SPI for nios

Hi edwin,

the main problem, which I encountered with SPI is the SPI enable. Sometimes when trying to send data it goes high or low. Sow it is best to use a dedicated enable PIO for SPI enable. This way it is possible to control it by yourself. It is difficult when you don&#39;t have altera_avalon_spi.h, but you&#39;ve got the control registers I think. Added to this message is my SPI-code, which I rewrote. It is better to use I think http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif . Good luck with it.... When you&#39;ve got any questions feel free to ask...

Cheers,

Danny

# define TMT (1 << 5) //Transmitter shift-register empty# define TRDY (1 << 6) //Transmitter ready# define RRDY (1 << 7) //Receiver ready# define spi_base SPI_0_BASE //Define SPI_base, less typing# define spi_cs SPI_0_CS_BASE //Define SPI_base, less typing

void spi_send(alt_u32 base,

const alt_u8 regBit,

const alt_u8 subRegBit)

{

IOWR_ALTERA_AVALON_SPI_CONTROL(base, 0x00); //Clear status register with zero&#39;s

while(~IORD_ALTERA_AVALON_SPI_STATUS(base) & TRDY); //check if tx data register is empty. If not, keep looping until it is

IOWR_ALTERA_AVALON_PIO_DATA(spi_cs, 0); //use this SPI-select, the one delivered by Altera doesn&#39;t work!!!

IOWR_ALTERA_AVALON_SPI_SLAVE_SEL(base, 0x01); //slave select mask enable, slave selection device 0

IOWR_ALTERA_AVALON_SPI_TXDATA(base, dummyBit); //write dummyBit to tx-buffer, so sending is possible

usleep(10); //Sleep for 10 useconds. Needed, otherwise SDI2RGB-board will NOT receive any commands

IOWR_ALTERA_AVALON_SPI_TXDATA(base, regBit); //write to tx-buffer

IOWR_ALTERA_AVALON_SPI_TXDATA(base, subRegBit); //write to tx-buffer

while(~IORD_ALTERA_AVALON_SPI_STATUS(base) & RRDY); //check if receiver is ready

while(~IORD_ALTERA_AVALON_SPI_STATUS(base) & TMT); //check if transmitter shift register is empty

IOWR_ALTERA_AVALON_PIO_DATA(spi_cs, 1); //use this SPI-select, the one delivered by Altera doesn&#39;t work!!!

}

/*

* Start of SPI_receive function, 1 parameter is given:

*

* Base

*/

alt_u8 spi_receive(alt_u32 base)

{

alt_u8 data; //Variable for SPI data to be stored in

IOWR_ALTERA_AVALON_PIO_DATA(spi_cs, 0); //use this SPI-select, the one delivered by Altera doesn&#39;t work!!!

while(~IORD_ALTERA_AVALON_SPI_STATUS(base) & TRDY); //check if tx data register is empty. If not, keep looping until it is

while(~IORD_ALTERA_AVALON_SPI_STATUS(base) & TMT); //check if transmitter shift register is empty

while(~IORD_ALTERA_AVALON_SPI_STATUS(base) & RRDY); //check if receiver is ready

data = 10; //variable for test-purpose

IOWR_ALTERA_AVALON_SPI_RXDATA(base, data); //read from RX-register

IOWR_ALTERA_AVALON_PIO_DATA(spi_cs, 1); //use this SPI-select, the one delivered by Altera doesn&#39;t work!!!

return data;

}