refactor(driver): Refactor uart driver for esp8266 idf

examples/peripherals/uart_echo/Makefile

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+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := uart_echo
+
+include $(IDF_PATH)/make/project.mk
+

examples/peripherals/uart_echo/README.md

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+# _UART Echo Example_
+
+_This is an example which echoes any data it receives on UART0 back to the sender._
+
+## How to use example
+
+### Hardware Required
+
+1. Connect an external serial interface to an ESP8266 board. The external interface should have 3.3V outputs. You may use e.g. 3.3V compatible USB-to-serial dongle:  
+
+  | ESP8266 Interface | #define | ESP8266 Pin | External UART Pin |  
+  | --- | --- | --- | --- |  
+  | Transmit Data (TxD) | ECHO_TEST_TXD | GPIO26 | RxD |  
+  | Receive Data (RxD) | ECHO_TEST_RXD | GPIO25 | TxD |  
+  | Ground | n/a | GND | GND |  
+
+2. Verify if echo indeed comes from ESP8266 by disconnecting either 'TxD' or 'RxD' pin. There should be no any echo once any pin is disconnected.
+
+* Using a hardware flow control
+
+  This is an optional check to verify if the hardware flow control works. To set it up you need an external serial interface that has RTS and CTS signals. 
+
+  1. Connect the extra RTS/CTS signals as below  
+
+      | ESP8266 Interface | #define | ESP8266 Pin | External UART Pin |  
+      | --- | --- | --- | --- |  
+      | Request to Send (RTS) | ECHO_TEST_RTS | GPIO13 | CTS |  
+      | Clear to Send (CTS) | ECHO_TEST_CTS | GPIO12 | RTS |  
+  
+  2. Configure UART0 driver to use the hardware flow control by setting `.flow_ctrl = UART_HW_FLOWCTRL_CTS_RTS` and adding `.rx_flow_ctrl_thresh = 122`
+
+### Configure the project
+
+```
+make menuconfig
+```
+
+* Set serial port under Serial Flasher Options.  
+* `make monitor` baud rate set to what you set in the example.
+
+
+### Build and Flash
+
+Build the project and flash it to the board, then run monitor tool to view serial output:
+
+```
+make -j4 flash monitor
+```
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
+
+## Example Output  
+
+```
+I (180) boot: Loaded app from partition at offset 0x10000
+I (0) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
+I (0) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
+0123456789
+```

examples/peripherals/uart_echo/main/component.mk

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+#
+# Main Makefile. This is basically the same as a component makefile.
+#

examples/peripherals/uart_echo/main/uart_echo_example_main.c

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+// Copyright 2018-2025 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+
+#include "driver/uart.h"
+
+/**
+ * This is an example which echos any data it receives on UART0 back to the sender,
+ * with hardware flow control turned off. It does not use UART driver event queue.
+ *
+ * - Port: UART0
+ * - Receive (Rx) buffer: on
+ * - Transmit (Tx) buffer: off
+ * - Flow control: off
+ * - Event queue: off
+ */
+
+#define BUF_SIZE (1024)
+
+static void echo_task()
+{
+    // Configure parameters of an UART driver,
+    // communication pins and install the driver
+    uart_config_t uart_config = {
+        .baud_rate = 74880,
+        .data_bits = UART_DATA_8_BITS,
+        .parity    = UART_PARITY_DISABLE,
+        .stop_bits = UART_STOP_BITS_1,
+        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE
+    };
+    uart_param_config(UART_NUM_0, &uart_config);
+    uart_driver_install(UART_NUM_0, BUF_SIZE * 2, 0, 0, NULL);
+
+    // Configure a temporary buffer for the incoming data
+    uint8_t *data = (uint8_t *) malloc(BUF_SIZE);
+
+    while (1) {
+        // Read data from the UART
+        int len = uart_read_bytes(UART_NUM_0, data, BUF_SIZE, 20 / portTICK_RATE_MS);
+        // Write data back to the UART
+        uart_write_bytes(UART_NUM_0, (const char *) data, len);
+    }
+}
+
+void app_main()
+{
+    xTaskCreate(echo_task, "uart_echo_task", 1024, NULL, 10, NULL);
+}

examples/peripherals/uart_events/Makefile

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+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := uart_events
+
+include $(IDF_PATH)/make/project.mk
+

examples/peripherals/uart_events/README.md

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+# _UART Events Example_  
+
+_This example shows how to use the UART driver to handle special UART events. It also reads data from UART0 directly, and echoes it to console._
+
+* Compile and load example from terminl running `make flash monitor`
+* Being in 'monotor' type samething to see the `UART_DATA` events and the typed data displayed.
+
+## How to use example
+
+### Configure the project
+
+```
+make menuconfig
+```
+
+* Set serial port under Serial Flasher Options.  
+* `make monitor` baud rate set to what you set in the example.
+
+
+### Build and Flash
+
+Build the project and flash it to the board, then run monitor tool to view serial output:
+
+```
+make -j4 flash monitor
+```
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
+
+## Example Output  
+
+* Paste `0123456789` to monitor, the `UART DATA` event will be received.
+
+```
+I (185) boot: Loaded app from partition at offset 0x10000
+I (0) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
+I (0) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
+I (0) uart: queue free spaces: 100
+I (15) uart_events: uart[0] event:
+I (15) uart_events: [UART DATA]: 10
+I (15) uart_events: [DATA EVT]:
+0123456789
+```

examples/peripherals/uart_events/main/component.mk

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+#
+# Main Makefile. This is basically the same as a component makefile.
+#

examples/peripherals/uart_events/main/uart_events_example_main.c

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+// Copyright 2018-2025 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "freertos/queue.h"
+#include "driver/uart.h"
+#include "esp_log.h"
+
+
+static const char *TAG = "uart_events";
+
+/**
+ * This example shows how to use the UART driver to handle special UART events.
+ *
+ * It also reads data from UART0 directly, and echoes it to console.
+ *
+ * - Port: UART0
+ * - Receive (Rx) buffer: on
+ * - Transmit (Tx) buffer: on
+ * - Flow control: off
+ * - Event queue: on
+ * - Pin assignment: TxD (default), RxD (default)
+ */
+
+#define EX_UART_NUM UART_NUM_0
+
+#define BUF_SIZE (1024)
+#define RD_BUF_SIZE (BUF_SIZE)
+static QueueHandle_t uart0_queue;
+
+static void uart_event_task(void *pvParameters)
+{
+    uart_event_t event;
+    size_t buffered_size;
+    uint8_t *dtmp = (uint8_t *) malloc(RD_BUF_SIZE);
+
+    for (;;) {
+        // Waiting for UART event.
+        if (xQueueReceive(uart0_queue, (void *)&event, (portTickType)portMAX_DELAY)) {
+            bzero(dtmp, RD_BUF_SIZE);
+            ESP_LOGI(TAG, "uart[%d] event:", EX_UART_NUM);
+
+            switch (event.type) {
+                // Event of UART receving data
+                // We'd better handler data event fast, there would be much more data events than
+                // other types of events. If we take too much time on data event, the queue might be full.
+                case UART_DATA:
+                    ESP_LOGI(TAG, "[UART DATA]: %d", event.size);
+                    uart_read_bytes(EX_UART_NUM, dtmp, event.size, portMAX_DELAY);
+                    ESP_LOGI(TAG, "[DATA EVT]:");
+                    uart_write_bytes(EX_UART_NUM, (const char *) dtmp, event.size);
+                    break;
+
+                // Event of HW FIFO overflow detected
+                case UART_FIFO_OVF:
+                    ESP_LOGI(TAG, "hw fifo overflow");
+                    // If fifo overflow happened, you should consider adding flow control for your application.
+                    // The ISR has already reset the rx FIFO,
+                    // As an example, we directly flush the rx buffer here in order to read more data.
+                    uart_flush_input(EX_UART_NUM);
+                    xQueueReset(uart0_queue);
+                    break;
+
+                // Event of UART ring buffer full
+                case UART_BUFFER_FULL:
+                    ESP_LOGI(TAG, "ring buffer full");
+                    // If buffer full happened, you should consider encreasing your buffer size
+                    // As an example, we directly flush the rx buffer here in order to read more data.
+                    uart_flush_input(EX_UART_NUM);
+                    xQueueReset(uart0_queue);
+                    break;
+
+                case UART_PARITY_ERR:
+                    ESP_LOGI(TAG, "uart parity error");
+                    break;
+
+                // Event of UART frame error
+                case UART_FRAME_ERR:
+                    ESP_LOGI(TAG, "uart frame error");
+                    break;
+
+                // Others
+                default:
+                    ESP_LOGI(TAG, "uart event type: %d", event.type);
+                    break;
+            }
+        }
+    }
+
+    free(dtmp);
+    dtmp = NULL;
+    vTaskDelete(NULL);
+}
+
+void app_main()
+{
+    // Configure parameters of an UART driver,
+    // communication pins and install the driver
+    uart_config_t uart_config = {
+        .baud_rate = 74880,
+        .data_bits = UART_DATA_8_BITS,
+        .parity = UART_PARITY_DISABLE,
+        .stop_bits = UART_STOP_BITS_1,
+        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE
+    };
+    uart_param_config(EX_UART_NUM, &uart_config);
+
+    // Install UART driver, and get the queue.
+    uart_driver_install(EX_UART_NUM, BUF_SIZE * 2, BUF_SIZE * 2, 100, &uart0_queue);
+
+    // Create a task to handler UART event from ISR
+    xTaskCreate(uart_event_task, "uart_event_task", 2048, NULL, 12, NULL);
+}