AN1045 Просмотр технического описания (PDF) - STMicroelectronics

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AN1045

ST7 S/W IMPLEMENTATION OF I2C BUS MASTER

STMicroelectronics 

ST7 S/W IMPLEMENTATION OF I2C BUS MASTER

SetBit(I2C_SR2,AF);

ClrBit(I2C_SR1,ACK);

return;

}

delay(1);

if (ValBit(PADR,SDA))

/* Test of SDA level, if high -> pb */

{

SetBit(I2C_SR2,AF);

ClrBit(I2C_SR1,ACK);

return;

}

delay(1);

SetBit(PADDR,SCL);

/* End of the clock pulse

*/

SetBit(I2C_SR1,ACK);

delay(1);

ClrBit (PADR,SDA);

SetBit(PADDR,SDA);

/* Reconfigure SDA as output to proceed at the next transmission */

}

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

ROUTINE NAME : I2C_nAck

INPUT/OUTPUT : None.

DESCRIPTION : Non acknoledge generation from now.

COMMENTS : Transfer sequence = DATA, NACK.

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

void I2C_nAck (void)

{

ClrBit(I2C_SR2,ACK); /* Non acknoledge when the master is receiver */

SetBit(PADR,SDA); /* The master pulls the SDA line high

*/

SetBit(PADDR,SCL); /* Output open drain to have a low level */

delay(10);

ClrBit(PADDR,SCL); /* The master generates a clock pulse

*/

delay(10);

SetBit(PADDR,SCL); /* Clock pulse complete

*/

ClrBit(PADR,SDA); /* The master pulls the SDA line high

*/

delay(3);

}

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

ROUTINE NAME : I2Cm_Init

INPUT/OUTPUT : None.

DESCRIPTION : I2C peripheral initialisation routine.

COMMENTS : Contains inline assembler instructions in C like mode !

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

void I2Cm_Init (void)

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