Hi all,
I am beginner with the BeagleBone Black board and I have a problem with the
SPI communication.
I am trying to communicate with the Redpine wifi board by SPI. The
BeagleBone Black is the master and the wifi board is the slave.
Part of the configuration of my BB-SPI0DEV-00A0.dts is the follow:
/* state the resources this cape uses */
exclusive-use =
/* the pin header uses */
"P9.17", /* spi0_cs0 */
"P9.18", /* spi0_d1 MOSI */
"P9.21", /* spi0_d0 MISO*/
"P9.22", /* spi0_sclk */
/* the hardware ip uses */
"spi0";
fragment@0 {
target = <&am33xx_pinmux>;
__overlay__ {
bb_spi0_pins: pinmux_bb_spi0_pins {
pinctrl-single,pins = <
0x150 0x10 /* spi0_sclk.spi0_sclk, OUTPUT_PULLUP |
MODE0 */
0x154 0x30 /* spi0_d0.spi0_d0, INPUT_PULLUP | MODE0 */
0x158 0x10 /* spi0_d1.spi0_d1, OUTPUT_PULLUP | MODE0 */
0x15c 0x10 /* spi0_cs0.spi0_cs0, OUTPUT_PULLUP | MODE0
*/
>;
};
};
};
I made all the configuration for the SPI and I am trying to execute the
spidev_test exemple.
I am using the osciloscophe, so I can see that the message sent and
received are corrects!
I am sendding 0x15 0x00 and receiving 0x00 0x58, but in the program, the
receive rx only shows me 0x00 0x00.
Somebody can help me to find what I am doing wrong? If the osciloscope
shows me the correct signal for the send, receive, clock and CS. What could
be wrong in my SPI configuration? I tried so many configurations, I dont
know if I am setting wrong the ioctl.
Spidev_test exemplo:
#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;
static uint8_t bits = 8;
static uint32_t speed = 500000;
static uint16_t delay = 0;
static void transfer(int fd)
{
int ret;
uint8_t tx[] = {
0x15, 0x00,
};
uint8_t rx[ARRAY_SIZE(tx)] = {0, };
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long)tx,
.rx_buf = (unsigned long)rx,
.len = ARRAY_SIZE(tx),
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
};
ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
if (ret < 1)
pabort("can't send spi message");
for (ret = 0; ret < ARRAY_SIZE(tx); ret++) {
if (!(ret % 6))
puts("");
printf("%.2X ", rx[ret]);
}
puts("");
}
int main(int argc, char *argv[])
{
int ret = 0;
int fd;
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;
}
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