AFCRL indicator.

Page 42

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x0006 0x0006 0x0006 0x0006 0x0006

0x2001 FM_VALID_RSSI_TIME

0x2002 FM_VALID_SNR_TIME

0x2003 FM_VALID_SNR_THRESHOLD

0x2004 FM_VALID_RSSI_THRESHOLD

0x2005 FM_VALID_ISSI_THRESHOLD

0x2006 FM_VALID_MULT_THRESHOLD N/Z

0x2007 FM_VALID_AF_TIME N/A

0x2008 FM_VALID_AF_RDS_TIME N/A N/A

66666

0x0012 0x0012 0x0012 0x0012 0x0012

18 18 18 18 18

0x0008 0x0008 0x0008 0x0008 0x0008

88888

0x000C 0x000C 0x000C 0x000C 0x000C

12 12 12 12 12

Do not

write

Do not

write

0x0064 0x0064 0x0064 0x0064

100 100 100 100

0x0005 0x0005 0x0002 0x0002

5522

0x001E 0x001E 0x001E

30 30 30

0x0078 0x0078 0x0078

120 120 120

Sets the amount of time in milliseconds to allow the RSSI metric to settle before evaluating.

Sets the amount of time in milliseconds to allow the SNR metric to settle before evaluating.

Sets the SNR threshold for a valid FM Seek Tune.

Sets the RSSI threshold for a valid FM Seek Tune.

Sets the ISSI threshold for injection side switch during FM Seek Tune.

Sets the multipath threshold for a valid FM Seek/Tune.

Sets the amount of time in milliseconds to allow the RSSI and SNR metrics to settle before evaluating during an AF check/tune.

Sets the amount of time in milliseconds to allow the PI code to be captured before evaluating.

0x2009 FM_VALID_AF_PI N/A N/A

0x200A FM_VALID_ASSI_THRESHOLD N/A N/A

0x200B FM_VALID_AF_PI_MASK N/A N/A

42 Rev. 0.9

0x0000 0x0000 0x0000

000

0x503C 0x503C 0x503C

20540 20540 20540

0xFFFF 0xFFFF 0xFFFF

65535 65535 65535

Sets the PI code to match during AF tune.

Sets the ASSI/ASSI200 threshold for valid FM Seek/Tune.

Sets the mask on PI code match during AF tune.

Page 43

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x200C FM_VALID_FREQOFF_SCALE N/A N/A N/A

0x0000 0x0000

0x0064 0x0064

0x200D FM_VALID_FREQOFF_FILTER N/A N/A N/A

100 100

0x0012 0x0012 0x0012 0x0012 0x0012

0x2100 FM_NB_DETECT_THRESHOLD

18 18 18 18 18

0x0005 0x0005 0x0005 0x0005 0x0005

0x2101 FM_NB_INTERVAL

55555

0x2103 FM_NB_SECONDARY_DETECT_THRESHOLD N/A N/A N/A N/A

0x3500 0x3500 0x1D71

0x2105 FM_NB_WEAK_DETECT_THRESHOLD N/A N/A

13568 13568 7537

0x0032 0x0032 0x0032 0x0032 0x0023

0x2106 FM_NB_STRONG_SIGNAL_SHUTOFF

50 50 50 50 35

0x0000 0x0000 0x0000

0x2109 FM_NB_MODE_CONTROL N/A N/A

000

0x0000

Changes FREQOFF from bppm units to some multiple of Hz.

Changes the amount that FREQOFF is filtered.

Sets the threshold for detecting impulses in dB above the noise floor.

Sets the interval that original samples are replaced by interpolated clean samples.

Sets the threshold for detecting impulses in percentage of average to peak

Sets the threshold for detecting impulses with the weak signal noise blanker.

The RSSI based shutoff threshold. Used to turn off the noise blanker under strong signal conditions.

Sets options of the noise blankers.

0x0005 0x0005 0x0005

0x210A FM_NB_WEAK_BLANK_INTERVAL N/A N/A

555

0x0B09 0x0B09 0x0B09

0x210B FM_NB_STRONG_WEAK_SWITCH N/A N/A

2825 2825 2825

0x2111 FM_NB_CIMP_HICUT_LIMIT N/A N/A N/A N/A

Rev. 0.9 43

0x0A14

2580

Number of samples that are replaced by interpolated clean samples.

Sets the SNR/RSSI thresholds for determining whether strong or weak blanker is used.

Sets the HiCut multipath threshold when continuous impulses are detected.

Page 44

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x2112 FM_NB_CIMP_HICUT_FREQ N/A N/A N/A N/A

0x2113 FM_NB_CIMP_HICUT_ATTACK N/A N/A N/A N/A

0x2114 FM_NB_CIMP_HICUT_RELEASE N/A N/A N/A N/A

0x2115 FM_NB_CIMP_DETCNTR N/A N/A N/A N/A

0x2116 FM_NB_CIMP_A2PTH N/A N/A N/A N/A

0x2117 FM_NB_CIMP_IMPDET N/A N/A N/A N/A

0x2118 FM_NB_CIMP_MPX_INTV N/A N/A N/A N/A

0x9637 0x9637 0x9637 0x9637 0x9637

0x2200 FM_CHBW_SQ_MIN_MAX

38455 38455 38455 38455 38455

0x000C 0x000C 0x000C 0x000C 0x000C

0x2201 FM_CHBW_SQ_HIGH_THRESHOLD

12 12 12 12 12

0x6401

25601

0x0001

0x0008

0x0402

1026

0x0800

2048

0x400A

16394

0x0A0A

2570

Sets the HiCut cut-off frequency when continuous impulses are detected.

Sets the HiCut attack time when continuous impulses are detected.

Sets the HiCut release time when continuous impulses are detected

Continuous impulse detection counter setting.

Independent IQ impulse detection threshold for continuous impulse detection.

Aggressive noise blanker impulse detection threshold when continuous impulses detected

Aggressive MPX blanker interval when continuous impulses detected replacing property 0x2101

Sets the maximum and minimum channel filter bandwidth in units of kHz based on RSSI/STRONGDEV (or SNR) in weak signal condition.

Sets the RSSI/STRONGDEV (or SNR) threshold for maximum channel filter bandwidth in weak signal condition.

0xFFFC 0xFFFC 0xFFFC 0xFFFC 0x0002

0x2202 FM_CHBW_SQ_LOW_THRESHOLD

–4 –4 –4 –4 2

0x0010 0x0010 0x0010 0x0010 0x0010

0x2203 FM_CHBW_SQ_WIDENING_TIME

16 16 16 16 16

44 Rev. 0.9

Sets the RSSI/STRONGDEV (or SNR) threshold for minimum channel filter bandwidth in weak signal condition.

Sets the channel filter bandwidth widening time based on RSSI/STRONGDEV (or SNR) in weak signal condition.

Page 45

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x2204 FM_CHBW_SQ_NARROWING_TIME

0x2205 FM_CHBW_ASSI_MIN_MAX

0x2206 FM_CHBW_ASSI_LOW_THRESHOLD

0x2207 FM_CHBW_ASSI_HIGH_THRESHOLD

0x2208 FM_CHBW_ASSI_WIDENING_TIME

0x2209 FM_CHBW_ASSI_NARROWING_TIME

0x220A FM_CHBW_ASSI200_MIN_MAX

0x220B FM_CHBW_ASSI200_LOW_THRESHOLD

0x0800 0x0800 0x0800 0x0800 0x0800

2048 2048 2048 2048 2048

0x9623 0x9623 0x9623 0x9623 0x9623

38435 38435 38435 38435 38435

0x0007 0x0007 0x0007 0x0007 0x0007

77777

0x0014 0x0014 0x0014 0x0014 0x0014

20 20 20 20 20

0x0001 0x0001 0x0C80 0x0C80 0x0C80

1 1 3200 3200 3200

0x0140 0x0140 0x0140 0x0140 0x0140

320 320 320 320 320

0x9632 0x9650 0x9650 0x9650 0x964B

38450 38480 38480 38480 38475

0xFFF6 0xFFF6 0xFFF6 0xFFF6 0x0000

–10 –10 –10 –10 0

Sets the channel filter bandwidth narrowing time based on RSSI/STRONGDEV (or SNR) in weak signal condition.

Sets the delta (HASSI,LASSI) threshold for maximum and minimum channel filter bandwidth in units of kHz.

Sets the delta (HASSI,LASSI) threshold for maximum channel filter bandwidth

Sets the delta (HASSI,LASSI) threshold for minimum channel filter bandwidth.

Sets the channel filter bandwidth widening time based on the delta (HASSI,LASSI).

Sets the channel filter bandwidth narrowing time based on the delta (HASSI,LASSI).

Sets the ASSI200 maximum and minimum channel filter bandwidth in units of kHz.

Sets the ASSI200 threshold for maximum channel filter bandwidth.

0x220C FM_CHBW_ASSI200_HIGH_THRESHOLD

0x000A 0x000A 0x000A 0x000A 0x000A

10 10 10 10 10

0x0001 0x0001 0xC80 0xC80 0xFA0

0x220D FM_CHBW_ASSI200_WIDENING_TIME

1 1 3200 3200 4000

0x0140 0x0140 0x0140 0x0140 0x0140

0x220E FM_CHBW_ASSI200_NARROWING_TIME

320 320 320 320 320

0x220F FM_CHBW_WEAKSIG_THR N/A

Sets the ASSI200 threshold for minimum channel filter bandwidth.

Sets the channel filter bandwidth widening time based on ASSI200.

Sets the channel filter bandwidth narrowing time based on ASSI200.

0x100D 0x100D 0x100D 0x100D

4109 4109 4109 4109

Rev. 0.9 45

Sets the hysteresis window for the weak signal channel filter bandwidth engine.

Page 46

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x2210 FM_CHBW_BLOCKER_THR N/A

0x2214 FM_CHBW_ASSI_B_CONTROL N/A N/A

0x2215 FM_CHBW_STRONGDEV_MIN_MAX N/A

0x2216 FM_CHBW_STRONGDEV_LOW_THRESHOLD N/A

0x2217 FM_CHBW_STRONGDEV_HIGH_THRESHOLD N/A

0x2218 FM_CHBW_STRONGDEV_WIDENING_TIME N/A

0x2219 FM_CHBW_STRONGDEV_NARROWING_TIME N/A

0x221A FM_CHBW_ASSI200DEV_MIN_MAX N/A N/A

Do not

Write

0x9680 0x9680 0x9680 0x9664

38528 38528 38528 38500

0x0008 0x0008 0x0008 0x0008

8888

0x0013 0x0013 0x0013 0x0013

19 19 19 19

0x1000 0x1000 0x1000 0x1000

4096 4096 4096 4096

0x0200 0x0200 0x0200 0x0200

512 512 512 512

0x140A 0x140A 0x140A

5130 5130 5130

0x0000 0x0200 0x0200

0 512 512

0x5020 0x9646 0x9646

20512 38470 38470

Sets the threshold and hysteresis to enable channel filter bandwidth based on ASSI200DEV.

Selects the behavior of ASSI-B channel filter bandwidth control engine.

Sets the maximum and minimum channel filter bandwidth in units of kHz based on STRONGDEV.

Sets the STRONGDEV threshold for maximum channel filter bandwidth.

Sets the STRONGDEV threshold for minimum channel filter bandwidth.

Sets the channel filter bandwidth widening time based on STRONGDEV.

Sets the channel filter bandwidth narrowing time based on STRONGDEV.

Sets the maximum and minimum channel filter bandwidth in units of kHz based on ASSI200DEV.

0x221B FM_CHBW_ASSI200DEV_LOW_THRESHOLD N/A N/A

0x221C FM_CHBW_ASSI200DEV_HIGH_THRESHOLD N/A N/A

0x221D FM_CHBW_ASSI200DEV_WIDENING_TIME N/A N/A

46 Rev. 0.9

0x0032 0x0032 0x0032

50 50 50

0x005A 0x005A 0x005A

90 90 90

0x0800 0x0800 0x0800

2048 2048 2048

Sets the ASSI200DEV threshold for maximum channel filter bandwidth.

Sets the ASSI200DEV threshold for minimum channel filter bandwidth.

Sets the channel filter bandwidth widening time based on ASSI200DEV.

Page 47

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x221E FM_CHBW_ASSI200DEV_NARROWING_TIME N/A N/A

0x221F FM_CHBW_ASSI_B_MIN_MAX N/A N/A

0x2220 FM_CHBW_ASSI_B_LOW_THRESHOLD N/A N/A

0x2221 FM_CHBW_ASSI_B_HIGH_THRESHOLD N/A N/A

0x2222 FM_CHBW_ASSI_B_WIDENING_TIME N/A N/A

0x2223 FM_CHBW_ASSI_B_NARROWING_TIME N/A N/A

0x3105 FM_LOWCUT_MIN_FREQ

0x3106 FM_LOWCUT_MAX_FREQ

Do Not

Write

N/A

0x0080 0x0080 0x0080

128 128 128

0x9696 0x9696 0x9696

38550 38550 38550

0x0000 0x0000 0xFFFB

00-5

0x0000 0x0000 0x0005

005

0x0001 0x0001 0x0FA0

1 1 4000

0x0001 0x0001 0x0190

1 1 400

0x0000 0x0000 0x0000

000

0x0000 0x0000 0x0000

000

Sets the channel filter bandwidth narrowing time based on ASSI200DEV.

Sets the maximum and minimum channel filter bandwidth in units of kHz based on max (HASSI,LASSI).

Sets the max (HASSI,LASSI) threshold for maximum channel filter bandwidth.

Sets the max (HASSI,LASSI) threshold for minimum channel filter bandwidth.

Sets the channel filter bandwidth widening time based on max (HASSI,LASSI).

Sets the channel filter bandwidth narrowing time based on max (HASSI,LASSI).

Sets the minimum LowCut cutoff frequency.

Sets the maximum LowCut cutoff frequency.

0x3200 FM_POP_NOISE_FADE_HYST

0x3207 FM_POP_NOISE_MODE

0x3208 FM_POP_NOISE_RSSI_THRESHOLDS N/A

Do not

Write

0x0001 0x0001 0x0001 0x0001 0x0002

11112

Do not

Write

0xECE7 0xECE7 0xECE7 0xFDF9

60647 60647 60647 65017

Rev. 0.9 47

0x0A06 0x0A06 0x0604

2566 2566 1540

Sets the thresholds for FM pop filter fading hysteresis

Sets the pop mitigation mode.

Sets the change in RSSI thresholds for maximum and minimum MPX limiting (set by property 0x3209).

Page 48

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x3209 FM_POP_NOISE_RSSI_MPX_LIMIT N/A

0x320A FM_POP_NOISE_RSSI_MPX_ATTACK N/A

0x320B FM_POP_NOISE_RSSI_MPX_RELEASE N/A

0x320C FM_POP_NOISE_MPX_USN_THRESHOLDS N/A

0x320D FM_POP_NOISE_MPX_USN_LIMITS N/A

0x320E FM_POP_NOISE_MPX_USN_ATTACK N/A

0x320F FM_POP_NOISE_MPX_USN_RELEASE N/A

0x007F 0x007F 0x007F 0x007F 0x007F

0x3210 FM_POP_NOISE_SCALE

127 127 127 127 127

0x1009 0x1009 0x1009 0x0502

4105 4105 4105 1282

0x0001 0x0001 0x0001 0x001E

11130

0x0001 0x0001 0x0001 0x0BB8

1 1 1 3000

0x03FE 0x03FE 0x03FE 0x0501

1022 1022 1022 1281

0x1009 0x1009 0x1009 0x0502

4105 4105 4105 1282

0x0001 0x0001 0x0001 0x001E

11130

0x0001 0x0001 0x0001 0x0BB8

1 1 1 3000

Sets the minimum and maximum limit for MPX limiter based on change in RSSI.

Sets the attack rate for MPX limiter pop mitigation.

Sets the release rate for pop mitigation.

Sets the ratio of MPX to USN thresholds for maximum and minimum MPX limiting (set by property 0x320D).

Sets the maximum and minimum limit for MPX limiter based on ratio of MPX to USN.

Sets the attack rate for MPX limiter pop mitigation.

Sets the release rate for pop mitigation.

Sets the scale for the FM pop filter.

0x3400 FM_MULT_EQ_CTL N/A N/A

0x3401 FM_MULT_EQ_NOISE_DISABLE N/A N/A

0x3402 FM_MULT_EQ_CTL_STEP N/A N/A

0x3409

48 Rev. 0.9

FM_EQ_CTL_AUTOTAP N/A N/A N/A N/A

0x0601 0x0601 0x8001

1537 1537 32769

0xFC81 0xFCFA 0xFCFA Sets the RSSI threshold below which the

64641 64762 64762

0x0000 0x0000 0x0000

000

0x03FB

1019

Controls the multipath channel equalizer.

channel equalizer will use noise measurement to enable/disable channel equalizer.

Sets the channel rate.

Sets the threshold for channel equalizer auto tap control.

equalizer tap updating

Page 49

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x3500 FM_BLEND_RSSI_THRESHOLDS

0x3501 FM_BLEND_RSSI_STEREO_SEP

0x3502 FM_BLEND_RSSI_ATTACK_TIME

0x3503 FM_BLEND_RSSI_RELEASE_TIME

0x3508 FM_BLEND_MULTIPATH_THRESHOLDS

0x3509 FM_BLEND_MULTIPATH_STEREO_SEP

0x350A F M _BLEND_MU LT I PAT H _ATTACK_TIME

0x350B FM_BLEND_MULTIPATH_RELEASE_TIME

0x3719 0x3719 0x3719 0x3719 0x3719

14105 14105 14105 14105 14105

0x2D00 0x2D00 0x2D00 0x2D00 0x2D00

11520 11520 11520 11520 11520

0x0010 0x0010 0x0010 0x0010 0x0010

16 16 16 16 16

0x0FA0 0x0FA0 0xFA0 0xFA0 0xFA0

4000 4000 4000 4000 4000

0x1E3C 0x1E3C 0x1E3C 0x1E3C 0x0A14

7740 7740 7740 7740 2580

0x2D00 0x2D00 0x2D00 0x2D00 0x2D00

11520 11520 11520 11520 11520

0x0010 0x0010 0x0010 0x0010 0x0010

16 16 16 16 16

0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0

4000 4000 4000 4000 4000

Sets the thresholds for the RSSI metric for the stereo blend mitigation engine.

Set the limits for the stereo separation when driven by RSSI on the stereo blend mitigation engine.

Sets the stereo blend attack time in ms.

Sets the stereo blend release time in ms.

Sets the thresholds for the multipath metric for the stereo blend mitigation engine.

Sets the limits for the stereo separation when driven by multipath on the stereo blend mitigation engine.

Sets the stereo blend attack time in ms.

Sets the stereo blend release time in ms.

0x3510 FM_BLEND_USN_THRESHOLDS

0x3511 FM_BLEND_USN_STEREO_SEP

0x3512 FM_BLEND_USN_ATTACK_TIME

0x341B 0x341B 0x341B 0x341B 0x341B

13339 13339 13339 13339 13339

0x2D00 0x2D00 0x2D00 0x2D00 0x2D00

11520 11520 11520 11520 11520

0x0010 0x0010 0x0010 0x0010 0x0010

16 16 16 16 16

Rev. 0.9 49

Set the thresholds for the USN metric for the stereo blend mitigation engine.

Sets the limits for the stereo separation when driven by USN on the stereo blend mitigation engine.

Sets the stereo blend attack time in ms.

Page 50

AN543

Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x3513 FM_BLEND_USN_RELEASE_TIME

0x3518 FM_BLEND_CHBW_LIMITS

0x3519 FM_BLEND_CHBW_STEREO_SEP

0x351A FM_BLEND_CHBW_ATTACK_TIME

0x351B FM_BLEND_CHBW

0x3600 FM_HICUT_RSSI_THRESHOLDS

0x3601 FM_HICUT_RSSI_CUTOFF_FREQ

0x3602 FM_HICUT_RSSI_ATTACK_TIME

0x3603 FM_HICUT_RSSI_RELEASE_TIME

0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0

4000 4000 4000 4000 4000

0x0000 0X0000 0x0000 0x0000 0x0000

00000

0x2D2D 0x2D2D 0x2D2D 0x2D2D 0x2D2D Set the limits for the stereo separation

11565 11565 11565 11565 11565

0x0001 0x0001 0x0001 0x0001 0x0001

11111

0x0001 0x0001 0x0001 0x0001 0x0001

11111

0x230F 0x230F 0x230F 0x230F 0x230F

8975 8975 8975 8975 8975

0xB428 0xB428 0xB428 0xB428 0xB419

46120 46120 46120 46120 46105

0x0010 0x0010 0x0010 0x0010 0x0064

16 16 16 16 100

0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0

4000 4000 4000 4000 4000

Sets the stereo blend release time in ms.

Set the limits for CHBW input metric on the stereo blend mitigation engine

when driven by CHBW on the stereo blend mitigation engine

Set stereo blend attack time in ms

Set stereo blend release time in ms

Sets the thresholds for the RSSI metric for the L+R high cut mitigation engine.

Sets the limits for the cutoff frequency when driven by RSSI on the L+R high cut mitigation engine.

Sets the L+R high cut attack time in ms.

Sets the L+R high cut release time in ms.

0x3608 FM_HICUT_MULTIPATH_THRESHOLDS

0x3250 0x3250 0x3250 0x3250 0x0A14

12880 12880 12880 12880 2580

0xB428 0xB428 0xB428 0xB428 0x6419

0x3609 FM_HICUT_MULTIPATH_CUTOFF_FREQ

46120 46120 46120 46120 25625

0x0010 0x0010 0x0010 0x0010 0x0064

0x360A FM_HICUT_MULTIPATH_ATTACK_TIME

16 16 16 16 100

50 Rev. 0.9

Sets the thresholds for the multipath metric for the L+R high cut mitigation engine.

Set the limits for the cutoff frequency when driven by multipath on the L+R high cut mitigation engine.

Sets the L+R high cut attack time in ms.

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Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x360B FM_HICUT_MULTIPATH_RELEASE_TIME

0x3610 FM_HICUT_USN_THRESHOLDS

0x3611 FM_HICUT_USN_CUTOFF_FREQ

0x3612 FM_HICUT_USN_ATTACK_TIME

0x3613 FM_HICUT_USN_RELEASE_TIME

0x3618 FM_HICUTN_CHBW_LIMITS

0x3619 FM_HICUTN_CHBW_CUTOFF_FREQ

0x361A FM_HICUTN_CHBW_ATTACK_TIME

0x361B HM_HICUTN_CHBW_RELEASE_TIME

0x3700 FM_HIBLEND_RSSI_THRESHOLDS

0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0

4000 4000 4000 4000 4000

0x250F 0x250F 0x250F 0x250F 0x250F

9487 9487 9487 9487 9487

0xB428 0xB428 0xB428 0xB428 0xB419

46120 46120 46120 46120 46105

0x0010 0x0010 0x0010 0x0010 0x0064

16 16 16 16 100

0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0

4000 4000 4000 4000 4000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0xB4B4 0xB4B4 0xB4B4 0xB4B4 0xB4B4 Set the limits for the cutoff frequency when

46260 46260 46260 46260 46260

0x0001 0x0001 0x0001 0x0001 0x0001

11111

0x0001 0x0001 0x0001 0x0001 0x0001

11111

0x371B 0x371B 0x371B 0x371B 0x371B

14107 14107 14107 14107 14107

Sets the L+R high cut release time in ms.

Sets the thresholds for the USN metric for the L+R high cut mitigation engine.

Sets the limits for the cutoff frequency when driven by USN on the L+R high cut mitigation engine.

Sets the L+R high cut attack time in ms.

Sets the L+R high cut release time in ms.

Set the limits for the CHBW input metric on L+R high cut mitigation engine

driven by CHBW on the L+R high cut mitigation engine

Set L+R high cut attack time in ms

Set L+R high cut release time in ms

Sets the thresholds for the RSSI metric for the L–R high cut mitigation engine.

0x3701 FM_HIBLEND_RSSI_CUTOFF_FREQ

0x3702 FM_HIBLEND_RSSI_ATTACK_TIME

0xB41E 0xB41E 0xB41E 0xB41E 0xB419

46110 46110 46110 46110 46105

0x0004 0x0004 0x0004 0x0004 0x0064

4444100

Rev. 0.9 51

Sets the limits for the cutoff frequency when driven by RSSI on the L–R high-blend mitigation engine.

Sets the L–R high-blend attack time in ms.

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Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x3703 FM_HIBLEND_RSSI_RELEASE_TIME

0x3708 FM_HIBLEND_MULTIPATH_THRESHOLDS

0x3709 FM_HIBLEND_MULTIPATH_CUTOFF_FREQ

0x370A FM_HIBLEND_MULTIPATH_ATTACK_TIME

0x370B FM_HIBLEND_MULTIPATH_RELEASE_TIME

0x3710 FM_HIBLEND_USN_THRESHOLDS

0x3711 FM_HIBLEND_USN_CUTOFF_FREQ

0x3712 FM_HIBLEND_USN_ATTACK_TIME

0x1F40 0x1F40 0x1F40 0x1F40 0x0FA0

8000 8000 8000 8000 4000

0x193C 0x193C 0x193C 0x193C 0x080F

6460 6460 6460 6460 2063

0xB41E 0xB41E 0xB41E 0xB41E 0x6419

46110 46110 46110 46110 25625

0x0004 0x0004 0x0004 0x0004 0x0064

4444100

0x1F40 0x1F40 0x1F40 0x1F40 0x0FA0

8000 8000 8000 8000 4000

0x371E 0x371E 0x371E 0x371E 0x371E

14110 14110 14110 14110 14110

0xB41E 0xB41E 0xB41E 0xB41E 0x9619

46110 46110 46110 46110 38425

0x0004 0x0004 0x0004 0x0004 0x0064

4444100

Sets the L–R high-blend release time in ms.

Sets the thresholds for the multipath metric for the L–R high-blend mitigation engine.

Sets the limits for the cutoff frequency when driven by multipath on the L–R high-blend mitigation engine.

Sets the L–R high-blend attack time in ms.

Sets the L–R high-blend release time in ms.

Sets the thresholds for the USN metric for the L–R high-blend mitigation engine.

Sets the limits for the cutoff frequency when driven by USN on the L–R high-blend mitigation engine.

Sets the L–R high-blend attack time in ms.

0x3713 FM_HIBLEND_USN_RELEASE_TIME

0x3718 FM_HIBLEND_CHBW_LIMITS

0x3719 FM_HIBLEND_CHBW_CUTOFF_FREQ

52 Rev. 0.9

0x1F40 0x1F40 0x1F40 0x1F40 0x0FA0

8000 8000 8000 8000 4000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0xB4B4 0xB4B4 0xB4B4 0xB4B4 0xB4B4 Set the limits for the cutoff frequency when

46260 46260 46260 46260 46260

Sets the L–R high-blend release time in ms.

Set the limits for the CHBW input metric on the hi-blend (L-R high cut) mitigation engine.

driven by CHBW on the hi-blend (L-R high cut) mitigation engine.

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Table 12. FM Receiver Properties Summary (Continued)

Address Name Default Summary

A10 A20 A30 A40 A55

0x371A FM_HIBLEND_CHBW_ATTACK_TIME

0x371B FM_HIBLEND_CHBW_RELEASE_TIME

0x4000 FM_RDS_INTERRUPT_SOURCE

0x0001 0x0001 0x0001 0x0001 0x0001

11111

0x0001 0x0001 0x0001 0x0001 0x0001

11111

0x0000 0x0000 0x0000 0x0000 0x0000

00000

Set hi-blend (L-R high cut) attack time in ms

Set hi-blend (L-R high cut) release time in ms.

Configures interrupt related to RDS.

0x4001 FM_RDS_INTERRUPT_FIFO_COUNT

0x4002 FM_RDS_CONFIG

0x4003 FM_RDS_CONFIDENCE

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x0000 0x0000 0x0000 0x0000 0x0000

00000

0x1111 0 x 1111 0x1111 0x1111 0x 1111

4369 4369 4369 4369 4369

Sets the minimum number of RDS groups stored in the RDS FIFO before RDSRECV is set.

Configures RDS settings to enable RDS processing (RDSEN) and set RDS block error thresholds.

Sets the confidence level requirement for each RDS block.

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7.2.1. FM Receiver Commands

Command 0x30 FM_TUNE_FREQ

The FM_TUNE_FREQ command sets the FM Receiver to tune to a frequency between 64 and 108 MHz in 10 kHz units. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent in powerup mode. The command clears the STC bit if it is already set.

Command

Bit 7 6 5 4 3 2 1 0

CMD ARG1 ARG2 FREQH[7:0] ARG3 FREQL[7:0]

ARG Bit Name Function

17:6Reserved

1 5:4 TUNEMODE[1:0]

13Reserved

00 TUNEMODE[1:0] 0

Sets the Desired Tuning Mode.

0 = Validated normal tune: Unconditionally stay on the new channel after tune, tune status is valid. 1 = Invalidated fast tune: Unconditionally stay on the new channel after tune, tune status invalid. 2 = Validated AF Tune: Jump back to previous channel if metric thresholds are not met (Si4755/57 only). 3 = Validated AF Check: Unconditionally jump back to the previous channel (Si4755/57 only).

Smoothly transition audio state after tune. 0 = Initialize audio state to match this new channel.

SMOOTH-

METRICS

1 = Transition audio state from previous channel values to the new channel values.

Note: This is the recommended setting when performing an AF

0x30

SMOOTHMETRICS INJSIDE[1:0]

Always write 0.

check.

Selects Injection Side.

1 1:0 INJSIDE[1:0]

54 Rev. 0.9

0 = Automatic injection side selection by the tuner. 1 = Force low-side injection. 2 = Force high-side injection.

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ARG Bit Name Function

Tune Frequency High Byte.

27:0FREQ

37:0FREQ

Response

Bit76543210

[7:0]

This byte in combination with FREQL selects the tune frequency in units of 10 kHz. In FM mode the valid range is from 6400 to 10800 (64–108 MHz).

Tune Frequency Low Byte.

This byte in combination with FREQH selects the tune frequency in units of 10 kHz. In FM mode, the valid range is from 6400 to 10800 (64–108 MHz).

STATUS

CTS ERR XX RSQINT RDSINT ACFINT STCINT

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Command 0x31 FM_SEEK_START

The FM_SEEK_START command begins searching for a valid station. In order for a station to be considered valid,

each of the following thresholds must be met:

FM_VALID_ASSI_THRESHOLD, FM_VALID_ISSI_THRESHOLD, and FM_VALID_MAX_TUNE_ERROR. Clears any pending STCINT, RSQINT, or RDSINT interrupt status. Seek can be cancelled through setting the CANCEL bit in the FM_RSQ_STATUS command. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent in powerup mode. The command clears the STCINT bit if it is already set.

Command

Bit76543210

FM_VALID_SNR_THRESHOLD, FM_VALID_RSSI_THRESHOLD,

CMD ARG1 0000 SEEKUP WRAP 00

ARG Bit Name Function

1 7:4 Reserved Always write 0000.

Seek Up/Down.

1 3 SEEKUP

12WRAP

1 1:0 Reserved Always write 00.

Response

Bit76543210

STATUS

CTS ERR XX RSQINT RDSINT ACFINT STCINT

Determines the direction of the search, either UP = 1, or DOWN = 0.

Wrap/Halt.

Determines whether the seek should Wrap = 1, or Halt = 0 when it hits the band limit.

0x31

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Command 0x32 FM_RSQ_STATUS

The FM_RSQ_STATUS command returns status information about the received signal quality. This command returns the Received Signal Strength Indicator (RSSI), Signal to Noise Ratio (SNR), Adjacent Channel Strength for 200 kHz (ASSI200), Adjacent Channel Strength for 100 kHz (LASSI and HASSI), frequency offset (FREQOFF), Multipath (MULT), Ultrasonic Noise (USN), Pilot Deviation (PILOTDEV), RDS Deviation (RDSDEV), Adjacent Channel Deviation for 200 kHz (ASSI200DEV), Deviation (DEV and STRONGDEV), and RDS PI code (RDSPI) associated with the desired channel. It also indicates valid channel (VALID) and AFC rail status (AFCRL). This command can be used to check if the received signal is above the RSSI high threshold as reported by RSSIHINT or below the RSSI low threshold as reported by RSSILINT. It can also be used to check if the signal is above the SNR high threshold as reported by SNRHINT or below the SNR low threshold as reported by SNRLINT. It can be used to check if the detected multipath is above the Multipath high threshold as reported by MULTHINT or below the Multipath low threshold as reported by MULTLINT.

The command clears the RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT, MULTHINT, and MULTLINT interrupt bits when the RSQACK bit of ARG1 is set. If the condition is still true after the interrupt is cleared, another interrupt will fire assuming that bit is enabled in FM_RSQ_INTERRUPT_SOURCE. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup mode.

FM_RSQ_

STATUS

Command

CMD ARG1

ARG Bit Name Function

1 7:4 Reserved Always write 0000.

1 3 RSQACK

1 2 ATTUNE

1 1 CANCEL

76543210

0x32

0000 RSQACK ATTUNE CANCEL STCACK

Clears RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT, MULTHINT, and MULTLINT if set.

Returns the values of metrics as of tune time. When the ATTUNE bit is set, values returned for RSQ_STATUS are the values calculated at tune and do not change unless another FM_TUNE_FREQ or FM_SEEK_START command is called. This feature can be used to determine why seek stopped at the current station.

Aborts a seek or tune currently in progress. 0 = Don't abort. 1 = Abort.

1 0 STCACK Clears the STC interrupt status indicator if set.

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Response

Bit 7 6 5 4 3 2 1 0

STATUS

RESP1 MULTHINT MULTLINT ISSIHINT ISSILINT SNRHINT SNRLINT RSSIHINT RSSILINT RESP 2 BLTF X SNRREADY RSSIREADY X INJSIDE AFCRL VALID RESP 3 READFREQ[15:8] RESP 4 READFREQ[7:0] RESP 5 FREQOFF[7:0] RESP 6 RSSI[7:0] RESP 7 SNR[7:0] RESP 8 ISSI[7:0] RESP 9 LASSI[7:0]

RESP 10 HASSI[7:0] RESP 11 MULT[7:0] RESP 12 DEV[7:0] RESP 13 XXXXXXXX

CTS ERR XX RSQINT RDSINT ACFINT STCINT

RESP 14 XXXXXXXX RESP 15 ASSI200[7:0] RESP 16 USN[7:0] RESP 17 PILOTDEV[7:0] RESP 18 RDSDEV[7:0] RESP 19 ASSI200DEV[7:0] RESP 20 STRONGDEV[7:0] RESP 21 RDSPI[15:8] RESP 22 RDSPI[7:0]

58 Rev. 0.9

Page 59

RESP Bit Name Function

AN543

17MULTHINT

16MULTLINT

1 5 ISSIHINT

14ISSILINT

1 3 SNRHINT

Multipath Detect High.

0 = Indicates that multipath value has not exceeded the Multipath high threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD. 1 = Indicates that multipath value has exceeded the Multipath high threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD.

Multipath Detect Low.

0 = Indicates that multipath value has not fallen below the Multipath low threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD. 1 = Indicates that multipath value has fallen below the Multipath low threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD.

ISSI Detect High.

(Available in Si475x-A30 only) 0 = Indicates that ISSI has not exceeded the ISSI high threshold set by FM_RSQ_ISSI_HIGH_THRESHOLD. 1 = Indicates that ISSI has exceeded the ISSI high threshold set by FM_RSQ_ISSI_HIGH_THRESHOLD.

ISSI Detect Low.

(Available in Si475x-A30 only) 0 = Indicates that ISSI has not fallen below the ISSI low threshold set by FM_RSQ_ISSI_LOW_THRESHOLD. 1 = Indicates that ISSI has fallen below the ISSI low threshold set by FM_RSQ_ISSI_LOW_THRESHOLD.

SNR Detect High.

0 = Indicates that the received signal SNR has not exceeded the SNR high threshold set by FM_RSQ_SNR_HIGH_THRESHOLD 1 = Indicates that the received signal SNR has exceeded the SNR high threshold set by FM_RSQ_SNR_HIGH_THRESHOLD.

1 2 SNRLINT

SNR Detect Low.

0 = Indicates that the received signal SNR has not fallen below the SNR low threshold set by FM_RSQ_SNR_LOW_THRESHOLD. 1 = Indicates that the received signal SNR has fallen below the SNR low threshold set by FM_RSQ_SNR_LOW_THRESHOLD.

Rev. 0.9 59

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RESP Bit Name Function

1 1 RSSIHINT

1 0 RSSILINT

2 5 SNRREADY

2 4 RSSIREADY

BLTF

Reserved Values may vary.

RSSI Detect High.

0 = Indicates that the received signal RSSI has not exceeded the RSSI high threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD. 1 = Indicates that the received signal RSSI has exceeded the RSSI high threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD.

RSSI Detect Low.

0 = Indicates that the received signal RSSI has not fallen below the RSSI low threshold set by FM_RSQ_RSSI_LOW_THRESHOLD. 1 = Indicates that the received signal RSSI has fallen below the RSSI low threshold set by FM_RSQ_RSSI_LOW_THRESHOLD.

Band Limit.

Reports if a seek hits the band limit (WRAP = 0 in FM_START_SEEK) or wrapped to the original frequency (WRAP = 1).

The SNRREADY and RSSIREADY bits indicate that the RSSI/SNR have been read as a result of a tune command. If either one of these bits are 0 this indicates that either the metric is being measured (because a tune is in progress) or that the metric was not measured during tune because the station was invalidated before the metric could be measured. In the case where a metric was not measured during tune, the tune time RSQ status will read back as 0 for the unmeasured metric. The normal running time status for these metrics is not affected and will report normally.

0 = SNR measurement in progress (tune in progress) or not taken (tune completed). 1 = SNR measurement ready.

0 = RSSI measurement in progress (tune in progress) or not taken (tune completed).

1 = RSSI measurement ready.

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RESP Bit Name Function

2 3 Reserved Values may vary.

2 2 INJSIDE Injection side used.

0 = Low-side injection is being used 1 = High-side injection is being used

2 1 AFCRL Set if the AFC rails. AFC gets railed if FREQOFF >

FM_VALID_MAX_TUNE_ERROR.

2 0 VALID (Si475x-A20 and earlier)

Reports if the channel is valid based on the settings of: FM_VALID_RSSI_THRESHOLD, FM_VALID_SNR_THRESHOLD, FM_VALID_MAX_TUNE_ERROR

(Si475x-A30 and later) Reports if the channel is valid based on the settings of: FM_VALID_RSSI_THRESHOLD, FM_VALID_SNR_THRESHOLD, FM_VALID_MAX_TUNE_ERROR, FM_VALID_ASSI_THRESHOLD, FM_VALID_ISSI_THRESHOLD

3,4 15:0 READFREQ[15:0] Returns the currently tuned frequency.

5 7:0 FREQOFF[7:0] Signed frequency offset in units set by

FM_VALID_FREQOFF_SCALE (–128 to 126)

6 7:0 RSSI[7:0] Received Signal Strength indicator in dBµV

(–128 to 127)

7 7:0 SNR[7:0] RF SNR indicator in dB (–128 to 127).

8 7:0 ISSI[7:0] Image Signal Strength Indicator reports the image power

relative to carrier (–128 to 127). This metric is only valid when ATTUNE = 1. Only applicable to Si475x-A30 and later.

9 7:0 LASSI[7:0] Low side Adjacent (100 kHz) Channel Strength Indicator

reports the (Signal + Noise) power relative to the carrier.(–128 to 127)

10 7:0 HASSI[7:0] High side Adjacent (100 kHz) Channel Strength Indicator

reports the (Signal + Noise) power relative to the carrier.(–128 to 127)

11 7:0 MULT[7:0] Multipath Indicator.

(For Si475x-A20 and later) Range: 0–100% (ForSi475x-A10) Multipath = MULT/127 x 100% Range: 0–127

12 7:0 DEV[7:0] Frequency Deviation metric in kHz.

13, 14 15:0 Reserved Values may vary.

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RESP Bit Name Function

15 7:0 ASSI200[7:0] Adjacent Channel (±200 kHz) Strength Indicator reports

the (Signal + Noise) power relative to the carrier. This metric reports the sum of high and low adjacent channel strengths. (–128 to 127)

16 7:0 USN[7:0] Ultrasonic Noise Indicator in –dBFS (0 to 127). 127

corresponds to 127 dB down from full scale.

(Only applicable to Si475x-A30 and later) Pilot deviation in

17 7:0 PILOTDEV[7:0]

18 7:0 RDSDEV[7:0]

19 7:0 ASSI200DEV[7:0]

20 7:0 STRONGDEV[7:0]

21,22 15:0 RDSPI[15:0] (Only applicable to Si475x-A30 and later) RDS PI code.

units of 100 Hz. Range:0-127

(Only applicable to Si475x-A30 and later) RDS deviation in units of 100 Hz.

(Only applicable to Si475x-A30 and later) Adjacent Channel (±200 kHz) Deviation. Deviation is equal to ASSI200DEV x 1.5 kHz minus 12 kHz.

(Only applicable to Si475x-A30 and later) Deviation of very strong desired signals. This is an alternative to DEV, which can become erroneous in the presence of very strong signals. STRONGDEV is the weighted sum of FM mono/stereo (L + R) and stereo (L – R) deviation. Approximately, deviation in kHz = STRONGDEV x f(mod), where f(mod) is 5.55 kHz for mono signals, or 2.75 kHz for stereo signals.

Command 0x35 FM_ACF_STATUS

The FM_ACF_STATUS command returns status information about automatically-controlled features. This command returns the Soft Mute Attenuation, Channel Filter Bandwidth, HICUT cutoff frequency, HIBLEND cutoff frequency, and Stereo Separation associated with the desired channel. Stereo Separation will only be non-zero if the pilot indicator is set. If SMUTE bit is high, it indicates that audio is soft-muted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.

Command

Bit76543210

CMD 0x35

ARG1 0000000 ACFACK

ARG Bit Name Function

1 7:1 Reserved Always write 0000000.

1 0 ACFACK If set clears ACFINT and any ACF interrupts bits.

62 Rev. 0.9

Page 63

Response

Bit 7 6 5 4 3 2 1 0

AN543

STATUS

RESP1

RESP2 RESP3 RESP4 RESP5 RESP6 RESP7 RESP8

CTS ERR XX RSQINT RDSINT ACFINT STCINT

CHBWH_

INT

BLEND_

INT

HIBLEND_

INT

HICUT_

INT

CHBW_

INT

SOFTMUTE_

INT

XXXXXXX SMUTE

XXX SMATTN[4:0]

CHBW[7:0]

HICUT[7:0]

HIBLEND[7:0]

PILOT STBLEND[6:0]

LOWCUT[7:0]

Rev. 0.9 63

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RESP Bit Name Function

1 7:6 Reserved Values may vary.

(Available on Si475x-A40 only.)

1 5 CHBWH_INT

If set, indicates that the channel filter bandwidth is greater than the threshold set by FM_ACF_CHBW_THRESHOLD.

1 4 BLEND_INT

1 3 HIBLEND_INT

1 2 HICUT_INT

11CHBW_INT

1 0 SOFTMUTE_INT

2 7:1 Reserved Values may vary.

20 SMUTE

3 7:5 Reserved Values may vary.

34:0SMATTN[7:0]

4 7:0 CHBW[7:0]

57:0HICUT[7:0]

If set, indicates that stereo separation has crossed below the blend threshold set by FM_ACF_BLEND_THRESHOLD.

If set, indicates that the HIBLEND cutoff frequency is lower than the threshold as set by FM_ACF_HIBLEND_THRESHOLD.

If set, indicates that the HICUT cutoff frequency is lower than the threshold set by FM_ACF_HICUT_THRESHOLD.

If set, indicates that the Channel Filter Bandwidth is less than the threshold set by FM_ACF_CHBW_THRESHOLD.

If set, indicates that softmute attenuation has increased above the softmute threshold as set by ACF_SM_THRESHOLD.

0 = Audio is not soft muted. 1 = Audio is soft muted.

Soft mute attenuation level in dB. Range: 0–31.

Channel filter bandwidth in kHz. Range: 0–150.

LPR cutoff frequency in units of 100 Hz. Range: 10–180.

6 7:0 HIBLEND[7:0]

77 PILOT

7 6:0 STBLEND[6:0]

8 7:0 LOWCUT[7:0]

64 Rev. 0.9

LMR cutoff frequency in units of 100 Hz. Range: 10–180.

0 = Stereo pilot is not present. 1 = Stereo pilot is present.

Indicates stereo separation. STBLEND will only be non-zero if PILOT = 1. Range 0–100.

(Available in Si475x-A30 and later.) Lowcut cutoff frequency in units of 10 Hz. Only available if lowcut is enabled by the FM_LOWCUT_MIN_FREQ property. Range 1–100.

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Command 0x36 FM_RDS_STATUS (Si4751/53/55/57 Only)

The FM_RDS_STATUS command returns RDS information for current channel and reads an entry from the RDS FIFO. RDS information includes synch status, FIFO status, group data (blocks A, B, C, and D), and block errors corrected. Maximum RDS FIFO size is 25 groups. This command clears the RDSINT interrupt bit when INTACK bit in ARG1 is set, and, if MTFIFO is set, the entire RDS receive FIFO is cleared (FIFO is always cleared during FM_TUNE_FREQ or FM_SEEK_START). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode.

Command

Bit76543 2 1 0

CMD

ARG1 00000 STATUS_ONLY MTFIFO INTACK

ARG Bit Name Function

1 7:3 Reserved Always write 00000.

Status Only.

Determines if data should be removed from the RDS FIFO. 0 = Data is removed from RDS FIFO, and RDSFIFOUSED decre-

ments by one. Data in BLOCKA, BLOCKB, BLOCKC, BLOCKD,

12STATUS_ONLY

1 1 MTFIFO

10 INTACK

and BLE contain the oldest data in the RDS FIFO. 1 = Data is not removed from RDSFIFO, and the RDSFIFOUSED value stays the same. Data in BLOCKA, BLOCKB, BLOCKC, BLOCKD, BLE, PI, TP, PTY, and status contain the last valid data received for the current station.

Empty FIFO.

The FIFO will always be cleared during FM_TUNE_FREQ and FM_SEEK_START

0 = If FIFO not empty, read and remove oldest FIFO entry. 1 = Clear RDS Receive FIFO.

Interrupt Acknowledge.

0 = RDSINT status preserved. 1 = Clears RDSINT.

0x36

Rev. 0.9 65

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Response

Bit 7 6 5 4 3 2 1 0

STATUS

RESP1 XXX RDSTPPTYINT RDSPIINT X RDSSYNCINT RDSFIFOINT

RESP2 XXX TPPTYVALID PIVALID X RDSSYNC RDSFIFOLOST

RESP3 XX TP PTY[4:0]

RESP4 PI[15:8]

RESP5 PI[7:0]

RESP6 RDSFIFOUSED[7:0]

RESP7 BLEA[1:0] BLEB[1:0] BLEC[1:0] BLED[1:0]

RESP8 BLOCKA[15:8]

RESP9 BLOCKA[7:0]

RESP10 BLOCKB[15:8] RESP11 BLOCKB[7:0] RESP12 BLOCKC[15:8] RESP13 BLOCKC[7:0] RESP14 BLOCKD[15:8]

CTS ERR XX RSQINT RDSINT ACFINT STCINT

RESP15 BLOCKD[7:0] RESP16 IQSNR[7:0]

66 Rev. 0.9

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RESP Bit Name Function

1 7:5 Reserved Values may vary.

14RDSTPPTYINT

1 3 RDSPIINT 1 = PI (Program Identification) code has changed.

1 2 Reserved Values may vary.

1 1 RDSSYNCINT 1 = RDS synchronization has changed.

1 = TP (Traffic Program) flag and/or PTY (Program Type) code has changed.

AN543

1 0 RDSFIFOINT

2 7:5 Reserved Values may vary.

2 4 TPPTYVALID 1 = Indicates that TP flag and PTY code are valid.

2 3 PIVALID 1 = Indicates that PI code is valid.

2 2 Reserved Values may vary.

2 1 RDSSYNC 1 = RDS is currently synchronized.

2 0 RDSFIFOLOST

3 7:6 Reserved Values may vary.

3 5 TP Current channel’s TP flag if TPPTYVALID is set to 1.

3 4:0 PTY[4:0] Current channel's PTY code if TPPTYVALID is 1.

4,5 15:0 PI[15:0] Current channel’s PI code if PIVALID is set to 1.

6 7:0 RDSFIFOUSED[7:0]

7 7:6 BLEA[1:0]

1 = RDS was received and the RDS FIFO is full or has atleast FM_RDS_INTERRUPT_FIFO_COUNT entries.

1 = Indicates that one or more RDS groups have been discarded due to FIFO overrun since last call to FM_RDS_STATUS.

RDS FIFO Used.

Number of groups remaining in the RDS FIFO (0 if empty). If non-zero, BLOCKA-BLOCKD contain the oldest FIFO entry and RDSFIFOUSED decrements by one on the next call to RDS_FIFO_STATUS (assuming no RDS data received in the interim).

RDS Block A Corrected Errors.

0 = No errors. 1 = 1–2 bit errors detected and corrected. 2 = 3–5 bit errors detected and corrected. 3 = Uncorrectable.

7 5:4 BLEB[1:0]

7 3:2 BLEC[1:0]

RDS Block B Corrected Errors.

0 = No errors. 1 = 1–2 bit errors detected and corrected. 2 = 3–5 bit errors detected and corrected. 3 = Uncorrectable.

RDS Block C Corrected Errors.

0 = No errors. 1 = 1–2 bit errors detected and corrected. 2 = 3–5 bit errors detected and corrected. 3 = Uncorrectable.

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RESP Bit Name Function

RDS Block D Corrected Errors.

0 = No errors.

7 1:0 BLED[1:0]

1 = 1–2 bit errors detected and corrected. 2 = 3–5 bit errors detected and corrected. 3 = Uncorrectable.

8,9 15:0 BLOCKA[15:0]

10,11 15:0 BLOCKB[15:0]

12,13 15:0 BLOCKC[15:0]

14,15 15:0 BLOCKD[15:0]

16 7:0 IQSNR[7:0]

Block A group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block A data if STATUSONLY is 1.

Block B group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block B data if STATUSONLY is 1.

Block C group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block C data if STATUSONLY is 1.

Block D group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block D data if STATUSONLY is 1.

(Available in Si475x-A40 and later.) RDS I/Q SNR. Range: –128 to 127

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Command 0x37 FM_RDS_BLOCKCOUNT (Si4751/53/55/57 Only)

The FM_RDS_BLOCKCOUNT command returns RDS expected, received, and uncorrectable block statistic information. Reset info by setting CLEAR bit or sending FM_TUNE_FREQ or FM_SEEK_START commands. Once EXPECTED saturates at 65535, all other block count statistics will be frozen until the counts are cleared. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup mode.

Command

Bit76543210

CMD

ARG1 0000000 CLEAR

ARG Bit Name Function

1 7:1 Reserved Always write 0000000.

1 0 CLEAR

Response

Bit76543210

STATUS

RESP1 XXXXXXXX RESP 2 EXPECTED[15:8] RESP 3 EXPECTED[7:0] RESP 4 RECEIVED[15:8] RESP 5 RECEIVED[7:0]

CTS ERR XX RSQINT RDSINT ACFINT STCINT

Clears the block counts if set. The current block counts will be reported before they are cleared.

0x37

RESP 6 UNCORRECTABLE[15:8] RESP 7 UNCORRECTABLE[7:0]

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RESP Bit Name Function

1 7:0 Reserved Values may vary.

2,3 15:0 EXPECTED[15:0] Number of expected RDS blocks.

Number of received RDS blocks. Under ideal condi-

4,5 15:0 RECEIVED[15:0]

6,7 15:0 UNCORRECTABLE[15:0]

tions, EXPECTED and RECEIVED would be identical. The difference between these two numbers is the number of blocks lost.

Number of uncorrectable RDS blocks. These blocks have been received, but were found to have uncorrectable errors. The block error rate (BLER) is calculated by: BLER = (UNCORRECTABLE + (EXPECTED-RECEIVED)) / EXPECTED

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7.2.2. FM Receiver Properties

Property 0x0302 AUDIO_DE_EMPHASIS

The AUDIO_DE_EMPHASIS property sets the FM Receive deemphasis to 50 or 75 μs. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 75 μs.

Default: 0

AUDIO_DE_EMPHASIS

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0x0000 DE_EMPH

0x0000 0

Bit Name Function

15:1 Reserved Always write 0.

Sets the FM Receive de-emphasis to 50 or 75 μs. Default is 75 µs.

0 DE_EMPH

0=75µsec 1=50µsec

Property 0x0400 FM_SOFT_MUTE_MAX_ATTENUATION

The FM_SOFT_MUTE_MAX_ATTENUATION property sets the maximum attenuation in dB that will be applied by the softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 8

Units: dB

FM_SOFT_MUTE_MAX_ATTENUATION

1514131211109876543210

0x000 SMATTN[6:0]

0x000 0x08

Bit Name Function

15:7 Reserved Always write 0.

Sets the maximum attenuation in dB that will be applied by the softmute feature. Default is 8 dB.

6:0 SMATTN[6:0]

(Si475x-A20 and earlier) Range is 0-31. (Si475x-A30 and later) Range is 0–63 dB.

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Property 0x0401 FM_SOFT_MUTE_TRIGGER_THRESHOLD

The FM_SOFT_MUTE_TRIGGER_THRESHOLD property sets the RSSI/SNR threshold in dB to engage softmute. If USE_RSSI is set in FM_ACF_CONTROL_SOURCE property, then property 0x0401 refers to RSSI threshold. If USE_RSSI is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A40 and earlier, Default: 8

Si475x/5xC-A55, Default: 2

Units: dB

FM_SOFT_MUTE_TRIGGER_THRESHOLD

1514131211109876543210

SNR_SMTRGTH[7:0] RSSI_SMTRGTH[7:0]

0x00 0x02

Bit Name Function

15:8 SNR_SMTRGTH[7:0]

7:0 RSSI_SMTRGTH[7:0]

Sets the SNR threshold in dB to engage softmute, default is 0. Range is -127 ~ 127. This field is only available in Si475x/5xC-A55.

Sets the RSSI threshold in dB to engage softmute. Si475x/5xC-A55, Default is 2 dB Range is 0 to 15 dB for Si475x-A10 and –127 to 127 dB for later.

Si475x-A20 or

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Property 0x0402 FM_SOFT_MUTE_END_THRESHOLD

The FM_SOFT_MUTE_END_THRESHOLD property sets the SNR threshold in dB at which softmute attenuation will be set to its maximum value. When the SNR is at this level or lower, the audio attenuation will be set to FM_SOFT_MUTE_MAX_ATTENUATION. If USE_RSSI is set in the FM_ACF_CONTROL_SOURCE property, then property 0x0402 refers to the RSSI threshold. If USE_RSSI is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A40 and earlier, Default: 0

Si475x/5xC-A55, Default: -6

Units:dB

FM_SOFT_MUTE_END_THRESHOLD

1514131211109876543210

SNR_SMENDTH[7:0] RSSI_SMENDTH[7:0]

0x00 0xFA

Bit Name Function

Sets SNR threshold in dB to end the softmute, default is 0.

15:8 SNR_SMENDTH[7:0]

7:0 RSSI_SMENDTH[7:0]

Property 0x0403 FM_SOFT_MUTE_RELEASE_TIME

The FM_SOFT_MUTE_RELEASE_TIME property sets the maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 500

Units: ms

1514131211109876543210

Range is –127 ~ 127 This field is only available in Si475x/5xC-A55.

Sets the RSSI threshold in dBuV to end the softmute. Si475x/5xC-A55, Default is –6 dB. Si475x-A40 and earlier, default is 0. Range is 0 to 15 dB for Si475x-A10, and –127 to127 dB for Si475x-A20 or

later.

FM_SOFT_MUTE_RELEASE_TIME

RELEASE[15:0]

0x01F4

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Bit Name Function

Sets the maximum time in ms it takes to unmute the audio. Note that there

15:0 RELEASE[15:0]

Property 0x0404 FM_SOFT_MUTE_ATTACK_TIME

The FM_SOFT_MUTE_ATTACK_TIME property sets the maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier, Si475x-A40 and later: This property is not available

Units: ms

1514131211109876543210

will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage. Default is 500 ms. Range is 1–32767 ms.

FM_SOFT_MUTE_ATTACK_TIME

ATTACK[15:0]

0x0078

Bit Name Function

Sets the maximum time in ms it takes to mute the audio. Note that there will

15:0 ATTACK[15:0]

Property 0x0405 FM_SOFT_MUTE_MAX_ATTENUATION_AGC (Si4754/55/56/57 Only)

When AGC is engaged, the FM_SOFT_MUTE_MAX_ATTENUATION_AGC property sets the maximum attenuation in dB that will be applied by the RSSI/SNR softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 0x0080

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/ disengage. Default is 120 ms. Range is 1–32767 ms.

FM_SOFT_MUTE_MAX_ATTENUATION_AGC

0x00 IGNORE_AGC SMATTN[6:0]

0x00 1 0x00

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Bit Name Function

15:8 Reserved Always write to 0.

Selects which set of properties control softmute when AGC is engaged.

7 IGNORE_AGC

6:0 SMATTN[6:0]

Property 0x0406 FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC (Si4754/55/56/57 Only)

When AGC is engaged, the FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC property sets the RSSI/SNR threshold in dB to engage softmute. If USE_RSSI bit is set in FM_ACF_CONTROL_SOURCE property (0x1306), then this property refers to RSSI threshold. If USE_RSSI bit is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

0 = Use properties 0x0405-0x0409 when the AGC is engaged, and properties 0x0400-0x0404 otherwise.

1 = Always use only properties 0x0400-0x0404.

When AGC is engaged, sets the maximum attenuation in dB that will be applied by the RSSI/SNR softmute feature. Default is 0 dB. Range is 0– 63 dB.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 8

Units: dB

FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC

1514131211109876543210

0x00 SMTRGTH_AGC[7:0]

0x00 0x08

Bit Name Function

15:8 Reserved Always write to 0.

7:0 SMTRGTH_AGC[7:0]

When AGC is engaged, sets the RSSI/SNR threshold in dB to engage softmute. Default is 8 dB. Range is –127 to 127 dB.

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Property 0x0407 FM_SOFT_MUTE_END_THRESHOLD_AGC (Si4754/55/56/57 Only)

When AGC is engaged, the FM_SOFT_MUTE_END_THRESHOLD_AGC property sets the RSSI/SNR threshold in dB at which softmute attenuation will be set to its maximum value. When the RSSI/SNR is at this level or lower, the audio attenuation will be set to FM_SOFT_MUTE_MAX_ATTENUATION_AGC. If USE_RSSI bit is set in FM_ACF_CONTROL_SOURCE property (0x1306), then this property refers to RSSI threshold. If USE_RSSI bit is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 0

Units: dB

FM_SOFT_MUTE_END_THRESHOLD_AGC

1514131211109876543210

0x00 SMTRGTH_AGC[7:0]

0x00 0x08

Bit Name Function

15:8 Reserved Always write to 0.

7:0 SMTRGTH_AGC[7:0]

Property 0x0408 FM_SOFT_MUTE_RELEASE_TIME_AGC (Si4754/55/56/57 Only)

When AGC is engaged, the FM_SOFT_MUTE_RELEASE_TIME_AGC property sets maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 500

Units: ms

1514131211109876543210

When AGC is engaged, sets the RSSI/SNR threshold in dB to engage softmute. Default is 8 dB. Range is –127 to 127 dB.

FM_SOFT_MUTE_RELEASE_TIME_AGC

RELEASE_AGC[15:0]

0x01F4

Bit Name Function

Sets the maximum time in ms it takes to unmute the audio. Note that there

15:0 RELEASE_AGC[15:0]

76 Rev. 0.9

will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage. Default is 500 ms. Range is 1–32767 ms.

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Property 0x0409 FM_SOFT_MUTE_ATTACK_TIME_AGC (Si4754/55/56/57 Only)

When AGC is engaged, the FM_SOFT_MUTE_ATTACK_TIME_AGC property sets maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier, Si475x-A40 and later: This property is not available

Si475x-A30, Default: 120

Units: ms

FM_SOFT_MUTE_ATTACK_TIME_AGC

1514131211109876543210

ATTACK_AGC[15:0]

0x0078

Bit Name Function

Sets the maximum time in ms it takes to unmute the audio. Note that

15:0 ATTACK_AGC[15:0]

there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage.Default is 120 ms. Range is 1–32767 ms.

Property 0x040A FM_SOFT_MUTE_USN_LIMITS

The FM_SOFT_MUTE_USN_LIMITS property sets the values of USN for which audio is minimally and maximally muted by USN-based soft mute. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Note: USN will generally be negative under signal conditions where soft mute is desirable. The recommended setting is

0xCEE2 (YMIN = –50, YMAX = –30).

Si475x-A20 and earlier, Si475x-A40 and later: This property is not available

Si475x-A30, Default: 0x060E

Units: ms

FM_SOFT_MUTE_USN_LIMITS

1514131211109876543210

YMIN[7:0] YMAX[7:0]

0x06 0x0E

Bit Name Function

15:8 YMIN[7:0]

Sets the value of USN that causes minimum attenuation for USNbased soft mute. Default is 6. Range is –127 to 127.

7:0 YMAX[7:0]

Sets the value of USN that causes maximum attenuation for USN-based soft mute. Default is 14. Range is –127 to 127.

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Property 0x040B FM_SOFT_MUTE_USN_ATTENUATION

The FM_SOFT_MUTE_USN_ATTENUATION property sets the limits for soft mute attenuation when driven by USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier, Si475x-A40 and later: This property is not available.

Si475x-A30, Default: 0x0000

Units: dB

FM_SOFT_MUTE_USN_ATTENUATION

1514131211109876543210

YMIN[7:0] YMAX[7:0]

0x00 0x00

Bit Name Function

15:8 YMIN[7:0]

7:0 YMAX[7:0]

Property 0x040C FM_SOFT_MUTE_USN_ATTACK_TIME

The FM_SOFT_MUTE_USN_ATTACK_TIME property sets maximum time in ms it takes to mute the audio based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier, Si475x-A40 and later: This property is not available.

Si475x-A30, Default: 0x0080

Units: ms

FM_SOFT_MUTE_USN_ATTACK_TIME

1514131211109876543210

Sets the minimum attenuation in dB for USN-based soft mute. Default is 0. Range is 0–63.

Sets the maximum attenuation in dB for USN-based soft mute. Default is 0. Range is 0–63.

ATTACK[15:0]

0x0080

Bit Name Function

Sets the USN-based soft mute attack time in ms. Note that there

15:0 ATTACK[15:0]

78 Rev. 0.9

will be 16 ms of filter delay for USN metric before softmute can engage/disengage. Default is 128. Range is 1–32767.

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Property 0x040D FM_SOFT_MUTE_USN_RELEASE_TIME

The FM_SOFT_MUTE_USN_RELEASE_TIME property sets maximum time in ms it takes to unmute the audio based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier, Si475x-A40 and later: This property is not available

Si475x-A30, Default: 0x0100

Units: ms

FM_SOFT_MUTE_USN_RELEASE_TIME

1514131211109876543210

RELEASE[15:0]

0x0004

Bit Name Function

Sets the USN-based soft mute release time in ms. Note that there will be 16 ms of filter delay for USN metric before softmute

15:0 RELEASE[15:0]

can engage/disengage. Default is 256. Range is 1–32767.

Property 0x040E FM_SOFT_MUTE_ASSI200DEV_LIMITS

The FM_SOFT_MUTE_ASSI200DEV_LIMITS property sets the ASSI200DEV threshold to engage softmute and sets the ASSI200DEV threshold at which softmute attenuation will be set to its maximum value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A10 and earlier: Range: 4–248 ms.

Si475x-A20 and later: Range is 4–4096 ms.

FM_SOFT_MUTE_ASSI200DEV_LIMITS

1514131211109876543210

SMTRGTH_ASSI200DEV[7:0] SMENDTH_ASSI200DEV[7:0]

0x33 0x5A

Bit Name Function

15:8 SMTRGTH_ASSI200DEV[7:0]

7:0 SMENDTH_ASSI200DEV[7:0]

Sets the ASSI200DEV threshold to engage softmute. Default is

51. Range is 0 to 150.

Sets the ASSI200DEV threshold at which softmute attenuation will be set to its maximum value. Default is 90. Range is 0 to 150.

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Property 0x040F FM_SOFT_MUTE_ASSI200DEV_ATTENUATION

The FM_SOFT_MUTE_ASSI200DEV_ATTENUATION property sets the maximum attenuation in dB that will be applied by the ASSI200DEV softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 0

Units: dB

FM_SOFT_MUTE_ASSI200DEV_ATTENUATION

1514131211109876543210

0x00 SMATTN_ASSI200DEV[6:0]

0x00 0x00

Bit Name Function

15:8 Reserved Always write to 0.

Sets the maximum attenuation in dB that will be applied by the

7:0 SMATTN_ASSI200DEV[6:0]

ASSI200DEV softmute feature. Default is 0 dB. Range is 0– 63 dB.

Property 0x0410 FM_SOFT_MUTE_ASSI200DEV_ATTACK_TIME

The FM_SOFT_MUTE_ASSI200DEV_ATTACK_TIME property sets maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 128

Units: ms

FM_SOFT_MUTE_ASSI200DEV_ATTACK_TIME

1514131211109876543210

ATTACK_ASSI200DEV[15:0]

0x0080

Bit Name Function

Sets the maximum time in ms it takes to mute the audio.

15:0 ATTACK_ASSI200DEV[15:0]

Note that there will be 16 ms of filter delay for the ASSI200DEV metric before softmute can engage/disengage. Default is 128 ms. Range is 1–32767 ms.

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Property 0x0411 FM_SOFT_MUTE_ASSI200DEV_RELEASE_TIME

The FM_SOFT_MUTE_ASSI200DEV_RELEASE_TIME property sets maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 256

Units: ms

FM_SOFT_MUTE_ASSI200DEV_RELEASE_TIME

1514131211109876543210

RELEASE_ASSI200DEV[15:0]

0x0100

Bit Name Function

Sets the maximum time in ms it takes to unmute the audio.

15:0 RELEASE_ASSI200DEV[15:0]

Note that there will be 16 ms of filter delay for the ASSI200DEV metric before softmute can engage/disengage.

Default is 256 ms. Range is 1–32767 ms.

Property 0x0700 FM_AGC_FE_CONFIG

The FM_AGC_FE_CONFIG property specifies the input path for the RF signal and other FE configuration options. This property should only be set before the first tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Changes to this property take effect after the next tune is completed.

Default: 0x0080

FM_AGC_FE_CONFIG

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0x00 FMLNAZ 1000 INPUTSELECT[3:0]

0x00 0 1000 0x0

Bit Name Function

15:9 Reserved Always write 0.

0 = LNA input impedance is 50

8FMLNAZ

7:4 Reserved Always write 1000.

3:0 INPUTSELECT[3:0]

1 = LNA input impedance is 100 ers splitting a single antenna signal) (Si4754/55/56/57 only)

0 = Received signal comes into FMI pin, out FMO and then the mixer pin.

1 = Received signal comes directly into the mixer at the FMXIP/ FMIN pins.

.(Normal Operation)

(Loop-through mode: two receiv-

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Property 0x0701 FM_AGC_PD_CONFIG

The FM_AGC_PD_CONFIG property specifies behavior of the FM peak detectors and attenuators. This property should only be set before the first tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Changes to this property take effect after the next tune is completed.

Default: 0x0270

FM_AGC_PD_CONFIG

151413 12 1110 9 8 765432 1 0

0x0 LNA_MODE 00100 MIXER_PD[2:0] 0x00 LNA_PD[1:0]

0x0 0 00100 0x7 0x00 0x00

Bit Name Function

15:13 Reserved Always write 0.

LNA_MODE default: 0 This property only used when the LNA gain and one or both of the attenuators are controlled by the same peak

12 LNA_MODE

detector. 0 = Reduce LNA gain and then attenuate with FMAGC1/2. 1 = Attenuate with FMAGC1/2 and then reduce LNA gain.

11:7 Reserved Always write 00100.

MIXER_PD[2:0] default: 0x7. 0 = Peak detector not used. 1 = Controls FMAGC1. 2 = Controls FMAGC2.

6:4 MIXER_PD[2:0]

3:2 Reserved Always write 0.

1:0 LNA_PD[1:0]

3 = Controls FMAGC1 and FMAGC2. 4 = Controls LNA gain. 5 = Controls LNA gain and FMAGC1. 6 = Controls LNA gain and FMAGC2. 7 = Controls LNA gain, FMAGC1 and FMAGC2.

LNA_PD[1:0] default: 0x0 0 = Peak detector not used 1 = Controls FMAGC1 2 = Controls FMAGC2 3 = Controls FMAGC1 and FMAGC2

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Property 0x0702 FM_LNA_AGC_ATTACK_MS

The FM_LNA_AGC_ATTACK_MS property sets the number of milliseconds the wide-band RF high-peak detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3 to 5 ms. If the peak detector trips, the internal counter is incremented by 4 ms.The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 4

Units: ms

FM_LNA_AGC_ATTACK_MS

1514131211109876543210

RF_AGC_ATTACK_MS[15:0]

0x0004

Bit Name Function

Number of milliseconds the wideband RF highpeak detector must be exceeded before atten-

15:0 RF_AGC_ATTACK_MS[15:0]

uating the appropriate block. Default is 4 ms.

Si475x-A10 and earlier: Range: 4–248 ms. Si475x-A20 and later: Range is 4–4096 ms.

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Property 0x0703 FM_LNA_AGC_RELEASE_MS

The FM_LNA_AGC_RELEASE_MS property sets the number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled once every 3 to 5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 80

Units: ms

FM_LNA_AGC_RELEASE_MS

1514131211109876543210

RF_AGC_RELEASE_MS[15:0]

0x0050

Bit Name Function

15:0 RF_AGC_RELEASE_MS[15:0]

Number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. Default is 80 ms

Si475x-A10 and earlier: Range: 4–248 ms. Si475x-A20 and later: Range is 4–4096 ms.

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Property 0x0704 FM_LNA_AGC_PD_THRESHOLD

The FM_LNA_AGC_PD_THRESHOLD property sets the high threshold and hysteresis for the LNA peak detector. The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB below the high threshold the level must drop before the AGC decreases attenuation. It is possible to decrease the likelihood of intermod break-in by decreasing the peak detector threshold from the default and it is possible to decrease the likelihood of desensitization by increasing the peak detector threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 0x4F05

FM_LNA_AGC_PD_THRESHOLD

1514131211109876543210

HIGH[7:0] HYST[7:0]

0x4F 0x05

Bit Name Function

Sets the level in dBµV at which AGC increases attenuation HIGH[7:0] Range: 73–87 73 = 73 dBµV 75 = 75 dBµV

15:8 HIGH[7:0]

7:0 HYST[7:0]

77 = 77 dBµV 79 = 79 dBµV 81 = 81 dBµV 83 = 83 dBµV 85 = 85 dBµV 87 = 87 dBµV

Sets how many dB below the high threshold the level must drop before the AGC decreases attenuation.

HYST[7:0] Range: 3–6 3 = 3 dB 4 = 4 dB 5 = 5 dB 6 = 6 dB

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Property 0x0705 FM_MIXER_AGC_ATTACK_MS

The FM_MIXER_AGC_ATTACK_MS property sets the number of milliseconds the wideband mixer high-peak detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3–5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A40 and earlier, Default: 4

Si475x/5xC-A55, Default: 248

Units: ms

FM_MIXER_AGC_ATTACK_MS

1514131211109876543210

MIX_AGC_ATTACK_MS[15:0]

0x00F8

Bit Name Function

15:0 MIX_AGC_ATTACK_MS[15:0]

Number of milliseconds the wideband RF highpeak detector must be exceeded before attenuating the appropriate block. Si475x/5xC-A55, Default is 248 ms

Si475x-A10 and earlier: Range: 4–248 ms Si475x-A20 and later: Range is 4–4096 ms

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Property 0x0706 FM_MIXER_AGC_RELEASE_MS

The FM_MIXER_AGC_RELEASE_MS property sets the number of milliseconds the wideband mixer low-peak detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled once every 3–5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 80

Units: ms

FM_MIXER_AGC_RELEASE_MS

1514131211109876543210

MIX_AGC_RELEASE_MS[15:0]

0x0050

Bit Name Function

15:0 MIX_AGC_RELEASE_MS[15:0]

Number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. Default is 80 ms

Si475x-A10 and earlier: Range: 4–248 ms. Si475x-A20 and later: Range is 4–4096 ms.

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Property 0x0707 FM_MIXER_AGC_PD_THRESHOLD

The FM_MIXER_AGC_PD_THRESHOLD property sets the high threshold and hysteresis for the mixer peak detector below the high threshold the level must drop before the AGC decreases attenuation. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 0x5103

. The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB

FM_MIXER_AGC_PD_THRESHOLD

1514131211109876543210

HIGH[7:0] HYST[7:0]

0x51 0x03

Bit Name Function

Sets the level in dBµV at which AGC increases attenuation. HIGH[7:0]: Range 79–93. 79 = 79 dBµV. 81 = 81 dBµV.

15:8 HIGH[7:0]

7:0 HYST[7:0]

83 = 83 dBµV. 85 = 85 dBµV. 87 = 87 dBµV. 89 = 89 dBµV. 91 = 91 dBµV. 93 = 93 dBµV.

Sets how many dB below the high threshold the level must drop before the AGC decreases attenuation.

HYST[7:0] - Range: 3–6. 3 = 3 dB. 4 = 4 dB. 5 = 5 dB. 6 = 6 dB.

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Property 0x0710 FM_AGC_OVERRIDE

The FM_AGC_OVERRIDE property overrides the AGC setting by disabling the AGC and forcing the gain to be maximum. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Note: In Si475x-A30 only, property FM_AGC_PD_CONFIG should be set to 0x0000 when overriding the AGC with the

FM_AGC_OVERRIDE property. Doing so removes the automatic AGC from peak detector control. Failure to set FM_AGC_PD_CONFIG when using FM_AGC_OVERRIDE could lead to a conflict which locks the tuner following an FM_TUNE_FREQ command.

Default: 0x0000

FM_AGC_OVERRIDE

1514131211109876543210

0x000 AGC_OVERRIDE[5:0]

0x000 0x000

Bit Name Function

15:6 Reserved Always write 0.

AGC_OVERRIDE selects whether the AGC is enabled or disabled.

5:0 AGC_OVERRIDE[5:0]

0 = AGC is enabled. 0x3F = AGC is disabled and set to maximum gain.

Property 0x071B FM_AGC_RSSI_OFFSET

The FM_AGC_RSSI_OFFSET property sets the value of the offset applied to the RSSI value in order to account for the front-end gain/loss due to the AGC. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A10 and before: This property is not available

Si475x-A20 and later, Default: 0

Units: dB

FM_AGC_RSSI_OFFSET

1514131211109876543210

OFFSET[7:0] RSVD[7:0]

0x00 0x00

Bit Name Function

Sets the RSSI offset value to take into account front-end gain/loss.

15:8 OFFSET[7:0]

7:0 Reserved Always write 0.

Default is 0. Range is –128 to 127.

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Property 0x071C FM_MIXER_AGC_PD_THRESHOLD_MAX (Si4754/55/56/57 Only)

The FM_MIXER_AGC_PD_THRESHOLD_MAX property sets the maximum threshold for the mixer peak detector when keyed AGC is engaged. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30/A40, Default: 85

Si475x/5xC-A55, Default: 89

FM_MIXER_AGC_PD_THRESHOLD_MAX

1514131211109876543210

0x00 MAX_KEY[7:0]

0x00 0x59

Bit Name Function

15:8 Reserved Always write to 0.

Sets the maximum level in dBuV at which AGC increases attenuation.

MAX_KEY [7:0]: Range 79–93 79 = 79 dBµV. 81 = 81 dBµV.

7:0 MAX_KEY[7:0]

83 = 83 dBµV. 85 = 85 dBµV. 87 = 87 dBµV. 89 = 89 dBµV. 91 = 91 dBµV. 93 = 93 dBµV Si475x/5xC-A55, Default is 89 dBµV.

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Property 0x071D FM_AGC_RSSI_MIXER_KEY (Si4754/55/56/57 Only)

The FM_AGC_RSSI_MIXER_KEY property sets the RSSI threshold at which the mixer keyed AGC begins to lower or raise the peak detector threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available.

Si475x-A30 and later, Default: 0x140E

FM_AGC_RSSI_MIXER_KEY

1514131211109876543210

KEY_HIGH_THR[7:0] KEY_LOW_THR[7:0]

0x14 0x0E

Bit Name Function

Sets the RSSI threshold at which the mixer keyed AGC begins to

15:8 KEY_HIGH_THR[7:0]

lower the peak detector threshold. Default is 20 dB. Range: –128 to 127 dB.

Sets the RSSI threshold at which the mixer keyed AGC begins to

7:0 KEY_LOW_THR[7:0]

Property 0x1006 FM_SEEK_TUNE_CHBW_HOLD_TIME

The FM_SEEK_TUNE_CHBW_HOLD_TIME property sets the length of time Channel Filter Bandwidth is held at specified value after Seek or Tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A10: This property is not available.

Si475x-A20: This feature is not available. Do not write to this property.

Si475x-A30 and later, Default: 80

Units: ms

FM_SEEK_TUNE_CHBW_HOLD_TIME

1514131211109876543210

raise the peak detector threshold. Default is 14 dB. Range: –128 to 127 dB.

CHBW_HOLD_TIME[15:0]

0x0050

Bit Name Function

15:0 CHBW_HOLD_TIME[15:0]

Sets the length of time Channel Filter Bandwidth is held at specified value after Seek or Tune. Default is 80ms. Range is 4-1000.

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Property 0x1007 FM_TUNE_CHBW

The FM_TUNE_CHBW property sets the maximum Channel Filter Bandwidth to allow during normal tune. Narrower Channel Filter Bandwidth could be used based on RSSI, HASSI, LASSI, and ASSI200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 80 Units: kHz

FM_TUNE_CHBW

1514131211109876543210

0x00 TUNE_CHBW[7:0]

0x00 0x50

Bit Name Function

15:8 Reserved Always write to 0.

Sets the maximum Channel Filter Bandwidth to allow during nor-

7:0 TUNE_CHBW[7:0]

mal tune. Narrower Channel Filter Bandwidth could be used based on RSSI, HASSI, LASSI, and ASSI200. Default is 80 kHz. Range is 0–150.

Property 0x1008 FM_TUNE_AF_CHBW (Si4754/55/56/57 Only)

The FM_TUNE_AF_CHBW property sets the Channel Filter Bandwidth during the AF tune/check. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Note: With Si475x-A40 defaults, the RSSI metric value for AF Check settles within 2 ms. To qualify additional metrics (SNR,

Multipath, USN, LASSI, HASSI, ASSI200) users should set Property 0x2007 FM_VALID_AF_TIME to 0x0005 (5 ms) and Property 0x1008 FM_TUNE_AF_CHBW to 0x0050 (80 kHz).

Si475x-A20 and earlier: This property is not available Si475x-A30 and A40, Default: 150

Si475x/5xC-A55, Default: 80

Units: kHz

FM_TUNE_AF_CHBW

1514131211109876543210

0x00 TUNE_AF_CHBW[7:0]

0x00 0x50

Bit Name Function

15:8 Reserved Always write to 0.

7:0 TUNE_AF_CHBW[7:0]

Sets the maximum Channel Filter Bandwidth to allow during AF Si475x/5xC-A55, Default is 80 kHz. Range is

0–150.

tune.

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Property 0x1100 FM_SEEK_BAND_BOTTOM

The FM_SEEK_BAND_BOTTOM property sets the bottom of the FM band for seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 8750

Units: 10 kHz

FM_SEEK_BAND_BOTTOM

1514131211109876543210

FMSKFREQL[15:0]

0x222E

Bit Name Function

Sets the bottom of the FM band for seek. Default is 8750. Range: 6400–10800, 64.0 MHz to 108.0 MHz.

15:0 FMSKFREQL[15:0]

Range: 8750–10790, Worldwide FM excluding Japan. Range: 6580–7400, OIRT FM. Range: 7600–9000, Japan FM.

Property 0x1101 FM_SEEK_BAND_TOP

The FM_SEEK_BAND_TOP property sets the top of the FM band for seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A40 and earlier, Default: 10790

Si475x/5xC-A55, Default:10800

Units: 10 kHz

FM_SEEK_BAND_TOP

1514131211109876543210

FMSKFREQH[15:0]

0x2A30

Bit Name Function

Sets the top of the FM band for seek. Si475x/5xC-A55 Default is 10800.

15:0 FMSKFREQH[15:0]

Range: 6400–10800, 64.0 MHz to 108.0 MHz. Range: 8750–10790, Worldwide FM excluding Japan. Range: 6580–7400,

OIRT FM. Range: 7600–9000, Japan FM.

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Property 0x1102 FM_SEEK_FREQUENCY_SPACING

The FM_SEEK_FREQUENCY_SPACING property selects frequency spacing for FM seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 100 kHz.

Default: 10

Units: 10 kHz

FM_SEEK_FREQUENCY_SPACING

1514131211109876543210

0x000 FMSKSPACE[4:0]

0x000 0x0A

Bit Name Function

15:5 Reserved Always write 0.

4:0 FMSKSPACE[4:0]

Selects frequency spacing for FM seek. Default is 10. Range is 1–31.

Property 0x1104 FM_SEEK_CHBW

The FM_SEEK_CHBW property sets the Channel Filter Bandwidth during seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Si475x-A20 and earlier: This property is not available. Si475x-A30 and A40, Default: 110

Si475x/5xC-A55, Default: 80

Units: kHz

FM_SEEK_CHBW

1514131211109876543210

0x00

Bit Name Function

15:8 Reserved Always write to 0.

Sets the maximum Channel Filter Bandwidth to allow during seek.

7:0 SEEK_CHBW[7:0]

Si475x/5xC-A55,

Recommended value for 50 or 100 kHz spacing is 80 kHz. mended value for 200 kHz spacing is 110 kHz.

Default is 80 kHz. Range is 0–150.

SEEK_CHBW[7:0]

0x50

Recom-

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Property 0x1200 FM_RSQ_INTERRUPT_SOURCE

The FM_RSQ_INTERRUPT_SOURCE property configures interrupt related to Received Signal Quality metrics. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 0

FM_RSQ_INTERRUPT_SOURCE

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0x00 MULTHINT MULTLINT ISSIHINT

0x00 0 0 0

ISSILINT

Bit Name Function

15:8 Reserved Always write 0.

0: Disable Interrupt.

7MULTHINT

1:Enable interrupt if Multipath level goes above the threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD.

0: Disable Interrupt.

6MULTLINT

1: Enable interrupt if Multipath level falls below the threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD.

0: Disable Interrupt.

5 ISSIHINT

1: Enable interrupt if ISSI goes above the threshold set by FM_RSQ_ISSI_HIGH_THRESHOLD.

0: Disable Interrupt.

4 ISSILINT

1: Enable interrupt if ISSI falls below the threshold set by FM_RSQ_ISSI_LOW_THRESHOLD.

0: Disable Interrupt.

3 SNRHINT

1: Enable interrupt if SNR goes above the threshold set by FM_RSQ_SNR_HIGH_THRESHOLD.

0: Disable Interrupt.

2SNRLINT

1: Enable interrupt if SNR falls below the threshold set by FM_RSQ_SNR_LOW_THRESHOLD.

0: Disable Interrupt.

1 RSSIHINT

1: Enable interrupt if RSSI goes above the threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD.

0: Disable Interrupt.

0 RSSILINT

1: Enable interrupt if RSSI falls below the threshold set by FM_RSQ_RSSI_LOW_THRESHOLD.

SNRHINT SNRLINT RSSIHINT RSSILINT

00 0 0

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Property 0x1201 FM_RSQ_SNR_HIGH_THRESHOLD

The FM_RSQ_SNR_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 127

Units: dB

FM_RSQ_SNR_HIGH_THRESHOLD

1514131211109876543210

0x00 SNRH[7:0]

0x00 0x7F

Bit Name Function

15:8 Reserved Write 0 for (+) values and 0xFF for (–) values.

7:0 SNRH [7:0]

Sets the high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. Default is 127 dB. Range is –128 to 127 in steps of 1 dB.

Property 0x1202 FM_RSQ_SNR_LOW_THRESHOLD

The FM_RSQ_SNR_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: –128

Units: dB

FM_RSQ_SNR_LOW_THRESHOLD

1514131211109876543210

0xFF SNRL[7:0]

0xFF 0x80

Bit Name Function

15:8 Reserved Write 0 for (+) values and 0xFF for (–) values.

7:0 SNRL [7:0]

Sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. Default is –128 dB. Range is –128 to 127 in steps of 1 dB.

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Property 0x1203 FM_RSQ_RSSI_HIGH_THRESHOLD

The FM_RSQ_RSSI_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if RSSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 127

Units: dBµV

FM_RSQ_RSSI_HIGH_THRESHOLD

1514131211109876543210

0x00 RSSIH[7:0] 0x00 0x7F

Bit Name Function

15:8 Reserved Write 0 for (+) values and 0xFF for (–) values.

7:0 RSSIH [7:0]

Property 0x1204 FM_RSQ_RSSI_LOW_THRESHOLD

The FM_RSQ_RSSI_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: –128

Units: dBµV

1514131211109876543210

0xFF RSSIL[7:0]

0xFF 0x80

Bit Name Function

15:8 Reserved Write 0 for (+) values and 0xFF for (–) values.

7:0 RSSIL [7:0]

Sets high threshold, which triggers the RSQ interrupt if the RSSI is above this threshold. Default is 127 dBµV. Range is –128 to 127 in steps of 1 dB.

FM_RSQ_RSSI_LOW_THRESHOLD

Sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. Default is –128 dBµV. Range is –128 to 127 in steps of 1 dB.

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Property 0x1205 FM_RSQ_ISSI_HIGH_THRESHOLD

The FM_RSQ_ISSI_HIGH_THRESHOLD property sets the Image Signal Strength Indicator high threshold, which triggers the RSQ interrupt if the ISSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 127

FM_RSQ_RSSI_LOW_THRESHOLD

1514131211109876543210

0x00 HIGH[7:0]

0x00 0x7F

Bit Name Function

15:8 Reserved Always write 0.

7:0 HIGH[7:0]

High threshold for ISSI interrupt in dBr relative to the desired signal. Default is 127 dBr. Range is –128 to 127.

Property 0x1206 FM_RSQ_ISSI_LOW_THRESHOLD

The FM_RSQ_ISSI_LOW_THRESHOLD property sets the Image Signal Strength Indicator low threshold, which triggers the RSQ interrupt if the ISSI is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: –128

FM_RSQ_ISSI_LOW_THRESHOLD

1514131211109876543210

0x00 LOW[7:0]

0x00 0x80

Bit Name Function

15:8 Reserved Always write 0.

7:0 LOW[7:0]

Low threshold for ISSI interrupt in dBr relative to the desired signal. Default is –128 dBr. Range is –128 to 127.

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Property 0x1207 FM_RSQ_MULTIPATH_HIGH_THRESHOLD

The FM_RSQ_MULTIPATH_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if Multipath is above this threshold. Multipath is a measure of AM modulation and can exceed 100%. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 127

FM_RSQ_MULTIPATH_HIGH_THRESHOLD

1514131211109876543210

0x000 MULTH[6:0]

0x000 0x7F

Bit Name Function

15:7 Reserved Always write 0.

6:0 MULTH [6:0]

Sets the high threshold, which triggers the RSQ interrupt if Multipath is above this threshold. Default is 127. Range is 0–127.

Property 0x1208 FM_RSQ_MULTIPATH_LOW_THRESHOLD

The FM_RSQ_MULTIPATH_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if Multipath is below this threshold. Multipath is a measure of AM modulation and can exceed 100%. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 0

FM_RSQ_MULTIPATH_LOW_THRESHOLD

1514131211109876543210

0x000 MULTL[6:0]

0x000 0x00

Bit Name Function

15:7 Reserved Always write 0.

6:0 MULTL[6:0]

Sets low threshold, which triggers the RSQ interrupt if Multipath is below this threshold. Default is 0. Range is 0–127.

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Property 0x1300 FM_ACF_INTERRUPT_SOURCE

The FM_ACF_INTERRUPT_SOURCE property enables the ACF interrupt sources. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode.

Default: 0

FM_ACF_INTERRUPT_SOURCE

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0x000

Bit Name Function

15:6 Reserved Always write 0.

5 CHBWH_INT

4BLEND_INT

3 HIBLEND_INT

CHBWH_INT BLEND_INT HIBLEND_INT HICUT_INT CHBW_INT SOFTMUTE_INT

00 0 00 0

(Available on Si475x-A40 only) When set, enables the Channel Filter Bandwidth High interrupt. Default is 0. 0 = The Channel Bandwidth interrupt is disabled 1 = The Channel Bandwidth interrupt is enabled

When set, enables the blend interrupt. Default is 0. 0 = The blend interrupt is disabled. 1 = The blend interrupt is enabled.

When set, enables the HIBLEND interrupt. Default is 0. 0 = The HIBLEND interrupt is disabled. 1 = The HIBLEND interrupt is enabled.

2 HICUT_INT

1 CHBW_INT

0 SOFTMUTE_INT

When set, enables the HICUT interrupt. Default is 0. 0 = The HICUT interrupt is disabled. 1 = The HICUT interrupt is enabled.

When set, enables the Channel Filter Bandwidth Interrupt. Default is 0. 0 = The Channel Filter Bandwidth interrupt is disabled. 1 = The Channel Filter Bandwidth interrupt is enabled.

When set, enables the softmute interrupt. Default is 0. 0 = The softmute interrupt is disabled. 1 = The softmute interrupt is enabled.

100 Rev. 0.9