Hello,
I am working with the Eagle board from Diamond System that has Apalis imx6 on it and I would like to communicate with SPI component LTC1858 using /dev/spidev1.0. The TX nb of bits is 8 and the RX nb of bits is 14.
It seems like I can kind of get data back from the component (I checked with an oscilloscope, what I see is what I get, I can't check again until Friday), it's just that the values sent back are not what I am expecting. I'm wondering if maybe the configuration is sent wrong.... Not sure how to deal with the TX 8 bit and RX 14 bit business... I haven't done anything with CS. Is there something wrong with the code I have been using? Is there a library I could use instead?
Best regards,
Jennifer
/*
* SPI testing utility (using spidev driver)
*
* Copyright (c) 2007 MontaVista Software, Inc.
* Copyright (c) 2007 Anton Vorontsov <avorontsov@ru.mvista.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License.
*
* Cross-compile with cross-gcc -I/path/to/cross-kernel/include
*/
#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
static void pabort(const char *s)
{
perror(s);
abort();
}
static const char *device = "/dev/spidev1.0";
static uint8_t mode=0;
static uint8_t bits = 8;
static uint32_t speed = 1000;
static uint16_t delay ;
static void printHexToBinary(uint16_t hex)
{
switch (hex)
{
case 0: printf("0000");
break;
case 1: printf("0001");
break;
case 2: printf("0010");
break;
case 3: printf("0011");
break;
case 4: printf("0100");
break;
case 5: printf("0101");
break;
case 6: printf("0110");
break;
case 7: printf("0111");
break;
case 8: printf("1000");
break;
case 9: printf("1001");
break;
case 10: printf("1010");
break;
case 11: printf("1011");
break;
case 12: printf("1100");
break;
case 13: printf("1101");
break;
case 14: printf("1110");
break;
case 15: printf("1111");
break;
default: break;
}
}
static void transfer(int fd)
{
int ret;
uint8_t tx[] = {
( 0xAC )
};
uint8_t rx[2] = {0, };
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long)tx,
.rx_buf = (unsigned long)rx,
.len = ARRAY_SIZE(rx),
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = 8,
};
ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
if (ret < 1)
pabort("can't send spi message");
for (ret = 0; ret < ARRAY_SIZE(rx); ret++) {
// if (!(ret % 6))
// puts("");
printf("%.2X ", rx[ret]);
}
printf("\r\n");
uint16_t total = (rx[0] << 8) + rx[1];
printf("%d\r\n", total);
printHexToBinary(rx[0]>>4);
printHexToBinary(rx[0] & 0x0f);
printHexToBinary((rx[1]>>4) & 0x0f);
printHexToBinary(rx[1] & 0x0f);
printf("\r\nvoltage: %f", (double)total*10/(4*16383));
puts("");
}
static void print_usage(const char *prog)
{
printf("Usage: %s [-DsbdlHOLC3]\n", prog);
puts(" -D --device device to use (default /dev/spidev1.1)\n"
" -s --speed max speed (Hz)\n"
" -d --delay delay (usec)\n"
" -b --bpw bits per word \n"
" -l --loop loopback\n"
" -H --cpha clock phase\n"
" -O --cpol clock polarity\n"
" -L --lsb least significant bit first\n"
" -C --cs-high chip select active high\n"
" -3 --3wire SI/SO signals shared\n");
exit(1);
}
static void parse_opts(int argc, char *argv[])
{
while (1) {
static const struct option lopts[] = {
{ "device", 1, 0, 'D' },
{ "speed", 1, 0, 's' },
{ "delay", 1, 0, 'd' },
{ "bpw", 1, 0, 'b' },
{ "loop", 0, 0, 'l' },
{ "cpha", 0, 0, 'H' },
{ "cpol", 0, 0, 'O' },
{ "lsb", 0, 0, 'L' },
{ "cs-high", 0, 0, 'C' },
{ "3wire", 0, 0, '3' },
{ "no-cs", 0, 0, 'N' },
{ "ready", 0, 0, 'R' },
{ NULL, 0, 0, 0 },
};
int c;
c = getopt_long(argc, argv, "D:s:d:b:lHOLC3NR", lopts, NULL);
if (c == -1)
break;
switch (c) {
case 'D':
device = optarg;
break;
case 's':
speed = atoi(optarg);
break;
case 'd':
delay = atoi(optarg);
break;
case 'b':
bits = atoi(optarg);
break;
case 'l':
mode |= SPI_LOOP;
break;
case 'H':
mode |= SPI_CPHA;
break;
case 'O':
mode |= SPI_CPOL;
break;
case 'L':
mode |= SPI_LSB_FIRST;
break;
case 'C':
mode |= SPI_CS_HIGH;
break;
case '3':
mode |= SPI_3WIRE;
break;
case 'N':
mode |= SPI_NO_CS;
break;
case 'R':
mode |= SPI_READY;
break;
default:
print_usage(argv[0]);
break;
}
}
}
int main(int argc, char *argv[])
{
int ret = 0;
int fd;
parse_opts(argc, argv);
fd = open(device, O_RDWR);
if (fd < 0)
pabort("can't open device");
/*
* spi mode
*/
ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
if (ret == -1)
pabort("can't set spi mode");
ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
if (ret == -1)
pabort("can't get spi mode");
/*
* bits per word
*/
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't set bits per word");
ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't get bits per word");
/*
* max speed hz
*/
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't set max speed hz");
ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't get max speed hz");
printf("spi mode: %d\n", mode);
printf("bits per word: %d\n", bits);
printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);
transfer(fd);
close(fd);
return ret;
}
