ESP32 Forum

Code: Select all

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include "esp_log.h"
#include "driver/uart.h"
#include "driver/gpio.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#define BUFFER_SIZE 256

#define UART_NUM UART_NUM_1  // Use UART1 for communication
#define TXD_PIN GPIO_NUM_4   // TX pin for UART1 (change as needed)
#define RXD_PIN GPIO_NUM_5   // RX pin for UART1 (change as needed)
#define BAUD_RATE 9600       // Baud rate (match with TTL device)
#define RS485_ENABLE_PIN GPIO_NUM_2  // RS485 Enable (Connect to DE & RE)

uint8_t rxBuff_from_device[32];
uint8_t send_rs485_bytes[32];

// Function prototypes
void process_rs485_data(uint8_t *DeviceRxBuff, int len);

// Function to initialize UART
void init_uart() {
    uart_config_t uart_config = {
        .baud_rate = BAUD_RATE,
        .data_bits = UART_DATA_8_BITS,
        .parity = UART_PARITY_DISABLE,
        .stop_bits = UART_STOP_BITS_1,
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE
    };

    // Install UART driver with TX and RX buffer
    uart_driver_install(UART_NUM, 256, 256, 0, NULL, 0);
    uart_param_config(UART_NUM, &uart_config);
    uart_set_pin(UART_NUM, TXD_PIN, RXD_PIN, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);

    gpio_set_direction(RS485_ENABLE_PIN, GPIO_MODE_OUTPUT);

    // Set default state for RS485 (RX mode)
    gpio_set_level(RS485_ENABLE_PIN, 1);

}



void get_data_from_device(void *pvParameters) {
    while (1) {
        int len = uart_read_bytes(UART_NUM, rxBuff_from_device, sizeof(rxBuff_from_device), 1000 / portTICK_PERIOD_MS);

        if (len > 0) {
             printf("Response : ");
             for (int k = 0; k < len; k++) {
                 printf("%02X ", rxBuff_from_device[k]);
             }
             printf("\n");
            memset(rxBuff_from_device, 0, sizeof(rxBuff_from_device));
        }
    }
}


// Function to send RS485 data to devices
void send_rs485_to_device(uint8_t *data, size_t length) {
    gpio_set_level(RS485_ENABLE_PIN, 1);  // Enable TX mode
   vTaskDelay(10 / portTICK_PERIOD_MS);  // Ensure GPIO switch before sending

    uart_write_bytes(UART_NUM, (const char *)data, length);

    vTaskDelay(30 / portTICK_PERIOD_MS);  // Allow transmission to complete
    gpio_set_level(RS485_ENABLE_PIN, 0);  // Switch back to RX mode

     vTaskDelay(50 / portTICK_PERIOD_MS);  // Allow some time before reading response
}

// Task to send RS485 data every 2 minutes and check response
void periodic_send_task(void *pvParameters) {
    uint8_t buftx[] =  {0x84, 0xBA, 0x20, 0xFF, 0xFE, 0x92, 0x5E, 0x5F, 0x05, 0x01, 0x01, 0x3D, 0x23};  // Example RS485 command
    printf("Sending data...\n");
    send_rs485_to_device(buftx, sizeof(buftx));
    vTaskDelete(NULL);
}

void app_main(void)
{
    // Initialization for RS485
    init_uart();
    xTaskCreate(get_data_from_device, "get_data_from_device", 4096, NULL, 7, NULL);
    xTaskCreate(periodic_send_task, "periodic_send_task", 4096, NULL, 4, NULL);
}