esp32开发与应用（串口测试）

【 声明版权所有欢迎转载请勿用于商业用途。 联系信箱feixiaoxing 163.com】esp32板子上面有两个串口一个是串口0一个是串口2。其中串口0是用做下载image使用的所以不建议大家使用。所以剩下来的串口2是大家非常推荐的串口。今天就来看看esp32里面串口是怎么使用的。1、三个串口只能用1个按照官方的资料说本身esp32是有多个串口的但是0和1串口要么被当下载口要么经常被占用。实际使用的最多的还是串口2。2、测试方法这里的测试方法比较简单就是一个自环测试。即所有tx发出来的内容都会流到rx这边。所以我们需要做的就是找一根杜邦线把两者连在一起即可。3、实际使用方法实际使用就和常规的串口一样tx/rx/gnd。比如说假设需要esp32和stm32或者是其他arm soc系统进行连接那么直接tx/rx交叉对接即可。注意连接的时候最好gnd也加上。4、用ai写代码所有条件都准备好了就可以让ai写代码。比如告诉ai用esp-idf编写一个esp32的串口自环程序。不出意外的话就能看到这样的结果// uart2_loopback_external.c // External loopback test - Requires shorting GPIO16 and GPIO17 with a jumper wire #include stdio.h #include string.h #include freertos/FreeRTOS.h #include freertos/task.h #include driver/uart.h #include driver/gpio.h #include esp_log.h // Macro definitions #define UART_PORT_NUM UART_NUM_2 #define UART_TX_PIN GPIO_NUM_17 #define UART_RX_PIN GPIO_NUM_16 #define BUF_SIZE 1024 #define TEST_INTERVAL_MS 2000 static const char *TAG UART2_EXT_LOOPBACK; // Send string and read echo back void uart2_echo_test(void) { char *test_str Hello UART2! This is a loopback test message.\n; char rx_buffer[BUF_SIZE]; while (1) { // Clear buffer memset(rx_buffer, 0, sizeof(rx_buffer)); // Send test message int tx_len uart_write_bytes(UART_PORT_NUM, test_str, strlen(test_str)); ESP_LOGI(TAG, Sent %d bytes: %s, tx_len, test_str); // Wait for data to return vTaskDelay(pdMS_TO_TICKS(100)); // Read received data int rx_len uart_read_bytes(UART_PORT_NUM, (uint8_t *)rx_buffer, BUF_SIZE - 1, pdMS_TO_TICKS(500)); if (rx_len 0) { rx_buffer[rx_len] \0; // Verify data consistency if (strcmp(test_str, rx_buffer) 0) { ESP_LOGI(TAG, ✓ Echo test PASSED - received: %s, rx_buffer); } else { ESP_LOGW(TAG, ✗ Echo test FAILED - sent: %s, test_str); ESP_LOGW(TAG, received: %s, rx_buffer); } } else { ESP_LOGW(TAG, ✗ Echo test FAILED - no data received); ESP_LOGW(TAG, Please check: Are GPIO%d and GPIO%d shorted?, UART_TX_PIN, UART_RX_PIN); } vTaskDelay(pdMS_TO_TICKS(TEST_INTERVAL_MS)); } } // Byte-level loopback test (more precise verification) void uart2_byte_loopback_test(void) { uint8_t tx_data[BUF_SIZE]; uint8_t rx_data[BUF_SIZE]; // Initialize test data (0-255 cycle) for (int i 0; i BUF_SIZE; i) { tx_data[i] i % 256; } int test_count 0; int success_count 0; while (1) { test_count; // Send data uart_write_bytes(UART_PORT_NUM, (const char *)tx_data, BUF_SIZE); // Wait for data to return vTaskDelay(pdMS_TO_TICKS(100)); // Read data int rx_len uart_read_bytes(UART_PORT_NUM, rx_data, BUF_SIZE, pdMS_TO_TICKS(500)); if (rx_len BUF_SIZE) { bool match memcmp(tx_data, rx_data, BUF_SIZE) 0; if (match) { success_count; ESP_LOGI(TAG, Test #%d: ✓ PASSED (%d bytes matched), test_count, rx_len); } else { // Find the first mismatched position for (int i 0; i BUF_SIZE; i) { if (tx_data[i] ! rx_data[i]) { ESP_LOGE(TAG, Mismatch at offset %d: 0x%02X ! 0x%02X, i, tx_data[i], rx_data[i]); break; } } } } else { ESP_LOGW(TAG, Test #%d: ✗ FAILED (expected %d bytes, got %d), test_count, BUF_SIZE, rx_len); } ESP_LOGI(TAG, Success rate: %d/%d (%.1f%%), success_count, test_count, (float)success_count * 100 / test_count); vTaskDelay(pdMS_TO_TICKS(TEST_INTERVAL_MS)); } } void app_main(void) { ESP_LOGI(TAG, ESP32 UART2 External Loopback Test ); ESP_LOGI(TAG, Hardware: Please short GPIO%d (TX) and GPIO%d (RX), UART_TX_PIN, UART_RX_PIN); // 1. Configure UART parameters uart_config_t uart_config { .baud_rate 115200, .data_bits UART_DATA_8_BITS, .parity UART_PARITY_DISABLE, .stop_bits UART_STOP_BITS_1, .flow_ctrl UART_HW_FLOWCTRL_DISABLE, .source_clk UART_SCLK_APB, }; ESP_ERROR_CHECK(uart_param_config(UART_PORT_NUM, uart_config)); // 2. Set pins ESP_ERROR_CHECK(uart_set_pin(UART_PORT_NUM, UART_TX_PIN, UART_RX_PIN, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE)); // 3. Install driver (Note: hardware loopback is NOT enabled here) const int uart_buffer_size BUF_SIZE * 2; ESP_ERROR_CHECK(uart_driver_install(UART_PORT_NUM, uart_buffer_size, uart_buffer_size, 10, NULL, 0)); ESP_LOGI(TAG, UART2 initialized successfully); ESP_LOGI(TAG, Starting echo test...); // Run test (choose one) //uart2_echo_test(); uart2_byte_loopback_test(); }官方给了两个测试函数一个是uart2_echo_test还有一个是uart2_byte_loopback_test。实际测试的时候只需要放开一个。5、编译、下载和测试编译的时候只需要放开一个测试函数即可。放开之后依次编译、烧录和运行。实际测试的过程中可以观察下杜邦线连着的时候测试如何等到杜邦线拔掉的时候测试又是什么样的看看有没有区别。