SPI Example?

Hello,

some sample code without comments,

it talkes to a dsp via spi interface, NIOS is MASTER and DSP is

slave

perhaps it helps

...# include"global.h"# include"system.h"# include"hw_base.h"

# include <unistd.h>

# include"dspctrl_spi.h"

# define INTWORD_DELAY 10

/*

void dsp_write16(WORD *data,WORD len) {

IOWR_ALTERA_AVALON_SPI_SLAVE_SEL(SPI_0_BASE,BIT0);

IOWR_ALTERA_AVALON_SPI_CONTROL(SPI_0_BASE, ALTERA_AVALON_SPI_CONTROL_SSO_MSK);

// spi_write_16(SPI_0_BASE,data,len);

IOWR_ALTERA_AVALON_SPI_SLAVE_SEL(SPI_0_BASE,BIT0);

IOWR_ALTERA_AVALON_SPI_CONTROL(SPI_0_BASE,0);

}

*/

# define SLAVE0 0# define HREGSIZE 32

//############################################################################

void dsp_write_reg(BYTE reg,WORD data) {

WORD tempdata[2];

tempdata[0]=CMD_FIRSTBYTE | (reg&(HREGSIZE-1));

tempdata[1]=data&~CMD_FIRSTBYTE;

// spi_write_16(base,tempdata[0]);

// spi_write_16(base,tempdata[1]);

spi_write_block(SPI_0_BASE,SLAVE0,tempdata,2);

spi_wait_TRDY(SPI_0_BASE);

}

//############################################################################

WORD dsp_read_reg(BYTE reg) {

WORD tempdata[2];

// dsp checks first byte and knows then that he has to put some data on the bus

tempdata[0]= CMD_FIRSTBYTE | CMD_READ | (reg&(HREGSIZE-1));

spi_write_block(SPI_0_BASE,SLAVE0,tempdata,1);

// spi_write_16(base,tempdata[0]);

spi_read_block(SPI_0_BASE,SLAVE0,tempdata,1);

return tempdata[0];

}

//############################################################################

void spi_write_block(DWORD base,BYTE slave,WORD *data,DWORD len) {

DWORD i;

for(i=0;i<len;i++) {

spi_select_slave(base,slave);

spi_write_16(base,(*data++));

spi_deselect_slave(base,slave);

usleep(INTWORD_DELAY);

}

}

//############################################################################

void spi_read_block(DWORD base,BYTE slave,WORD *data,WORD len) {

WORD i;

for(i=0;i<len;i++) {

spi_select_slave(base,slave);

*data++=spi_read_16(base);

spi_deselect_slave(base,slave);

usleep(INTWORD_DELAY);

}

}

//############################################################################

void spi_select_slave(DWORD base,DWORD slave) {

IOWR_ALTERA_AVALON_SPI_SLAVE_SEL(base, 1 << slave);

// Set the SSO bit (force chipselect)

IOWR_ALTERA_AVALON_SPI_CONTROL(base, ALTERA_AVALON_SPI_CONTROL_SSO_MSK);

}

//############################################################################

void spi_deselect_slave(DWORD base,DWORD slave) {

IOWR_ALTERA_AVALON_SPI_SLAVE_SEL(base, 1 << slave);

// reset the SSO bit (force chipselect)

IOWR_ALTERA_AVALON_SPI_CONTROL(base,0);

}

//############################################################################

void spi_write_16(DWORD base,WORD data) {

DWORD status;

do {

status = IORD_ALTERA_AVALON_SPI_STATUS(base);

} while ((status & ALTERA_AVALON_SPI_STATUS_TRDY_MSK) == 0);

IOWR_ALTERA_AVALON_SPI_TXDATA(base,data);

}

//############################################################################

WORD spi_read_16(DWORD base) {

DWORD status;

WORD data;

IORD_ALTERA_AVALON_SPI_RXDATA(base);

IOWR_ALTERA_AVALON_SPI_TXDATA(base,0x00);

do {

status = IORD_ALTERA_AVALON_SPI_STATUS(base);

} while ((status & ALTERA_AVALON_SPI_STATUS_RRDY_MSK) == 0);

data=IORD_ALTERA_AVALON_SPI_RXDATA(base);

return data;

}

/*

void spi_write_16(DWORD base,BYTE slave,WORD *data,DWORD len) {

DWORD i;

DWORD status;

IOWR_ALTERA_AVALON_SPI_SLAVE_SEL(base, 1 << slave);

for(i=0;i<len;i++) {

// select slave

IOWR_ALTERA_AVALON_SPI_CONTROL(base, ALTERA_AVALON_SPI_CONTROL_SSO_MSK);

do {

status = IORD_ALTERA_AVALON_SPI_STATUS(base);

} while ((status & ALTERA_AVALON_SPI_STATUS_TRDY_MSK) == 0);

// deselect slave

IOWR_ALTERA_AVALON_SPI_CONTROL(base, 0);

IOWR_ALTERA_AVALON_SPI_TXDATA(base,*data++);

}

while ((status & ALTERA_AVALON_SPI_STATUS_TRDY_MSK) == 0);

}

*/

void spi_wait_TRDY(DWORD base) {

DWORD status;

do {

status = IORD_ALTERA_AVALON_SPI_STATUS(base);

} while ((status & ALTERA_AVALON_SPI_STATUS_TRDY_MSK) == 0);

}