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ST7 S/W IMPLEMENTATION OF I2C BUS MASTER

SetBit(PADDR,SDA);

delay(10);

ClrBit(PADDR,SCL);

/* Waits the master takes the control of SDA */

delay(10);

SetBit(PADDR,SCL);

delay(5);

ClrBit(PADDR,SDA);

/* The master releases the SDA line

*/

SetBit(I2C_SR1,ACK);

/* ACK=1: Acknowledge sent by the master

*/

}

/*--------------------------------------------------------------------------

ROUTINE NAME : I2Cm_Tx

INPUT/OUTPUT : send_tab and n, the number of data to transmit (with 2 addresses)

/ None.

DESCRIPTION : Transmit data buffer.

COMMENTS

: Most significant bytes first.

--------------------------------------------------------------------------*/

void I2Cm_Tx (char * buffout,char nb)

{

SetBit(PADDR,SDA);

/* Configure SDA as an output to send data

*/

for (j=nb;j!=0xFF;j--)

{

/* 2 addresses and 3 data to send: from X=n downto X=0

*/

flag=0;

if ((j==(nb-2))&&(ValBit(I2C_SR1,RCPT)))

{

I2Cm_Start();

/* Start condition

*/

j=nb;

/* EEPROM @ with the LSB at 1 to send

*/

flag=1;

}

count=1;

I2C_DR=buffout[j];

if (flag==1) I2C_DR=I2C_DR|1;

/* If master receiver, the address to send is A1

*/

do

{

I2Cm_TxData();

/* Sending of data bit per bit, MSB first

*/

count*=2;

}while(count!=0);

wait_Ack();

/* Wait ACK from the slave

*/

if(!ValBit(I2C_SR1,ACK))

SetBit(I2C_SR2,AF);