help me on my first program with SPI

[filjoa]

Hi

I like start my study on SPI communication, but I don’t understand some questions.
For example,
Is possible I transmit a string between two PICs?
Someone can explain me how I can make this “simple” example.
On PIC master I have two switches connected on PIN_C0 and PIN_C1, and on slave PIC I have one led on PIN_B7. I like if I press PIN_C0 led turn-on, if I press PIN_C1 led turn-off.
But I like witch when I press PIN_C0 write slave PIC an string “ON” if a press PIN_C1 write on slave PIC a string “OFF”, and after read by slave it make operation.

If is possible help me make this little program for I can start used this protocol…

PS: I used PIC18F252

Best regards

[PCM programmer]

See these threads for sample code:
http://www.ccsinfo.com/forum/viewtopic.php?t=39145
http://www.ccsinfo.com/forum/viewtopic.php?t=26888
They show how to send and receive bytes between two PICs,
with one PIC as the SPI master and the other PIC as the SPI slave.

[filjoa]

Hi

thanks PCM Programmer, in your 1ª link in slave PIC, if I choose on Master charter 'A' (read ADC) it wait for adc result from slave PIC, correct? but where slave PIC stay write to master?

I don't understand this.... slave PIC don't need some like spi_write()?

best regards

[PCM programmer]

The slave is writing directly to the SPI buffer register. Example:

[filjoa]

Hi

In "#byte SSPBUF = 0x13"? How I know register on 18F252?

But master go there read? Slave don't need send information to master?

best regards

[PCM programmer]