Help with SPI code

[PicNewboy]

I have a problem with a SPI communication between two Pic18f4525
I try with a simple program,the master is the only pic that can use the serial 232 port,the slave make an operation(e.g a sum) and send back the result to master...How I make wrong?

Master Code:

#include <18f4525.h>
#device adc=10
#fuses H4,NOLVP,NOWDT,PUT,NOBROWNOUT
#use delay(clock=40000000)
#use rs232(baud=4800, xmit=PIN_C6, rcv=PIN_C7)

void init_spi(void)
{
setup_spi(SPI_MASTER | SPI_H_TO_L | SPI_CLK_DIV_16);
return;
}

void main(void)
{
int data=0;

init_spi();
printf("SPI test start.\r\n");
delay_ms(1500);

while (1) {
spi_write(data);
if (spi_data_is_in())
data=spi_read();
printf("M:data = %d\r\n", data);
}
}


Slave code:

void main(void)
{
int data=0;

init_spi();
while (1) {
if (spi_data_is_in())
data=spi_read();
spi_write(data+1);
}
}

Can anyone help me?Thank you.

[ckielstra]

The slave can never generate clock pulses, so the spi_write on the slave is depending on the master to generate the clock pulses, this can be achieved by either adding an extra spi_write in your master or by calling spi_read in the master with a value to be transmitted.

A nice example was posted a few days ago by Ttelmah: http://www.ccsinfo.com/forum/viewtopic.php?t=22416