feat(spi):update spi

source/soa_server/spi_server.cpp

@@ -75,8 +75,10 @@ void my_spi_server_thread_func(void* arg) {
 
 
     uint8_t buf[FRAME_LEN];
+    uint8_t last_buf[FRAME_LEN] = {0};
     int fd, ret;
     unsigned int frame_count = 0;
+    int data_changed = 0;
 
     /* 注册退出信号 */
     signal(SIGINT, sigint_handler);
@@ -137,17 +139,29 @@ void my_spi_server_thread_func(void* arg) {
     /* 6. 循环接收数据 */
     while (keep_running) {
         memset(buf, 0, FRAME_LEN);
-        ret = read(fd, buf, FRAME_LEN);
-        if (ret < 0) {
-            perror("read");
-            break;
-        } else if (ret == 0) {
-            /* 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 */
-            //continue;
-        }
 
-        
+        struct spi_ioc_transfer tr = {
+            .tx_buf        = (unsigned long)NULL,
+            .rx_buf        = (unsigned long)buf,
+            .len           = FRAME_LEN,
+            .speed_hz      = SPI_SPEED,
+            .bits_per_word = SPI_BITS,
+        };
+        ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
+        if (ret < 0) {
+            perror("spi transfer");
+            break;
+        }
+        ret = FRAME_LEN;  /* transfer 成功则返回 FRAME_LEN */
+
         frame_count++;
+
+        /* 判断数据是否有变化 */
+        data_changed = (memcmp(last_buf, buf, FRAME_LEN) != 0);
+        if (!data_changed)
+            continue;
+        memcpy(last_buf, buf, FRAME_LEN);
+
         printf("\n========== Frame #%u (%d bytes) ==========\n", frame_count, ret);
         printf("HEX  : ");
         for (int i = 0; i < ret; i++)