Robot Control Library
* @example rc_spi_loopback.c
* This is a test to check read and write operation of the SPI1 bus. For this
* example to work, connect the MISO and MOSI wires of one of the included 6-pin
* JST-SH pigtails and plug into either SPI1 socket. The test strings this
* programs transmits out the MOSI channel will loop back in the MISO channel
* and be read.
#include <stdio.h>
#include <string.h>
#include <rc/spi.h>
// change these for your platform
// on BB this is equivilant to RC_BB_SPI1_SS1
#define BUS 1
#define SLAVE 0
#define SPI_SPEED 24000000
int main()
char* test_str = "Hello World";
// get number of bytes in test string, add 1 for the terminating null
// character which strlen omits
int bytes = strlen(test_str)+1;
char buf[32]; // read buffer
int ret; // return value
printf("Make sure the MISO and MOSI lines are connected with\n");
printf("a loopback jumper which is necessary for this test.\n");
printf("Testing SPI \n\n");
if(rc_spi_init_auto_slave(BUS, SLAVE, BUS_MODE, SPI_SPEED)){
return -1;
// attempt a string send/receive transfer
printf("transfer test:\n");
printf("Sending %d bytes: %s\n", bytes, test_str);
ret = rc_spi_transfer(BUS, SLAVE, (uint8_t*)test_str, bytes, (uint8_t*)buf);
printf("send failed\n");
return -1;
else printf("Received %d bytes: %s\n",ret, buf);\
return 0;