ST72344S2 datasheet(168/247 Pages) STMICROELECTRONICS

168 / 247 page

On-chip peripherals

ST72344xx, ST2345xx

168/247

Doc ID 12321 Rev 6

Figure 71.

I2C3S interface block diagram

11.7.3

General description

In addition to receiving and transmitting data, I2C3S converts it from serial to parallel format

and vice versa. The interrupts are enabled or disabled by software. The I2C3S is connected

to the I2C bus by a data pin (SDA) and by a clock pin (SCL). It can be connected both with a

standard I2C bus and a Fast I2C bus. The interface operates only in Slave mode as

transmitter/receiver.

In order to fully emulate standard I2C EEPROM devices with highest transfer speed, the

peripheral prevents I2C clock signal stretching and performs data transfer between the shift

Communication flow

A serial data transfer normally begins with a start condition and ends with a stop condition.

Both start and stop conditions are generated by an external master. Refer to Figure 67 for

the standard protocol. The I2C3S is not a master and is not capable of generating a

start/stop condition on the SDA line. The I2C3S is capable of recognizing 3 slave addresses

which are user programmable. The three I2C slave addresses can be individually

enabled/disabled by software.

Since the I2C3S interface always acts as a slave, it does not generate a clock. Data and

addresses are transferred as 8-bit bytes, MSB first. The first byte following the start

condition contains the slave address. A 9th clock pulse follows the 8 clock cycles of a byte

transfer, during which the receiver must send an acknowledge bit to the transmitter.

I2C SLAVE ADDRESS 1

I2C SLAVE ADDRESS 2

I2C SLAVE ADDRESS 3

CPU

RAM

128 BYTES

SLAVE 3 BUFFER

256 BYTES

SLAVE 1 BUFFER

256 BYTES

SLAVE 2 BUFFER

DMA

COMPARATOR

CONTROL LOGIC

8-BIT

SHIFT REGISTER

SCL or SCLI

SDA or SDAI

Slave 1 or 2 Interrupt

Slave 3 Interrupt

DATA E2PROM

256 BYTES

SHADOW

ST72344S2 датащи(PDF) 168 Page - STMicroelectronics

ST72344S2 датащи(HTML) 168 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL