PIC 16F877. Implementation of i2c master with interrupt.

[Renato and Davide]

Hello at everybody,
we have wrote this code:

#USE I2C(master, sda=PIN_C4, scl=PIN_C3, SLOW, NOFORCE_SW)

int i=0;

void main ()
{
i2c_start ();
}

#INT_SSP
void master()
{
i2c_write (buffer[i]); //buffer[0] = 0x0E (slave address)
if (i==21) i2c_stop ();
i++;
}

* The problem is that the instruction i2c_start() in main provokes an interrupt, but the i2c_write () doesn't cause interrupt, is it correct ? If it is correct what is the usefullness?

* We have seen that the i2c_write () returns 0 (ACK) when the slave address is correct, but this not cause new interrupt.

* We had test that if the instruction i2c_write is located in main it cause the interrupt:

void main ()
{
i2c_start (); //cause the interrupt
i2c_write (); //cause the interrupt
}

We do not understand the usefullness.

IDE Version = 2.32
PCB Version = 3.043
PCM Version = 3.043
Thank you for the support. Best regards
___________________________
This message was ported from CCS's old forum
Original Post ID: 1352

[Tomi]

Bon giorno,
the i2c_write() function includes a wait state after moving the byte into SSPBUF (it waits for the end of the write cycle).
Try this instead of "i2c_write(buffer[i])" line:

bit_set(*0x14,4); // optional:the clock polarity instruction if it is necessary
*0x13 = buffer[i]; // direct write into SSPBUF

:=Hello at everybody,
:=we have wrote this code:
:=
:=#USE I2C(master, sda=PIN_C4, scl=PIN_C3, SLOW, NOFORCE_SW)
:=
:=int i=0;
:=
:=void main ()
:={
:= i2c_start ();
:=}
:=
:=#INT_SSP
:=void master()
:={
:= i2c_write (buffer[i]); //buffer[0] = 0x0E (slave address)
:= if (i==21) i2c_stop ();
:= i++;
:=}
:=
:=* The problem is that the instruction i2c_start() in main provokes an interrupt, but the i2c_write () doesn't cause interrupt, is it correct ? If it is correct what is the usefullness?
:=
:=* We have seen that the i2c_write () returns 0 (ACK) when the slave address is correct, but this not cause new interrupt.
:=
:=* We had test that if the instruction i2c_write is located in main it cause the interrupt:
:=
:=void main ()
:={
:= i2c_start (); //cause the interrupt
:= i2c_write (); //cause the interrupt
:=}
:=
:=We do not understand the usefullness.
:=
:=IDE Version = 2.32
:=PCB Version = 3.043
:=PCM Version = 3.043
:=Thank you for the support. Best regards
___________________________
This message was ported from CCS's old forum
Original Post ID: 1356