cpld的通訊格式會有不同
我這使用的是32bit 需反轉(zhuǎn)的
寫時序：

讀時序：

#include <stdint.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <getopt.h> #include <fcntl.h> #include <sys/ioctl.h> #include <linux/types.h> #include <linux/spi/spidev.h>static void pabort(const char *s) {perror(s);abort(); }static uint32_t mode ; static uint8_t bits = 8; static uint32_t speed = 100000; static uint16_t delay;uint8_t default_rx[5] = {0};unsigned char bit_reverse8(unsigned char c) {return ((c >> 7) & 0x1)|( (c << 7) & 0x80) \| ((c >> 5) & 0x2)|( (c << 5) & 0x40) \| ((c >> 3) & 0x4)|( (c << 3) & 0x20) \| ((c >> 1) & 0x8)|( (c << 1) & 0x10) ; }static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len) {int ret;struct spi_ioc_transfer tr = {.tx_buf = (unsigned long)tx,.rx_buf = (unsigned long)rx,.len = len,.delay_usecs = delay,.speed_hz = speed,.bits_per_word = bits,};ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);if (ret < 1)printf("can't send spi message\n"); }/************** cpld 讀寫接口 **************/ static int cpld_init(void) {int fd, ret = 0;char *device = "/dev/spidev0.2";fd = open(device, O_RDWR);if (fd < 0)pabort("can't open device");ret = ioctl(fd, SPI_IOC_WR_MODE32, &mode);if (ret == -1)pabort("can't set spi mode");ret = ioctl(fd, SPI_IOC_RD_MODE32, &mode);if (ret == -1)pabort("can't get spi mode");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");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");#if 0printf("open:%s\n", device);printf("cpld:spi mode: 0x%x\n", mode);printf("cpld:bits per word: %d\n", bits);printf("cpld:max speed: %d Hz (%d KHz)\n", speed, speed/1000); #endifreturn fd; }uint8_t cpld_write(uint8_t reg, uint8_t data_out) {int fd;fd = cpld_init();uint8_t default_tx[] = {bit_reverse8(0x51), bit_reverse8(reg), 0, bit_reverse8(data_out)};transfer(fd, default_tx, default_rx, sizeof(default_tx));printf("cpld write: reg=0x%x data_out=0x%x\n", reg, data_out);close(fd);return 0; }uint8_t cpld_read(uint8_t reg) {uint8_t data_in[2] = {0};int fd;fd = cpld_init();uint8_t default_tx[] = {bit_reverse8(0x50), bit_reverse8(reg&0xff), 0, 0};transfer(fd, default_tx, default_rx, sizeof(default_tx));#if 0printf("default_tx: 0x%x 0x%x 0x%x 0x%x\n", default_tx[0], default_tx[1], default_tx[2], default_tx[3]);printf("default_rx: %4x %4x %4x %4x\n", default_rx[0], default_rx[1], default_rx[2], default_rx[3]); #endifdata_in[0] = bit_reverse8(default_rx[3]);data_in[1] = bit_reverse8(default_rx[2]);printf("cpld read: reg=0x%x data_in=0x%x\n", reg, data_in[0]);close(fd);return data_in[0]; }/************** main **************/ int main(int argc, char *argv[]) {uint8_t reg, cpld_data_in, data_out = 0x00;printf("text by fish.\n");if(2 == argc){reg = strtoul(argv[1], NULL, 16);cpld_data_in = cpld_read(reg);}else if(3 == argc){reg = strtoul(argv[1], NULL, 16);data_out = strtoul(argv[2], NULL, 16);cpld_data_in = cpld_read(reg);cpld_write(reg, data_out);cpld_data_in = cpld_read(reg);}else{printf("./spi_cpld [reg] [data_out]\n");}return 0; }

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