Can the ESP32-C3's USB-CDC port be used like a UART?

[jitenshap]

With the ESP32-Arduino, I learned that we can exchange data with USB-CDC just as we do with a physical UART port,
using the same functions as with a physical UART port, such as Serial.print() and Serial.read().

I also learned that ESP-IDF allows interactive data exchange between the PC and ESP32-C3 using the esp_console component.

However, in order to exchange data in a free format, for example without line feed codes,
I would like to communicate with ESP32-C3+ESP-IDF using USB-CDC in the same way as with a regular UART.

Is there any easy way to Tx/Rx data via USB-CDC using ESP32-C3 + ESP-IDF?

[dongrigorio]

I found it on the website https://blog.csdn.net/ai_ljh/article/details/126999395
It works.

Code: [Select all] [Expand/Collapse]

1. #include <stdio.h>
2. #include "sdkconfig.h"
3. #include "freertos/FreeRTOS.h"
4. #include "freertos/task.h"
5. #include "esp_system.h"
6. #include "esp_spi_flash.h"
7. #include "string.h"
8. #include "hal/usb_serial_jtag_ll.h"
9. void mytask1(void *pvParameter)
10. {
11.     uint8_t *rxbuf;
12.     int cnt;
13.     rxbuf = (uint8_t *)malloc(64);
14.     int rxcnt;
15.  
16.     while (1)
17.     {
18.         if (usb_serial_jtag_ll_rxfifo_data_available())
19.         {
20.             rxcnt = usb_serial_jtag_ll_read_rxfifo(rxbuf,64);
21.             cnt = (int)usb_serial_jtag_ll_write_txfifo((const uint8_t *)rxbuf, rxcnt);
22.             usb_serial_jtag_ll_txfifo_flush();
23.             //printf("Send %d characters to host \n", cnt);
24.         }
25.         vTaskDelay(pdMS_TO_TICKS(10));
26.     }
27.     free(rxbuf);
28.     vTaskDelete(NULL);
29. }
30.  
31. void app_main(void)
32. {
33.     xTaskCreate(mytask1, "mytask1", 1024 * 5, NULL, 1, NULL);
34. }

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[dentra]

Hi,

the datasheet say:

Code: Select all

USB - GPIO18 and GPIO19 are USB pins. The pull-up value of a USB pin is controlled by the pin’s pull-up
value together with USB pull-up value. If any of the two pull-up values is 1, the pin’s pull-up resistor will be
enabled. The pull-up resistors of USB pins are controlled by USB_SERIAL_JTAG_DP_PULLUP bit.

so, try to clear USB_SERIAL_JTAG_DP_PULLUP bit and then just use standard uart functions (uart_param_config, uart_set_pin, uart_driver_install, uart_write_bytes, uart_read_bytes, etc)

Code: Select all

CLEAR_PERI_REG_MASK(USB_SERIAL_JTAG_CONF0_REG, USB_SERIAL_JTAG_DP_PULLUP);