I'm working on communicating from esp32-c3-wroom-2 module to MAX chip.
From MAX2 to I'll send one time data to MAX1(Connected to esp module).
Initially I'm sending data from esp to MAX2 side. This is working fine. But after sending data my esp switching to receive mode by making RE&DE to low. So, This one is not working.
Below I have attached my esp source code and connections. Kindly let me know if any modifications required.
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);
}
Initially data send to another device(MAX-2, which contains MAX chip) onetime successfully. And then I switched to Receiver mode by enabling RE/DE to low.
When I try to send data from another device to esp chip, why data not received at esp side ?
I checked response at esp RX gpio by connecting TTL-USB Rx pin and response printing in realterm. Only esp side issue is there.
Connections
ESP MAX-1
VCC VCC
GND GND
TX(GPIO-4) DI
RX(GPIO-5) RO
DE_RE(GPIO-2) DE_RE
MAX-1 MAX-2
VCC VCC
GND GND
A A
B B
