Nxp Semiconductors UM10237 ユーザーズマニュアル

UM10237_2

© NXP B.V. 2008. All rights reserved.

 

 

This section provides examples of operations that must be performed by various I

2

C state 

service routines. This includes:

Initialization of the I

2

C block after a Reset.

I

2

C Interrupt Service.

The 26 state service routines providing support for all four I

2

C operating modes.

In the initialization example, the I

2

C block is enabled for both master and slave modes. 

For each mode, a buffer is used for transmission and reception. The initialization routine 
performs the following functions:

I2ADR is loaded with the part’s own slave address and the general call bit (GC).

The I

2

C interrupt enable and interrupt priority bits are set.

The slave mode is enabled by simultaneously setting the I2EN and AA bits in I2CON 
and the serial clock frequency (for master modes) is defined by loading CR0 and CR1 
in I2CON. The master routines must be started in the main program.

(1) Unsuccessful attempt to send a start condition.

(2) SDA line is released.

(3) Successful attempt to send a start condition. State 08H is entered.

SDA line

SCL line

STA flag

STO flag

time limit

start

condition

SDA line

SCL line

(1)

(2)

(1)

(3)

STA flag

start

condition