140 lines
4.0 KiB
C
Executable File
140 lines
4.0 KiB
C
Executable File
/*
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* spi_slave_recv_loop.c - SPI从设备持续接收程序
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*
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* 功能：SoC作为SPI从设备，配置与MCU主设备对齐，循环接收并打印数据
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* MCU每秒发送一帧（8字节）
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*
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* MCU主设备配置（需对齐）：
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* Mode : SPI_MODE_0 (CPOL=0, CPHA=0)
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* Bits/Word : 8
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* Speed : 1 MHz
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* 发送数据 : {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08}
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*
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* 编译：aarch64-linux-gnu-gcc -o spi_slave_recv_loop spi_slave_recv_loop.c
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* 运行：./spi_slave_recv_loop
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* 退出：按 Ctrl+C
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <sys/ioctl.h>
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#include <linux/spi/spidev.h>
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/* ========== SPI配置（必须与MCU主设备完全一致）========== */
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#define SPI_DEVICE "/dev/spidev4.0"
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#define SPI_MODE SPI_MODE_0 /* CPOL=1, CPHA=1 */
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#define SPI_BITS 8
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#define SPI_SPEED 1000000 /* 1MHz */
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#define FRAME_LEN 128 /* 每帧64字节 */
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/* ===================================================== */
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static volatile int keep_running = 1;
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void sigint_handler(int sig) {
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(void)sig;
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keep_running = 0;
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printf("\n[INFO] User interrupted, exiting...\n");
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}
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int main(void)
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{
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uint8_t buf[FRAME_LEN];
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int fd, ret;
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unsigned int frame_count = 0;
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/* 注册退出信号 */
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signal(SIGINT, sigint_handler);
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/* 1. 打开 SPI 设备 */
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fd = open(SPI_DEVICE, O_RDWR);
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if (fd < 0) {
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perror("open " SPI_DEVICE);
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return 1;
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}
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/* 2. 配置 SPI 模式 */
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uint8_t mode = SPI_MODE;
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mode |= SPI_LSB_FIRST;
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ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
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if (ret == -1) {
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perror("SPI_IOC_WR_MODE");
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close(fd);
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return 1;
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}
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/* 3. 配置每字位数 */
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uint8_t bits = SPI_BITS;
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ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
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if (ret == -1) {
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perror("SPI_IOC_WR_BITS_PER_WORD");
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close(fd);
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return 1;
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}
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/* 4. 配置最大时钟频率 */
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uint32_t speed = SPI_SPEED;
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ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
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if (ret == -1) {
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perror("SPI_IOC_WR_MAX_SPEED_HZ");
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close(fd);
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return 1;
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}
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/* 5. 回读验证配置 */
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ioctl(fd, SPI_IOC_RD_MODE, &mode);
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ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
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ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
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printf("========================================\n");
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printf("SPI Slave Config (aligned with MCU)\n");
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printf("========================================\n");
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printf("Device : %s\n", SPI_DEVICE);
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printf("Mode : %d (CPOL=%d, CPHA=%d)\n",
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mode, (mode & SPI_CPOL) ? 1 : 0, (mode & SPI_CPHA) ? 1 : 0);
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printf("Bits/Word : %d\n", bits);
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printf("Max Speed : %d Hz\n", speed);
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printf("Frame length: %d bytes\n", FRAME_LEN);
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printf("========================================\n");
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printf("Waiting for MCU (master) to send data...\n");
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printf("Press Ctrl+C to stop.\n\n");
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/* 6. 循环接收数据 */
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while (keep_running) {
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memset(buf, 0, FRAME_LEN);
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ret = read(fd, buf, FRAME_LEN);
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if (ret < 0) {
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perror("read");
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break;
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} else if (ret == 0) {
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/* 非阻塞模式可能返回0，但这里用了阻塞模式，一般不会出现 */
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//continue;
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}
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frame_count++;
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printf("\n========== Frame #%u (%d bytes) ==========\n", frame_count, ret);
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printf("HEX : ");
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for (int i = 0; i < ret; i++)
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printf("0x%02X ", buf[i]);
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printf("\n");
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printf("ASCII: ");
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for (int i = 0; i < ret; i++)
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printf(" %c ", (buf[i] >= 0x20 && buf[i] < 0x7F) ? buf[i] : '.');
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printf("\n");
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printf("DEC : ");
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for (int i = 0; i < ret; i++)
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printf("%3d ", buf[i]);
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printf("\n");
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printf("=========================================\n");
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}
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close(fd);
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return 0;
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}
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