RM0319 datasheet(227/368 Pages) STMICROELECTRONICS

227 / 368 page

RM0319

I2C bus ports (I2C)

Doc ID 022640 Rev 3

227/368

Figure 82.

START and STOP conditions [from I2C-bus specification]

Addressing slave protocol

Two address formats are supported: the 7-bit address format and the 10-bit address format.

In case of the 7-bit address format, the first seven bits (bits 7 to 1) of the first byte sent on

the bus after the START condition set the slave address, while the LSB is the data direction

bit. In particular, if LSB is set to ‘b0, the master writes to the slave (WRITE operation),

otherwise (LSB set to ‘b1) the master reads from the slave (READ operation). Data is

transmitted from the MSB.

In case of 10-bit addressing, two bytes are transferred following a START condition to set

the 10-bit address. The first five bits (7 to 3) notify the slaves that this is a 10-bit transfer,

followed by the next two bits (2 to 1) which set the bits 9 and 8 of the 10-bit slave address.

The LSB of the first byte is the RW bit. Table 66 lists the special purpose and reserved first

byte addresses. The second byte transferred sets bits 7 to 0 of the 10-bit slave address.

Table 66.

First byte assignment in addressing slave protocol

First byte sent

Description

BIT [7:1]

RW BIT [0]

7’b0000 000

1‘h0

General call address. The I2C controller places the data in

the receive buffer and issues a general call interrupt

(Section 17.6).

7’b0000 000

1‘h1

START byte (see START byte transfer protocol section).

7’h0000 001

1’hX

CBUS address. The I2C controller ignores these accesses.

7’h0000 010

1’hX

Reserved

7’h0000 011

1’hX

Reserved

7’h0000 1XX

1’hX

High-speed master code

7’h1111 1XX

1’hX

Reserved

7’h1111 0XX

1’hX

10-bit slave addressing

SDA

SCL

START Condition

STOP Condition

RM0319 датащи(PDF) 227 Page - STMicroelectronics

RM0319 датащи(HTML) 227 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