this is the programme that i use to interface SPI with shift register . i use Apex 20k200e .
# include "excalibur.h"
int main ( )
{
int i;
int data_1 = 0x79;
for (i = 0; i < 100 ; ++i)
{
// Transmit a byte:
while (!(na_spi->np_spistatus & np_spistatus_trdy_mask));
na_spi->np_spitxdata = data_1;
// Read and throw away the received data:
while (!(na_spi->np_spistatus & np_spistatus_rrdy_mask));
na_spi->np_spirxdata;
}
//nr_delay(1000);
// Wait until the last byte is transmitted:
while (!(na_spi->np_spistatus & np_spistatus_tmt_mask));
// Release SS_n:
na_spi-> np_spicontrol &=~np_spicontrol_sso_mask;
}
but the problem is my shift register still no output. can anyone recomment me any comment about programme.
