Philips pcf8584 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

PCF8584

C-bus controller

Product speciﬁcation Supersedes data of May 1994 File under Integrated Circuits, IC12

1995 Aug 29

Philips Semiconductors Product speciﬁcation

I2C-bus controller

CONTENTS

1 FEATURES 2 GENERAL DESCRIPTION 3 ORDERING INFORMATION 4 BLOCK DIAGRAM 5 PINNING 6 FUNCTIONAL DESCRIPTION

6.1 General

6.2 Interface Mode Control (IMC)

6.3 Set-up registers S0', S2 and S3

6.4 Own address register S0'

6.5 Clock register S2

6.6 Interrupt vector S3

6.7 Data shift register/read buffer S0

6.8 Control/status register S1

6.8.1 Register S1 control section

6.8.1.1 PIN (Pending Interrupt Not)

6.8.1.2 ESO (Enable Serial Output)

6.8.1.3 ES1 and ES2

6.8.1.4 ENI

6.8.1.5 STA and STO

6.8.1.6 ACK

6.8.2 Register S1 status section

6.8.2.1 PIN bit

6.8.2.2 STS

6.8.2.3 BER

6.8.2.4 LRB/AD0

6.8.2.5 AAS

6.8.2.6 LAB

6.8.2.7 BB

6.9 Multi-master operation

6.10 Reset

6.11 Comparison to the MAB8400 I2C-bus interface

6.11.1 Deleted functions

6.11.2 added functions

6.12 Special function modes

6.12.1 Strobe

6.12.2 Long-distance mode

6.12.3 Monitor mode 7 SOFTWARE FLOWCHART EXAMPLES

7.1 Initialization

7.2 Implementation 8I 9 LIMITING VALUES 10 HANDLING 11 DC CHARACTERISTICS

C-BUS TIMING DIAGRAMS

PCF8584

12 I2C-BUS TIMING SPECIFICATIONS 13 PARALLEL INTERFACE TIMING 14 APPLICATION INFORMATION 15 PACKAGE OUTLINES 16 SOLDERING

16.1 Introduction

16.2 DIP

16.2.1 Soldering by dipping or by wave

16.2.2 Repairing soldered joints

16.3 SO

16.3.1 Reflow soldering

16.3.2 Wave soldering

16.3.3 Repairing soldered joints 17 DEFINITIONS 18 LIFE SUPPORT APPLICATIONS 19 PURCHASE OF PHILIPS I2C COMPONENTS

1995 Aug 29 2

Philips Semiconductors Product speciﬁcation

I2C-bus controller

1 FEATURES

• Parallel-bus to I2C-bus protocol converter and interface

• Compatible with most parallel-bus

microcontrollers/microprocessors including 8049, 8051, 6800, 68000, and Z80

• Both master and slave functions

• Automatic detection and adaption to bus interface type

• Programmable interrupt vector

• Multi-master capability

• I2C-bus monitor mode

• Long-distance mode (4-wire)

• Operating supply voltage 4.5 to 5.5 V

• Operating temperature range: −40 to +85 °C.

3 ORDERING INFORMATION

TYPE NUMBER

NAME DESCRIPTION VERSION

PCF8584P DIP20 plastic dual in-line package; 20 leads (300 mil) SOT146-1 PCF8584T SO20 plastic small outline package; 20 leads; body width 7.5 mm SOT163-1

2 GENERAL DESCRIPTION

The PCF8584 is an integrated circuit designed in CMOS technology which serves as an interface between most standard parallel-bus microcontrollers/microprocessors and the serial I2C-bus. The PCF8584 provides both master and slave functions.

Communication with the I2C-bus is carried out on a byte-wise basis using interrupt or polled handshake. It controls all the I2C-bus specific sequences, protocol, arbitration and timing. The PCF8584 allows parallel-bus systems to communicate bidirectionally with the I

PACKAGE

PCF8584

C-bus.

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Philips Semiconductors Product speciﬁcation

I2C-bus controller

4 BLOCK DIAGRAM

handbook, full pagewidth

SDA/

SDA OUT

(3)

DIGITAL

FILTER

DATA CONTROL

PARALLEL BUS

DB6DB7 DB5 DB4 DB3 DB2 DB1 DB0 1415 13 12 11 9 8 7

MSB

DATA SHIFT REGISTER S0 AND READ BUFFER

MSB LSB

(1)

READ BUFFER

SHIFT REGISTER

COMPARATOR S0, S0'

OWN ADDRESS S0'

PCF8584

DD SS

20 10

read only

write

only

(1)

SCL/

SCL IN

PCF8584

INTERRUPT VECTOR S3

(3)

DIGITAL

FILTER

SCL CONTROL

CLOCK PRESCALER SCL MULTIPLEXER BUS BUSY LOGIC ARBITRATION LOGIC

19 17 6 RESET/ CS A0

STROBE (O.C.)

CLOCK REGISTER S2

CONTROL STATUS

CONTROL STATUS REGISTER S1

PARALLEL BUS CONTROL

WR (R/W)18RD (DTACK)

CLOCK REGISTER S2

AD0/

BERSTS0PIN

LRB

(2) (2)

default: 00H 80XX 0FH 68XXX

S20S21S22S23S24000

ACKSTOSTAENIES2ES1ES0PIN

BBLABAAS

541 INT

SCL OUT

write only

read only

IACK

(3) (3)

SDA IN

CLK

MBD908 - 1

(1) X = don’t care. (2) Pin mnemonics between brackets indicate the 68000 mode pin designations. (3) These pin mnemonics represent the long-distance mode pin designations.

1995 Aug 29 4

Fig.1 Block diagram.

Philips Semiconductors Product speciﬁcation

I2C-bus controller

5 PINNING

SYMBOL PIN I/O DESCRIPTION

CLK 1 I clock input from microcontroller clock generator (internal pull-up)

SDA or SDA OUT

SCL or SCL IN

IACK or SDA IN

INT or SCL OUT

A0 6 I Register select input (internal pull-up); this input selects between the control/status

DB0 7 I/O bidirectional 8-bit bus Port 0 DB1 8 I/O bidirectional 8-bit bus Port 1 DB2 9 I/O bidirectional 8-bit bus Port 2 V

DB3 11 I/O bidirectional 8-bit bus Port 3 DB4 12 I/O bidirectional 8-bit bus Port 4 DB5 13 I/O bidirectional 8-bit bus Port 5 DB6 14 I/O bidirectional 8-bit bus Port 6 DB7 15 I/O bidirectional 8-bit bus Port 7 RD

(DTACK) CS 17 I chip select input (internal pull-up) WR (R/W) 18 I WR is the write control input for MAB8048, MAB8051, or Z80-types

RESET/ STROBE

2 I/O I

3 I/O I

4 I Interrupt acknowledge input (internal pull-up); when this signal is asserted the

5 O Interrupt output (open-drain); this signal is enabled by the ENI ﬂag in register S1.

10 − ground

16 I/(O) RD is the read control input for MAB8049, MAB8051 or Z80-types. DTACK is the

19 I/O Reset input (open-drain); this input forces the I2C-bus controller into a predeﬁned

20 − supply voltage

C-bus serial data input/output (open-drain). Serial data output in

long-distance mode.

C-serial clock input/output (open-drain). Serial clock input in long-distance mode.

interrupt vector in register S3 will be available at the bus Port if the ENI ﬂag is set. Serial data input in long-distance mode.

It is asserted when the PIN ﬂag is reset. (PIN is reset after 1 byte is transmitted or received over the I2C-bus). Serial clock output in long-distance mode.

register and the other registers. Logic 1 selects register S1, logic 0 selects one of the other registers depending on bits loaded in ESO, ES1, and ES2 of register S1.

data transfer control output for 68000-types (open-drain).

(internal pull-up). R/W control input for 68000-types.

state; all ﬂags are reset, except PIN, which is set. Also functions as strobe output.

PCF8584

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Philips Semiconductors Product speciﬁcation

I2C-bus controller

handbook, halfpage

SDA or SDA OUT

SCL or SCL IN

IACK or SDA IN

INT or SCL OUT

(1) Pin mnemonics between brackets indicate the 68000 mode

pin designations.

CLK

DB0 DB1

DB2

1 2 3 4 5

PCF8584

6 7 8 9

MLA012 - 1

Fig.2 Pin configuration.

RESET / STROBE

19 18

WR (R/W) CS

17 16

RD (DTACK)

DB7 DB6

DB5

13 12

DB4 DB3

PCF8584

Table 1 Control signals utilized by the PCF8584 for

microcontroller/microprocessor interfacing

TYPE R/

8048/ 8051

68000 yes no no yes yes

(1)

Z80 no yes yes no yes

The structure of the PCF8584 is similar to that of the

C-bus interface section of the

I MABXXXX/PCF84(C)XX-series of microcontrollers, but with a modified control structure. The PCF8584 has five internal register locations. Three of these (own address register S0', clock register S2 and interrupt vector S3) are used for initialization of the PCF8584. Normally they are only written once directly after resetting of the PCF8584.

The remaining two registers function as double registers (data buffer/shift register S0, and control/status register S1) which are used during actual data transmission/reception. By using these double registers, which are separately write and read accessible, overhead for register access is reduced. Register S0 is a combination of a shift register and data buffer.

W WR R DTACK IACK

no yes yes no no

6 FUNCTIONAL DESCRIPTION

6.1 General

The PCF8584 acts as an interface device between standard high-speed parallel buses and the serial I

C-bus. On the I2C-bus, it can act either as master or slave. Bidirectional data transfer between the I2C-bus and the parallel-bus microcontroller is carried out on a byte-wise basis, using either an interrupt or polled handshake. Interface to either 80XX-type (e.g. MAB8048, MAB8051, Z80) or 68000-type buses is possible. Selection of bus type is automatically performed (see Section 6.2).

6.2 Interface Mode Control (IMC)

Selection of either an 80XX mode or 68000 mode interface is achieved by detection of the first

WR-CS signal sequence. The concept takes advantage of the fact that the write control input is common for both types of interfaces. An 80XX-type interface is default. If a HIGH-to-LOW transition ofWR (R/W) is detected while CS is HIGH, the 68000-type interface mode is selected and theDTACK output is enabled. Care must be taken thatWR and CS are stable after reset.

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Philips Semiconductors Product speciﬁcation

I2C-bus controller

handbook, full pagewidth

FILTER

t = 16CLK

RESET

STROBE

CS A0

PCF8584

I2C-bus

SCL

ENRD

WR/

RD/

R/W

DTACK

INT IACK CLK

SIO DIVIDER

(S21 and S20)

(50 : 50)

(1.5 MHz)

DIVIDER

(S24, S23, S22)

/2, 3, 4, 5, 8

MBE706

handbook, full pagewidth

R/W

DTACK

(1) Bus timing; 68000 mode write cycle. (2) Bus timing; 80XX mode.

mode locked

mode select

(1)

mode select

(2)

MBE707

Fig.3 68000/80XX timing sequence utilized by the Interface Mode Control (IMC).

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Philips Semiconductors Product speciﬁcation

I2C-bus controller

6.3 Set-up registers S0', S2 and S3

Registers S0', S2 and S3 are used for initialization of the PCF8584 (see Fig.5 ‘Initialization sequence’ flowchart).

6.4 Own address register S0'

When the PCF8584 is addressed as slave, this register must be loaded with the 7-bit I PCF8584 is to respond. During initialization, the own address register S0' must be written to, regardless whether it is later used. The Addressed As Slave (AAS) bit in status register S1 is set when this address is received (the value in S0 is compared with the value in S0'). Note that the S0 and S0' registers are offset by one bit; hence, programming the own address register S0' with a value of 55H will result in the value AAH being recognized as the PCF8584’s slave address (see Fig.1).

Programming of S0' is accomplished via the parallel-bus when A0 is LOW, with the appropriate bit combinations set in control status register S1 (S1 is written when pin A0 = HIGH). Bit combinations for accessing all registers are given in Table 5. After reset, S0' has default address 00H (PCF8584 is thus initially in monitor mode, see Section 6.12).

C-bus address to which the

PCF8584

I2C-bus signals SCL and SDA. Selection for adaption to external clock rates is shown in Table 3.

Programming of S2 is accomplished via the parallel-bus when A0 = LOW, with the appropriate bit combinations set in control status register S1 (S1 is written when A0 = HIGH). Bit combinations for accessing all registers are given in Table 5.

Table 3 Register S2 selection of clock frequency

INTERNAL CLOCK FREQUENCY

S24 S23 S22

(1)

X 1 0 0 4.43 1016 1108 11112

Note

1. X = don’t care.

6.6 Interrupt vector S3

clk

(MHz)

6.5 Clock register S2

of 4 different I

C-bus SCL frequencies which are shown in Table 2. Note that these SCL frequencies are only obtained when bits S24, S23 and S22 are programmed to the correct input clock frequency (f

clk

Table 2 Register S2 selection of SCL frequency

BIT APPROXIMATE SCL

S21 S20

FREQUENCY f

(kHz)

SCL

00 90 01 45 10 11 1 1 1.5

S22, S23 and S24 are used for control of the internal clock prescaler. Due to the possibility of varying microcontroller clock signals, the prescaler can be programmed to adapt to 5 different clock rates, thus providing a constant internal clock. This is required to provide a stable time base for the SCL generator and the digital filters associated with the

The interrupt vector register provides an 8-bit user-programmable vector for vectored-interrupt microcontrollers. The vector is sent to the bus port (DB7 to DB0) when an interrupt acknowledge signal is asserted and the ENI (enable interrupt) flag is set. Default vector values are:

• Vector is ‘00H’ in 80XX mode

• Vector is ‘0FH’ in 68000 mode.

On reset the PCF8584 is in the 80XX mode, thus the default interrupt vector is ‘00H’.

6.7 Data shift register/read buffer S0

C-bus. All read and write operations to/from the I2C-bus are done via this register. S0 is a combination of a shift register and a data buffer; parallel data is always written to the shift register, and read from the data buffer. I2C-bus data is always shifted in or out of shift register S0.

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Philips Semiconductors Product speciﬁcation

I2C-bus controller

andbook, full pagewidth

to/from

C-Bus SDA line

to/from microcontroller parallel bus

DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

Read Buffer

Data Shift Register S0 and Read Buffer

Shift register

Read

only

Write

only

MBE705

PCF8584

Fig.4 Data shift register/bus buffer S0.

In receiver mode the data from the shift register is copied to the read buffer during the acknowledge phase. Further reception of data is inhibited (SCL held LOW) until the S0 read buffer is read (see Section 6.8.1.1).

In the transmitter mode data is transmitted to the I2C-bus as soon as it is written to the S0 shift register if the serial I/O is enabled (ESO = 1).

Remarks:

1. A minimum of 6 clock cycles must elapse between consecutive parallel-bus accesses to the PCF8584 when the I2C-bus controller operates at 8 or 12 MHz. This may be reduced to 3 clock cycles for lower operating frequencies.

2. To start a read operation immediately after a write, it is necessary to read the S0 read buffer in order to invoke reception of the first byte (‘dummy read’ of the address). Immediately after the acknowledgement, this first byte will be transferred from the shift register to the read buffer. The next read will then transfer the correct value of the first byte to the microcontroller bus (see Fig.7).

6.8 Control/status register S1

C-bus operation and provides I2C-bus status information. Register S1 is accessed by a HIGH signal on register select input A0. For more efficient communication between microcontroller/processor and the I2C-bus, register S1 has separate read and write functions for all bit positions (see Fig.3). The write-only section provides register access control and control over I2C-bus signals, while the read-only section provides I2C-bus status information.

Table 4 Control/status register S1

CONTROL/STATUS BITS MODE

Control

(1)

PIN ESO ES1 ES2 ENI STA STO ACK write

only

Status

(2)

PIN 0

(3)

STS BER AD0/

LRB

AAS LAB BB read

only

Notes

1. For further information see Section 6.8.1.

2. For further information see Section 6.8.2.

3. Logic 1 if not-initialized.

1995 Aug 29 9

Philips Semiconductors Product speciﬁcation

I2C-bus controller

6.8.1 REGISTER S1 CONTROL SECTION The write-only section of S1 enables access to registers S0, S0', S1, S2 and S3, and controls I2C-bus operation;

see Table 4.

PCF8584

6.8.1.1 PIN (Pending Interrupt Not)

When the PIN bit is written with a logic 1, all status bits are reset to logic 0. This may serve as a software reset function (see Figs 5 to 9). PIN is the only bit in S1 which may be both read and written to. PIN is mostly used as a status bit for synchronizing serial communication, see Section 6.8.2.

6.8.1.2 ESO (Enable Serial Output)

ESO enables or disables the serial I2C-bus I/O. When ESO is LOW, register access for initialization is possible. When ESO is HIGH, I2C-bus communication is enabled; communication with serial shift register S0 is enabled and the S1 bus status bits are made available for reading.

Table 5 Register access control; ESO = 0 (serial interface off) and ESO = 1 (serial interface on)

INTERNAL REGISTER ADDRESSING 2-WIRE MODE

A0 ES1 ES2

ESO = 0; serial interface off

10X1 0001 0011 0101

(1)

IACK FUNCTION

(2) (2) (2) (2)

R/W S1: control R/W S0': (own address) R/W S3: (interrupt vector) R/W S2: (clock register)

ESO = 0; serial interface on

1 0 X 1 W S1: control 1 0 X 1 R S1; status 0 0 0 1 R/W S0: (data) 0 0 1 1 R/W S3: (interrupt vector)

X 0 X 0 R S3: (interrupt vector ACK cycle))

Notes

1. With ESO = 0, bits ENI, STA, STO and ACK of S1 can be read for test purposes.

2. ‘X’ if ENI = 0.

6.8.1.3 ES1 and ES2

ES1 and ES2 control selection of other registers for initialization and control of normal operation. After these bits are programmed for access to the desired register (shown in Table 5), the register is selected by a logic LOW level on register select pin A0.

6.8.1.4 ENI

This bit enables the external interrupt output INT, which is generated when the PIN bit is active (logic 0).

This bit must be set to logic 0 before entering the long-distance mode, and remain at logic 0 during operation in long-distance mode.

1995 Aug 29 10

Philips Semiconductors Product speciﬁcation

I2C-bus controller

PCF8584

6.8.1.5 STA and STO

These bits control the generation of the I2C-bus START condition and transmission of slave address and R/W bit, generation of repeated START condition, and generation of the STOP condition (see Table 7).

Table 6 Register access control; ESO = 1 (serial interface on) and ES1 = 1; long-distance (4-wire) mode; note 1

INTERNAL REGISTER ADDRESSING: LONG-DISTANCE (4-WIRE) MODE

A0 ES1 ES2

1 1 X 1 W S1: control 1 1 X X R S1; status 0 1 X X R/W S0; (data)

Note

1. Trying to read from or write to registers other than S0 and S1 (setting ESO = 0) brings the PCF8584 out of the

long-distance mode.

Table 7 Instruction table for serial bus control

STA STO PRESENT MODE FUNCTION OPERATION

1 0 SLV/REC START transmit START + address, remain

1 0 MST/TRM REPEAT START same as for SLV/REC 0 1 MST/REC;

MST/TRM

1 1 MST DATA CHAINING send STOP, START and address after

0 0 ANY NOP no operation; note 3

IACK FUNCTION

MST/TRM if R/ go to MST/REC if R/W=1

STOP READ; STOP WRITE

transmit STOP go to SLV/REC mode; note 1

last master frame without STOP sent; note 2

W=0;

Notes

1. In master receiver mode, the last byte must be terminated with ACK bit HIGH (‘negative acknowledge’).

2. If both STA and STO are set HIGH simultaneously in master mode, a STOP condition followed by a START

condition + address will be generated. This allows ‘chaining’ of transmissions without relinquishing bus control.

3. All other STA and STO mode combinations not mentioned in Table 7 are NOPs.

6.8.1.6 ACK

This bit must be set normally to a logic 1. This causes the I2C-bus controller to send an acknowledge automatically after each byte (this occurs during the 9th clock pulse). The bit must be reset (to logic 0) when the I2C-bus controller is operating in master/receiver mode and requires no further data to be sent from the slave transmitter. This causes a negative acknowledge on the I2C-bus, which halts further transmission from the slave device.

6.8.2 R The read-only section of S1 enables access to I2C-bus status information; see Table 4.

1995 Aug 29 11

EGISTER S1 STATUS SECTION

Philips Semiconductors Product speciﬁcation

I2C-bus controller

6.8.2.1 PIN bit

‘Pending Interrupt Not’ (MSB of register S1) is a status flag which is used to synchronize serial communication and is set to logic 0 whenever the PCF8584 requires servicing. The PIN bit is normally read in polled applications to determine when an I2C-bus byte transmission/reception is completed. The PIN bit may also be written, see Section 6.8.1.

Each time a serial data transmission is initiated (by setting the STA bit in the same register), the PIN bit will be set to logic 1 automatically (inactive). When acting as transmitter, PIN is also set to logic 1 (inactive) each time S0 is written. In receiver mode, the PIN bit is automatically set to logic 1 (inactive) each time the data register S0 is read.

After transmission or reception of one byte on the I (9 clock pulses, including acknowledge), the PIN bit will be automatically reset to logic 0 (active) indicating a complete byte transmission/reception. When the PIN bit is subsequently set to logic 1 (inactive), all status bits will be reset to logic 0. PIN is also set to zero on a BER (bus error) condition.

In polled applications, the PIN bit is tested to determine when a serial transmission/reception has been completed. When the ENI bit (bit 4 of write-only section of register S1) is also set to logic 1 the hardware interrupt is enabled. In this case, the PIN flag also triggers an external interrupt (active LOW) via the INT output each time PIN is reset to logic 0 (active).

When acting as slave transmitter or slave receiver, while PIN = 0, the PCF8584 will suspend I2C-bus transmission by holding the SCL line LOW until the PIN bit is set to logic 1 (inactive). This prevents further data from being transmitted or received until the current data byte in S0 has been read (when acting as slave receiver) or the next data byte is written to S0 (when acting as slave transmitter).

PIN bit summary:

• The PIN bit can be used in polled applications to test

when a serial transmission has been completed. When the ENI bit is also set, the PIN flag sets the external interrupt via the INT output.

• Setting the STA bit (start bit) will set PIN = 1 (inactive).

• In transmitter mode, after successful transmission of

one byte on the I2C-bus the PIN bit will be automatically reset to logic 0 (active) indicating a complete byte transmission.

• In transmitter mode, PIN is set to logic 1 (inactive) each

time register S0 is written.

C-bus

PCF8584

• In receiver mode, PIN is set to logic 0 (active) on completion of each received byte. Subsequently, the SCL line will be held LOW until PIN is set to logic 1.

• In receiver mode, when register S0 is read, PIN is set to logic 1 (inactive).

• In slave receiver mode, an I set PIN = 0 (active).

• PIN = 0 if a bus error (BER) occurs.

6.8.2.2 STS

When in slave receiver mode, this flag is asserted when an externally generated STOP condition is detected (used only in slave receiver mode).

6.8.2.3 BER

Bus error; a misplaced START or STOP condition has been detected. Resets BB (to logic 1; inactive), sets PIN = 0 (active).

6.8.2.4 LRB/AD0

‘Last Received Bit’ or ‘Address 0 (General Call) bit’. This status bit serves a dual function, and is valid only while PIN = 0:

1. LRB holds the value of the last received bit over the

I2C-bus while AAS = 0 (not addressed as slave). Normally this will be the value of the slave acknowledgement; thus checking for slave acknowledgement is done via testing of the LRB.

2. AD0; when AAS = 1 (‘Addressed As Slave’ condition),

the I2C-bus controller has been addressed as a slave. Under this condition, this bit becomes the ‘AD0’ bit and will be set to logic 1 if the slave address received was the ‘general call’ (00H) address, or logic 0 if it was the I2C-bus controller’s own slave address.

6.8.2.5 AAS

‘Addressed As Slave’ bit. Valid only when PIN = 0. When acting as slave receiver, this flag is set when an incoming address over the I2C-bus matches the value in own address register S0' (shifted by one bit, see Section 6.4), or if the I2C-bus ‘General Call’ address (00H) has been received (‘General Call’ is indicated when AD0 status bit is also set to logic 1, see Section 6.8.2.4).

6.8.2.6 LAB

‘Lost Arbitration’ Bit. This bit is set when, in multi-master operation, arbitration is lost to another master on the I2C-bus.

C-bus STOP condition will

1995 Aug 29 12

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Philips pcf8584 DATASHEETS

Specifications and Main Features

Frequently Asked Questions

User Manual