example: add nmea0183 parser example

Add NMEA0183 Parser example to illustrate how to use uart event driver together with esp event library to get GPS information.

examples/peripherals/uart/uart_echo/main/CMakeLists.txt

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+set(COMPONENT_SRCS "uart_echo_example_main.c")
+set(COMPONENT_ADD_INCLUDEDIRS ".")
+
+register_component()

examples/peripherals/uart/uart_echo/main/component.mk

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

examples/peripherals/uart/uart_echo/main/uart_echo_example_main.c

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+/* UART Echo Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+#include <stdio.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "driver/uart.h"
+
+/**
+ * This is an example which echos any data it receives on UART1 back to the sender,
+ * with hardware flow control turned off. It does not use UART driver event queue.
+ *
+ * - Port: UART1
+ * - Receive (Rx) buffer: on
+ * - Transmit (Tx) buffer: off
+ * - Flow control: off
+ * - Event queue: off
+ * - Pin assignment: see defines below
+ */
+
+#define ECHO_TEST_TXD  (GPIO_NUM_4)
+#define ECHO_TEST_RXD  (GPIO_NUM_5)
+#define ECHO_TEST_RTS  (UART_PIN_NO_CHANGE)
+#define ECHO_TEST_CTS  (UART_PIN_NO_CHANGE)
+
+#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 = 115200,
+        .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_1, &uart_config);
+    uart_set_pin(UART_NUM_1, ECHO_TEST_TXD, ECHO_TEST_RXD, ECHO_TEST_RTS, ECHO_TEST_CTS);
+    uart_driver_install(UART_NUM_1, BUF_SIZE * 2, 0, 0, NULL, 0);
+
+    // 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_1, data, BUF_SIZE, 20 / portTICK_RATE_MS);
+        // Write data back to the UART
+        uart_write_bytes(UART_NUM_1, (const char *) data, len);
+    }
+}
+
+void app_main()
+{
+    xTaskCreate(echo_task, "uart_echo_task", 1024, NULL, 10, NULL);
+}