ESP32 Forum

Posted: **Tue Jan 17, 2023 7:10 pm**

Hi everyone,

I have an issue about uart communication. I have two esp32 these are esp32-devkit-c_v4(esp32-wroom-32d) and ESP32-DevKitS-V1(esp32-s3-wroom-1).

I want to send data from esp32-wroom-32d(uart0) to esp32-s3(uart1) via uart but i can't it.

I can't read data with uart1 as follow but when i use uart0 it is working.
How can i use uart1 for reading data.

Thanks,

[Pins]
esp32-wroom-32d --> esp32-s3
Tx(pin_uart0_tx) ------------- Rx(pin_uart1_rx_gpio_18)
Rx(pin_uart0_rx) ------------- Tx(pin_uart1_tx_gpio_17)

::Codes::
::ESP32-WROOM-32D::

Code: [Select all] [Expand/Collapse]

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "driver/uart.h"
 
#include "freertos/freeRTOS.h"
#include "freertos/task.h"
 
void app_main(void)
{
    printf("Started ... \n");
 
    int bufferSize = 250;
    uart_port_t port = UART_NUM_0;
    QueueHandle_t queue;
 
    uart_config_t uartConfig = {
        .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(port, &uartConfig);
    uart_driver_install(port, bufferSize, bufferSize, 10, &queue, 0);
 
    //TX - RX - RTS - CTS
    uart_set_pin(port, 1, 3, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
 
    
    
    while(true){
        
        char *t = "Test message!\n";
        uart_write_bytes(port, t, strlen(t));
 
        vTaskDelay(pdMS_TO_TICKS(5000));
    }
    
}

GeSHi © Codebox Plus Extension

::ESP32-S3::

Code: [Select all] [Expand/Collapse]

#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/uart.h"
 
 
static void echo_task(void *arg)
{
 
    int bufferSize = 250;
    uart_port_t port = UART_NUM_1;
    QueueHandle_t queue;
 
    uart_config_t uartConfig = {
        .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(port, &uartConfig);
 
    //TX - RX - RTS - CTS
    uart_set_pin(port, 17, 18, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
 
    uart_driver_install(port, bufferSize-1, bufferSize, 10, &queue, 0);
 
 
    // Configure a temporary buffer for the incoming data
    uint8_t *data = (uint8_t *) malloc(bufferSize);
 
    while (1) {
        // Read data from the UART
 
        size_t len = 0;
        uart_get_buffered_data_len(port, &len);
 
        uart_read_bytes(port, data, 1024, pdMS_TO_TICKS(1000));
        printf("%d\n",len);
        if(len > 0){
            printf("%s\n", (char*)data);
        }
 
        vTaskDelay(pdMS_TO_TICKS(3000));
    }
}
 
void app_main(void)
{
    printf("Started... \n");
 
    xTaskCreate(echo_task, "uart_echo_task", 4096, NULL, 10, NULL);
}

Posted: **Thu Jan 19, 2023 8:30 am**

Could you do not use UART0 to communicate, it is connected to a serial chip, then serial chip may affect the communication.
You could try to 1) use anther GPIO pair as UART 2) replace UART0 series resistor ( 0 ohm ) with 500 ~ 1K.

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