Forum Discussion
C code question !! / NIOS II / SPI interface
Hello,
I have a question about implementing the spi interface in a FPGA, I already constructed a working CPU with a implementation of the SPI, and added the correct settings in SOIC, however i have a problem with my code for the niosII proccesor, for some reason it jumps right over my written code, it jumps straigt to the end of the main() function, I am as you would say a nOOb in programming... so i think i just made a stupid mistake in my code, but I cannot locate it... Below states the code that i have written, for testing purpose's my idea was to send 0xFF a thousand times.... however when i go in debug mode it goes into int alt_avalon_spi_command(alt_u32 base, alt_u32 slave,......) and after that it jumps strait to the end without execucution the code under it. The development board is a NIOS development board, Cyclone I edition... I hope one of you could explain what i am doing wrong !! :confused: Thanks a lot !! :) greetings, Remko # include <stdio.h># include <system.h># include <altera_avalon_pio_regs.h> //#include <altera_avalon_pwm_routines.h> //#include <altera_avalon_uart_regs.h># include <string.h># include <sys/alt_alarm.h># include <alt_types.h># include <sys/time.h># include <fcntl.h> //SPI headers# include <altera_avalon_spi_regs.h># include <altera_avalon_spi.h> int delay_1(); int spi(); int main() { int alt_avalon_spi_command(alt_u32 base, alt_u32 slave, alt_u32 write_length, const alt_u8* wdata, alt_u32 read_length, alt_u8* read_data, alt_u32 flags) { int i; // force SS_N active IOWR_ALTERA_AVALON_SPI_CONTROL(base, ALTERA_AVALON_SPI_CONTROL_SSO_MSK); for (i = 0; i<10000 ; ++i) { // transmit a byte while (!(IORD_ALTERA_AVALON_SPI_STATUS(base) & ALTERA_AVALON_SPI_STATUS_TRDY_MSK)); IOWR_ALTERA_AVALON_SPI_TXDATA(base, 0xFF); // wait for all bytes to be send while(!(IORD_ALTERA_AVALON_SPI_STATUS(base) & ALTERA_AVALON_SPI_STATUS_TMT_MSK)); } //release SS_N IOWR_ALTERA_AVALON_SPI_CONTROL(base, ~ALTERA_AVALON_SPI_CONTROL_SSO_MSK); } delay_1(); } int delay_1() { int count = 0; int delay; while(1) { IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, count & 0x03); IOWR_ALTERA_AVALON_PIO_DATA(SEVEN_SEG_PIO_BASE, count & 0xff); delay = 0; while(delay < 200000) { delay++; } count++; } }14 Replies
- Altera_Forum
Honored Contributor
Why do you define a alt_avalon_spi_command function inside main()?
Just put your code directly inside main() and it will run. I didn't even know this was legal in C... - Altera_Forum
Honored Contributor
Thanks for the quick reply !! Well, thats a example .c file didint knew that would be a problem. But i don't quite understand what you mean by putting it int main(), if I define alt_avalon_spi_command () somewhere else than in main(); the code will not be accepted as then it will not reconise functions as IOWR_ALTERA_AVALON_SPI_CONTROL(base); I dont fully understandt the alt_avalon_spi_command(), although i have read the software reference, could you maybe give me a example CTRL+C, CTRL+V of my code by what you meant by putting the code inside main()... I have tried it but it didn't work for me...
- Altera_Forum
Honored Contributor
Hey, kind of funny to reply to my own thread :p, but i have solved the problem! just as you suggested i can't define alt_avalon_spi_command function inside main()... stupid me... it was already defined in the header file... stupid mistake....
thanks again for your reply ! greets, remko - Altera_Forum
Honored Contributor
Hi, I read your code and it´s the only help about programming a SPI interface on a DE2... my question is if you can post your final code, because I have huge problems with programming it at NIOS eclipse and it will be a huge help to me... thanks for your time and help... :)
- Altera_Forum
Honored Contributor
Hello, that's a long time ago, I need to find it first ;), but that won't be a problem, I will post it as soon as I can :)
- Altera_Forum
Honored Contributor
Hi there, after a lot of searching i have found the code you requested :)
The data is sent 1 byte at a time, i have called it data, good luck with it ;) int SPI (int data) { /* * Discard any stale data present in the RXDATA register, in case * previous communication was interrupted and stale data was left * behind. */ IORD_ALTERA_AVALON_SPI_RXDATA(SPI_0_NVRAM_BASE); // initiate SS_N IOWR_ALTERA_AVALON_SPI_CONTROL(SPI_0_NVRAM_BASE, ALTERA_AVALON_SPI_CONTROL_SSO_MSK); // transmit a byte, set write enable latch while (!(IORD_ALTERA_AVALON_SPI_STATUS(SPI_0_NVRAM_BASE) & ALTERA_AVALON_SPI_STATUS_TRDY_MSK)); IOWR_ALTERA_AVALON_SPI_TXDATA(SPI_0_NVRAM_BASE, data); // wait for all bytes to be send while(!(IORD_ALTERA_AVALON_SPI_STATUS(SPI_0_NVRAM_BASE) & ALTERA_AVALON_SPI_STATUS_TMT_MSK)); // release SS_N IOWR_ALTERA_AVALON_SPI_CONTROL(SPI_0_NVRAM_BASE, ~ALTERA_AVALON_SPI_CONTROL_SSO_MSK); } - Altera_Forum
Honored Contributor
how can i clean the LCD ? is there any function?
- Altera_Forum
Honored Contributor
Hi... thanks about the code... but it is only a function? or is a entire c program? well I need to send a byte to a slave, but I don´t know what "includes" put in my main code... if you know about it, please tell me... :)
- Altera_Forum
Honored Contributor
Hi,
I would like o implement SPI with NIOS II in Qsys. I want NIOS to read and write data from a memory outside with SPI interface. Does this code work? I think it only sends data and while sending data to the memory is this function is enough and you don't deal with addresses and stuff. Thanks - Altera_Forum
Honored Contributor
There is also a register you can use to read back the data that was received from the SPI bus. Have a look at the SPI IP documentation.
The SPI IP just sends and reads back a bunch of bits. It has no idea about the protocol underneath and you need to do it yourself. So to deal with "addresses and stuff", have a look at your SPI memory datasheet and see how you should implement the protocol.