ST STFPC311 User Manual

Features

■ IC front panel controller/driver

■ Timing power standby management controller

■ IC power supply from 3.3V (V

■ Integrated VFD driver and controller

■ Infrared (IR) Remote Control (RC) Decoder

(Philips or NEC format)

■ Drives many display modes (12 segments/16

digits to 20 segments/8 digits)

■ High voltage outputs (V

■ No external resistors necessary for driver

DD

outputs (P-channel open- drain with pull-down resistor outputs)

■ Key scanning (up to 12mm x 2mm matrix)

■ Led ports (4 channels, 20mA, max)

■ Serial interface (STB, CLK, D

communication protocol

■ Dimming circuit (adjustable up to 8 steps)

■ Supports auto-increment of display digit, which

lightens the load on the MCU

■ Programmable 8 hot keys for the IR remote

control command

■ Programmable 8 hot keys for key scan

command

■ Low power consumption in standby mode

■ 2 general purpose input ports (SW1, SW2)

■ Available in PQFP-52 package

) to –30V (VSS)

DD

- 33.3V max)

, and D

IN

OUT

)

STFPC311

Front panel controller/driver

with standby power management

PQFP-52

Description

The STFPC311 is a complete, low-cost, integrated solution for controlling and driving a front panel Vacuum Fluorescent Display (VFD). It is ideal for decreasing power consumption in standby mode by reducing the application standby current to a minimum. It also contains a built-in remote control decoder module.

While in the standby mode of operation, a valid key press or signal from infrared decoder will start a proper power-up see Figure 6 on page 12.

The STFPC311 integrates a VFD controller with a driver that is run on a 1/8 to 1/16-duty factor. It consists of 12 segments output lines, 8 grid output lines, 8 shared segments/grid output drive lines, a display memory, a control circuit, and a key scan circuit. Serial data is input to the STFPC311 through the SPI Interface of a microcontroller (STB, D

Additionally, this IC can support 2 general purpose input switches (SW1 and SW2).

Features

, D

IN

, and CLK).

OUT

■ DVD players

■ VCD players

■ AV equipment like Home Stereo

■ POS Systems

Order Codes

Part number Temperature range Package

STFPC311 -40 to 85°C PQFP-52

May 2006 Rev 1 1/39

www.st.com

39

STFPC311

Contents

1 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.1 Normal mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.2 Receive operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.3 Transmit operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4 Standby or power-down mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.5 IR Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.6 Watchdog timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.6.1 Watchdog timer operation during power-up . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.6.2 Watchdog timer operation during power-down . . . . . . . . . . . . . . . . . . . . . . . 10

3.6.3 Watchdog timer operation during standby . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.7 Flow charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

4 Display RAM address and display mode . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5.1 LED Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5.2 SW Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

6 Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6.1 Configuration mode setting command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6.2 Data setting command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.3 Address setting command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.4 Display control and hotkey setting command . . . . . . . . . . . . . . . . . . . . . . . . 20

7 Programmable hotkeys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

7.1 IR Remote control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

7.2 Front panel keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2/39

STFPC311

8 Default status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

8.1 Power-up default status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

8.2 STANDBY status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

9 Remote control protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

9.1 RC-5 remote control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

9.2 SPI interface IR data transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

9.3 NEC remote control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

10 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

10.1 Power consumption estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

11 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

12 Timing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

13 Serial communication format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

14 Typical application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

15 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

16 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

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1 Functional description STFPC311

1 Functional description

The STFPC311 receives serial data from the microcontroller through the SPI interface, latches the data, and then masks the inputs from the MCU. This data consists of commands followed by data. There are 4 types of commands:

● configuration,

● data,

● address, and

● display.

The STFPC311 integrates the supply standby power management functionality, remote control decoder, and a 28-bit VFD driver. Microcontrollers usually run the first two tasks.

This device reduces the stand-by power consumption of the whole Front Panel application as well as the hardware by integrating the infrared (IR) remote control decoder.

A dedicated supply voltage powers the STFPC311 directly from the main supply board. When power is plugged in, control of the power supply management is done using the following pins:

1. STBY,

2. IR_DATA_IN, and

3. READY.

1.1 Block diagram

Figure 1. Block diagram

IR_ DATA_ IN

READY/STBY_n

D

IN

D

OUT

CLK

CLK STB

STB

V

DD

R

OSC

SW1

SW2

KEY1

KEY1 KEY2

KEY2

2

Seri al

OSC

2-bit

Lat ch

SPI

I/F

Remote Control

Decoder & Stand

By Function

Command Decod er

Display Memory

(20 x 16)

Timing Generator

Key Scan and

Dimmi ng Circuit

Key Dat a Memor y

(2 x 12)

2

Lat ch

4-bit

LED1

LED2

LED3

LED4

STBY

MUTE

20-bit

Out put

Lat ch

16-bit

Shift

Regis ter

V

DD

(+3.3V)

GND

(0V)

Watchdog

Timer

20 12

8

Dat a

Selec tor

8

16

V

SS

(-30V)

SEG1/KS1

Dri vers

Segment

8

Multiplexed

Gri d

8

Dri vers

SEG12/KS2

SEG13/GRID16

SEG20/GRID9

GRID8

GRID1

4/39

STFPC311 2 Pin connection

2 Pin connection

Figure 2. Connection diagram (top view PQFP-52)

STFPC311

Note: For a description of the behavior of each pin, refer to the Table 1: Pin description on page 6.

5/39

2 Pin connection STFPC311

2.1 Pin description

Table 1. Pin description

Pin Nº Symbol Type Name and function

1 OSC I This is the oscillator input pin. Connect this pin to an external resistor.

2, 3 SW1, SW2 I General purpose switch input ports.

4MUTEO

5S TBY O

7 GND POWER Connect this pin to system GND.

High level indicates mute status for audio. Low level indicates normal working.Note 1

there is a typo. Pin5 and name is STBY. Standby output to put the MCU in low power mode.

It is a command to the main power board. High level indicates stand-by status. Low level indicates normal working. Note 1

8, 9 KEY1, KEY2 I

Input data to these pins from external keyboard are latched at end of the display cycle (maximum keyboard size is 12 x 2).

High level on this pin means that main board chip has been working

10 READY I

normally.Note 1 This pin should never float. It is recommended have a pull-down resistor on this input.

1 IR_DATA_IN I Remote control input. Feeds the IR data from photodiode to this pin.

14 to 25

12, 26

27 to 34

SEG1/KS1 to SEG12/KS12

V

SS

SEG13/GRID16

to SEG20/GRID9

O Segment output pins (dual function as key source).

V

POWER

outputs high voltage pull-down level. VDD--33.3V max.

FD

O These pins are selectable for segment or grid driving.

35 to 37 GRID8 to GRID6 O Grid output pins.

6, 13,38

V

DD

POWER 3.3V ± 0.3V Core main supply voltage.

39 NC O Not used. Left unconnected.

40 to 44 GRID5 to GRID1 O Grid output pins.

Initializes the serial interface at the rising or falling edge to make the STFPC31 wait for reception of command. The data input after the falling

45 STB I

edge of STB is processed as a command. While the command data is processed, current processing is stopped, and the serial interface is initialized. While STB is high, CLK is ignored and any instruction from

the MCU is neglected.

46 CLK I

Reads serial data at the rising edge, and outputs data at the falling edge.

47

48

49-52

D

IN

D

OUT

LED1, LED2,

LED3, LED4

O

O CMOS outputs (20mA, max).

Inputs serial data at the rising edge of the shift clock, starting from the

I

lower bit.

Outputs serial data at the faling edge of the shift clock, starting from the lower bit. This is the N-channel opendrain output pin.

Note: 1 For a detailed behavioral description of these pins, refer to the “STFPC311 Timing Power

Stand-by Sequencer Flow-Chart”. See Table 6 on page 12

6/39

STFPC311 3 Initialization

3 Initialization

After the power is plugged in, the device will supply power to all of the components (including the host processor) by setting STBY to logic low in order to allow the host processor to program the STFPC311. Once the STBY is set to low, the watchdog timer starts to count up to 10s (10s is the default value of the watchdog timer upon power-up). When the READY is asserted within this time, it indicates that the system has booted up well. If the READY pin is not asserted (logic high) within this time (10s), the STFPC311 will put the system into standby mode again by setting STBY to logic high.

If READY is detected as logic high, the watchdog timer will be turned OFF. The main processor should program the remote control hot key and initialize the other parameters of the STFPC311 in preparation for normal operation before the system goes into standby mode. After all of the STFPC311 configuration is finished, the host processor may set the READY to low so that the STFPC311 enters standby mode. The STFPC311 then sets the MUTE pin to logic high to mute the audio output as well as the STBY pin to logic high. As a consequence of this action, the main supply voltage is turned off.

3.1 Normal mode of operation

After the power is plugged in, the device will supply power to all of the components (including the host processor) by setting STBY to logic low in order to allow the host processor to program the STFPC311. Once the STBY is set to low, the watchdog timer starts to count up to 10s (10s is the default value of the watchdog timer upon power-up). When the READY is asserted within this time, it indicates that the system has booted up well. If the READY pin is not asserted (logic high) within this time (10s), the STFPC311 will put the system into standby mode again by setting STBY to logic high.

If READY is detected as logic high, the watchdog timer will be turned OFF. The main processor should program the remote control hot key and initialize the other parameters of the STFPC311 in preparation for normal operation before the system goes into standby mode. After all of the STFPC311 configuration is finished, the host processor may set the READY to low so that the STFPC311 enters standby mode. The STFPC311 then sets the MUTE pin to logic high to mute the audio output as well as the STBY pin to logic high. As a consequence of this action, the main supply voltage is turned off.

3.2 Receive operation

In receive condition, the STFPC311 waits for a valid command from the MCU. The receive circuit of STFPC311 receives 8 bit serial data, latches the data and then masks the inputs from the MCU. Refer to Figure 28 on page 32 for receive timing.

3.3 Transmit operation

In transmit condition, the STFPC311 sends the 8-bit serial data (LSB transmitted first) whenever a key is pressed or IR data is received. STFPC311 transmits data on the falling edge of CLK. Refer to Figure 29 on page 32 for transmit timing.

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3 Initialization STFPC311

3.4 Standby or power-down mode

Once the STFPC311 detects the status change of the READY to a logic low or after the preset waiting time (1s to 15s) has elapsed, the STFPC311 sets the STBY pin to a logic high to turn off the power. The MUTE signal is set to high before the power is turned off. The STFPC311 always senses the level on the READY pin during normal operation.

3.5 IR Decoding

Encoded IR data from photodiode is supplied to the IR_DATA_IN input pin. The data is decoded by the internal remote control decoder module of STFPC311. In standby mode, the remote control decoder recognizes a set of predefined commands (such as STANDBY, PLAY, and OPEN/CLOSE), and takes appropriate action to manage the power supply.

These predefined commands are known as "hot keys" and are programmable. The decoded IR commands are passed on to the main processor through the SPI interface by sending 3 bytes of data on the D

OUT

pin.

3.6 Watchdog timer

The watchdog timer is used to detect an out-of-control microprocessor. The watch dog timer is implemented in the STFPC311 to detect the abnormal processor behavior or processor-hung condition. The default state of the watchdog timer is 10s when the device powers-up. It is initialized by writing to the watchdog register and can be programmed to up to 15s (4-bit watchdog timer, present in the configuration mode setting command).

If the processor does not reset the timer within the specified period, the STFPC311 will put the entire system into standby mode to reset the appliance that has stopped abnormally. The action to take when the watchdog timer has reached its count is to set the Watchdog Action register. The watchdog timer can be reset by the host processor by sending a command to reset the watchdog timer. The time-out period then starts over again. If the processor needs to be reset as a result of a hung condition (signalled using the STBY output of the STFPC311), the watchdog timer uses the amount of the time-out programmed into the Watchdog Register by the user to generate an interrupt.

Note: The accuracy of the timer is within ±10% the selected resolution. This depends on the value of

the external bias resistor, as it determines the internal clock frequency.

The watchdog function is automatically set to 10s upon power-up and the Watchdog Interrupt is cleared. This boot-up watchdog timer is used to make sure that if the host processor hangs during the first boot-up, the STFPC311 will put the system to standby mode. During the first boot-up, the watchdog timer is disabled after the first READY signal is received.

8/39

STFPC311 3 Initialization

3.6.1 Watchdog timer operation during power-up

Figure 3. Power-up condition

Note: Watchdog timer is turned off by default upon READY assertion.

If Watchdog is to be kept on during READY high condition, the WDG registers must be set accordingly by proper commands through SPI bus.

In this power-up condition, the watchdog timer is triggered by internal POR pulse.

During power-up, the watchdog timer value is 10s.

9/39

3 Initialization STFPC311

3.6.2 Watchdog timer operation during power-down

Figure 4. Power-down condition

Note: The watchdog timer can be kept on during normal conditions when READY is high (depending

on the user’s settings).

In this condition, the watchdog timer can be disabled or enabled. If the watchdog timer is enabled, the timer needs to be cleared before the programmed count of the timer is reached. If the programmed count is reached, the STBY will be asserted.

Caution: It is advisable not to enable the watchdog timer during normal operation.

10/39

STFPC311 3 Initialization

3.6.3 Watchdog timer operation during standby

● When a hot-key signal is detected either from the front panel or remote control during

standby, the STBY de-asserts.

● The de-assertion of the STBY triggers the watchdog timer.

● The timer value is the programmed value that is set by the user (1s-15s). If the user did not

change the value before entering standby, then it remains 10s.

● Also note: that The watchdog timer is off when the STFPC311 is in the standby mode to

save power.

Figure 5. Standby condition

3a) Standby Condition (Normal behavior)

Hot key com mand from IR

or Key pad for wake up

STBY

W DG timer triggers

READY

MUTE

3b) Standby Condition (Abnormal behavior, processor is not responding)

Hot key com mand from IR

or Key pad for wake up

STBY

READY

MUTE

READY asserts within programm ed timer value (1 s-15s)

Signals STBY after

WDG timer

triggers

Signals STBY after W DG count is over

W DG count is over

REA DY continues to remain low

The watchdog timer is triggered by a de-assertion of the STBY signal or by the internal Power-on Reset signal. It is not affected by the STB pin.

11/39

3 Initialization STFPC311

3.7 Flow charts

Figure 6. Timing power standby sequencer flow chart

* Programmable from 1 to 15s.

† FPK = Front Panel Keys

12/39