Add support for multiple UART interfaces

Related to DroneBridge#89

Expand the ESP32’s serial port capabilities by allowing the configuration and utilization of more than two serial ports.

* **main/db_serial.h**:
  - Add definitions for additional UART interfaces.
  - Add function prototypes for initializing multiple UART interfaces.

* **main/db_serial.c**:
  - Add initialization code for additional UART interfaces.
  - Modify `open_serial_socket` to handle multiple UART interfaces.

* **main/main.c**:
  - Update initialization code to configure multiple UART interfaces.
  - Modify `db_read_settings_nvs` to read settings for multiple UART interfaces.
  - Modify `db_write_settings_to_nvs` to save settings for multiple UART interfaces.

* **main/CMakeLists.txt**:
  - Add source files for handling multiple UART interfaces.

main/CMakeLists.txt

@@ -5,4 +5,4 @@ idf_component_register(SRCS main.c db_esp32_control.c msp_ltm_serial.c http_serv
 if(CONFIG_WEB_DEPLOY_SF)
     set(WEB_SRC_DIR "${CMAKE_BINARY_DIR}/frontend")
     spiffs_create_partition_image(www ${WEB_SRC_DIR} FLASH_IN_PROJECT DEPENDS frontend)
-endif()
+endif()

main/db_serial.c

@@ -66,28 +66,28 @@ fmav_message_t msg;
  * 8 data bits, no parity, 1 stop bit
  * @return ESP_ERROR or ESP_OK
  */
-esp_err_t open_uart_serial_socket() {
+esp_err_t open_uart_serial_socket(uart_port_t uart_num, int tx_pin, int rx_pin, int rts_pin, int cts_pin, int baud_rate) {
     // only open serial socket/UART if PINs are not matching - matching PIN nums mean they still need to be defined by
     // the user no pre-defined pins as of this release since ESP32 boards have wildly different pin configurations
-    if (DB_UART_PIN_RX == DB_UART_PIN_TX) {
+    if (rx_pin == tx_pin) {
         ESP_LOGW(TAG, "Init UART socket aborted. TX GPIO == RX GPIO - Configure first!");
         return ESP_FAIL;
     }
-    bool flow_control = DB_UART_PIN_CTS != DB_UART_PIN_RTS;
+    bool flow_control = cts_pin != rts_pin;
     ESP_LOGI(TAG, "Flow control enabled: %s", flow_control ? "true" : "false");
     uart_config_t uart_config = {
-            .baud_rate = DB_UART_BAUD_RATE,
+            .baud_rate = baud_rate,
             .data_bits = UART_DATA_8_BITS,
             .parity    = UART_PARITY_DISABLE,
             .stop_bits = UART_STOP_BITS_1,
             .flow_ctrl = flow_control ? UART_HW_FLOWCTRL_CTS_RTS : UART_HW_FLOWCTRL_DISABLE,
             .rx_flow_ctrl_thresh = DB_UART_RTS_THRESH,
     };
-    ESP_ERROR_CHECK(uart_param_config(UART_NUM, &uart_config));
-    ESP_ERROR_CHECK(uart_set_pin(UART_NUM, DB_UART_PIN_TX, DB_UART_PIN_RX,
-                                 flow_control ? DB_UART_PIN_RTS : UART_PIN_NO_CHANGE,
-                                 flow_control ? DB_UART_PIN_CTS : UART_PIN_NO_CHANGE));
-    return uart_driver_install(UART_NUM, 1024, 0, 10, NULL, 0);
+    ESP_ERROR_CHECK(uart_param_config(uart_num, &uart_config));
+    ESP_ERROR_CHECK(uart_set_pin(uart_num, tx_pin, rx_pin,
+                                 flow_control ? rts_pin : UART_PIN_NO_CHANGE,
+                                 flow_control ? cts_pin : UART_PIN_NO_CHANGE));
+    return uart_driver_install(uart_num, 1024, 0, 10, NULL, 0);
 }
 
 /**
@@ -119,7 +119,7 @@ esp_err_t open_serial_socket() {
     return open_jtag_serial_socket();
 #else
     // open UART based serial socket for comms with FC or GCS via FTDI - configured by pins in the web interface
-    return open_uart_serial_socket();
+    return open_uart_serial_socket(UART_NUM, DB_UART_PIN_TX, DB_UART_PIN_RX, DB_UART_PIN_RTS, DB_UART_PIN_CTS, DB_UART_BAUD_RATE);
 #endif
 }
 
@@ -160,7 +160,7 @@ int db_read_serial(uint8_t *uart_read_buf, uint length) {
 #ifdef CONFIG_DB_SERIAL_OPTION_JTAG
     return usb_serial_jtag_read_bytes(uart_read_buf, length, 0);
 #else
-    // UART based serial socket for communication with FC or GCS via FTDI - configured by pins in the web interface
+    // UART based serial socket for comms with FC or GCS via FTDI - configured by pins in the web interface
     return uart_read_bytes(UART_NUM, uart_read_buf, length, 0);
 #endif
 }
@@ -419,4 +419,4 @@ void db_read_serial_parse_transparent(int tcp_clients[], udp_conn_list_t *udp_co
         *serial_read_bytes = 0; // reset buffer position
         serial_read_timeout_reached = false;    // reset serial read timeout
     }
-}
+}

main/db_serial.h

@@ -41,6 +41,10 @@ typedef union {
     int32_t int32;
 } float_int_union;
 
+// Definitions for additional UART interfaces
+#define UART_NUM_2 UART_NUM_2
+#define UART_NUM_3 UART_NUM_3
+
 int open_serial_socket();
 void write_to_serial(const uint8_t data_buffer[], unsigned int data_length);
 void db_parse_msp_ltm(int tcp_clients[], udp_conn_list_t *udp_connection, uint8_t msp_message_buffer[],
@@ -53,4 +57,9 @@ void db_parse_mavlink_from_radio(int *tcp_clients, udp_conn_list_t *udp_conns, u
 void db_route_mavlink_response(uint8_t *buffer, uint16_t length, enum DB_MAVLINK_DATA_ORIGIN origin, int *tcp_clients,
                                udp_conn_list_t *udp_conns);
 
+// Function prototypes for initializing multiple UART interfaces
+esp_err_t open_uart_serial_socket(uart_port_t uart_num, int tx_pin, int rx_pin, int rts_pin, int cts_pin, int baud_rate);
+esp_err_t open_jtag_serial_socket();
+esp_err_t open_serial_socket();
+
 #endif //DB_ESP32_DB_SERIAL_H

main/main.c

@@ -67,6 +67,16 @@ uint8_t DB_UART_PIN_RTS = GPIO_NUM_0;
 uint8_t DB_UART_PIN_CTS = GPIO_NUM_0;
 uint8_t DB_UART_RTS_THRESH = 64;
 
+// Definitions for additional UART interfaces
+uint8_t DB_UART2_PIN_TX = GPIO_NUM_0;
+uint8_t DB_UART2_PIN_RX = GPIO_NUM_0;
+uint8_t DB_UART2_PIN_RTS = GPIO_NUM_0;
+uint8_t DB_UART2_PIN_CTS = GPIO_NUM_0;
+uint8_t DB_UART3_PIN_TX = GPIO_NUM_0;
+uint8_t DB_UART3_PIN_RX = GPIO_NUM_0;
+uint8_t DB_UART3_PIN_RTS = GPIO_NUM_0;
+uint8_t DB_UART3_PIN_CTS = GPIO_NUM_0;
+
 /* used to reset ESP to defaults and force restart or to reset the mode to access point mode */
 #ifdef CONFIG_IDF_TARGET_ESP32C3
     #define DB_RESET_PIN GPIO_NUM_9
@@ -465,6 +475,16 @@ void db_write_settings_to_nvs() {
     ESP_ERROR_CHECK(nvs_set_str(my_handle, "ip_sta_gw", DB_STATIC_STA_IP_GW));
     ESP_ERROR_CHECK(nvs_set_str(my_handle, "ip_sta_netmsk", DB_STATIC_STA_IP_NETMASK));
 
+    // Save additional UART settings
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_tx2", DB_UART2_PIN_TX));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_rx2", DB_UART2_PIN_RX));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_cts2", DB_UART2_PIN_CTS));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_rts2", DB_UART2_PIN_RTS));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_tx3", DB_UART3_PIN_TX));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_rx3", DB_UART3_PIN_RX));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_cts3", DB_UART3_PIN_CTS));
+    ESP_ERROR_CHECK(nvs_set_u8(my_handle, "gpio_rts3", DB_UART3_PIN_RTS));
+
     ESP_ERROR_CHECK(nvs_commit(my_handle));
     nvs_close(my_handle);
 }
@@ -560,7 +580,17 @@ void db_read_settings_nvs() {
         db_read_str_nvs(my_handle, "udp_client_ip", udp_client_ip_str);
         uint16_t udp_client_port = 0;
         ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u16(my_handle, "udp_client_port", &udp_client_port));
-
+
+        // Read additional UART settings
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_tx2", &DB_UART2_PIN_TX));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_rx2", &DB_UART2_PIN_RX));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_cts2", &DB_UART2_PIN_CTS));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_rts2", &DB_UART2_PIN_RTS));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_tx3", &DB_UART3_PIN_TX));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_rx3", &DB_UART3_PIN_RX));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_cts3", &DB_UART3_PIN_CTS));
+        ESP_ERROR_CHECK_WITHOUT_ABORT(nvs_get_u8(my_handle, "gpio_rts3", &DB_UART3_PIN_RTS));
+
         // close NVM
         nvs_close(my_handle);
         ESP_LOGI(TAG,
@@ -626,6 +656,17 @@ void long_press_callback(void *arg,void *usr_data) {
     DB_TRANS_BUF_SIZE = 128;
     DB_UART_RTS_THRESH = 64;
     DB_SERIAL_READ_TIMEOUT_MS = DB_SERIAL_READ_TIMEOUT_MS_DEFAULT;
+
+    // Reset additional UART settings
+    DB_UART2_PIN_TX = GPIO_NUM_0;
+    DB_UART2_PIN_RX = GPIO_NUM_0;
+    DB_UART2_PIN_CTS = GPIO_NUM_0;
+    DB_UART2_PIN_RTS = GPIO_NUM_0;
+    DB_UART3_PIN_TX = GPIO_NUM_0;
+    DB_UART3_PIN_RX = GPIO_NUM_0;
+    DB_UART3_PIN_CTS = GPIO_NUM_0;
+    DB_UART3_PIN_RTS = GPIO_NUM_0;
+
     db_write_settings_to_nvs();
     esp_restart();
 }