Uso de USB como salida serie en modo VCP (Virtual Comm Port) en la plataforma STM32F429I Discovery

• Configuración pines SYS para depuración (pines SWD) y GPIO para Leds

• Configuración pines RCC para reloj HSE

• Configuración pines USB_OTG_HS como Device utilizando PHY FS

• Configuración MiddleWare para USB de tipo CDC modo VCP

• Configuración de relojes adecuados (USB = 48 MHz, SYS = 168 MHz)

• Configuración GPIO

• Configuración parámetros USB OTG HS

* Configuración pines USB OTG HS

* Configuración NVIC

Simplemente se ha incluido el archivo usbd_cdc_if.h:

   #include "usbd_cdc_if.h"

para hacer uso de la función de transmisión VCP CDC_Transmit_HS:

   CDC_Transmit_HS((uint8_t*)tx_string, strlen(tx_string));

y enviar el número de iteración del bucle infinito donde se alterna el encendido de los Leds cada segundo haciendo uso de las funciones básicas GPIO HAL_GPIO_WritePin y de retraso en milisegundos HAL_Delay:

   HAL_GPIO_WritePin(GPIOG, GPIO_PIN_14, GPIO_PIN_SET);
   HAL_GPIO_WritePin(GPIOG, GPIO_PIN_13, GPIO_PIN_RESET);
   HAL_Delay(500);

usb_vcp.c

/**
  ******************************************************************************
  * File Name          : main.c
  * Description        : Main program body
  ******************************************************************************
  *
  * COPYRIGHT(c) 2016 STMicroelectronics
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  */
/* Includes ------------------------------------------------------------------*/
#include "stm32f4xx_hal.h"
#include "usb_device.h"
#include "usbd_cdc_if.h"
#include "gpio.h"
 
/* USER CODE BEGIN Includes */
 
/* USER CODE END Includes */
 
/* Private variables ---------------------------------------------------------*/
 
/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
 
/* USER CODE END PV */
 
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
 
/* USER CODE BEGIN PFP */
/* Private function prototypes -----------------------------------------------*/
 
/* USER CODE END PFP */
 
/* USER CODE BEGIN 0 */
 
/* USER CODE END 0 */
 
int main(void)
{
 
  /* USER CODE BEGIN 1 */
 
  /* USER CODE END 1 */
 
  /* MCU Configuration----------------------------------------------------------*/
 
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USB_DEVICE_Init();
 
  /* USER CODE BEGIN 2 */
  int i = 0;
//char *rx_char;
  char tx_string[80];
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
  /* USER CODE END WHILE */
      //leds
      HAL_GPIO_WritePin(GPIOG, GPIO_PIN_14, GPIO_PIN_SET);
      HAL_GPIO_WritePin(GPIOG, GPIO_PIN_13, GPIO_PIN_RESET);
      HAL_Delay(500);
      HAL_GPIO_WritePin(GPIOG, GPIO_PIN_14, GPIO_PIN_RESET);
      HAL_GPIO_WritePin(GPIOG, GPIO_PIN_13, GPIO_PIN_SET);
      HAL_Delay(500);
      //usb hs vcp
//      if (CDC_Receive_HS((uint8_t*)&rx_char,(uint32_t*)1) == USBD_OK) {
//          sprintf(tx_string, "Loop: %d, Ping: %c\n\r", i  , *rx_char);
//      } else {
      sprintf(tx_string, "Loop: %d\n\r", i  );
//      }
      CDC_Transmit_HS((uint8_t*)tx_string, strlen(tx_string));
  /* USER CODE BEGIN 3 */
 
  }
  /* USER CODE END 3 */
 
}
 
/** System Clock Configuration
*/
void SystemClock_Config(void)
{
 
  RCC_OscInitTypeDef RCC_OscInitStruct;
  RCC_ClkInitTypeDef RCC_ClkInitStruct;
 
  __PWR_CLK_ENABLE();
 
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
 
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 4;
  RCC_OscInitStruct.PLL.PLLN = 168;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  HAL_RCC_OscConfig(&RCC_OscInitStruct);
 
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);
 
  HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
 
  HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
 
  /* SysTick_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}
 
/* USER CODE BEGIN 4 */
 
/* USER CODE END 4 */
 
#ifdef USE_FULL_ASSERT
 
/**
   * @brief Reports the name of the source file and the source line number
   * where the assert_param error has occurred.
   * @param file: pointer to the source file name
   * @param line: assert_param error line source number
   * @retval None
   */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
    ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
 
}
 
#endif
 
/**
  * @}
  */
 
/**
  * @}
*/
 
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

Una vez programada la flash del dispositivo comprobaremos la existencia de la nueva conexión USB a nuestro sistema mediante el comando lsusb y detectaremos el dispositivo al que vamos a conectarnos en modo serie VCP mediante el comando dmesg:

$ lsusb
Bus 005 Device 004: ID 0483:3748 STMicroelectronics ST-LINK/V2
Bus 005 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 017: ID 0483:5740 STMicroelectronics STM32F407

$ dmesg
.....
[82338.963047] usb 3-1: New USB device found, idVendor=0483, idProduct=5740
[82338.963054] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[82338.963058] usb 3-1: Product: STM32 Virtual ComPort
[82338.963062] usb 3-1: Manufacturer: STMicroelectronics
[82338.963065] usb 3-1: SerialNumber: 00000000001A
[82338.967143] cdc_acm 3-1:1.0: This device cannot do calls on its own. It is not a modem.
[82338.967182] cdc_acm 3-1:1.0: ttyACM0: USB ACM device

En este paso corresponde al dispositivo mapeado en ''/dev/ttyACM0''  al que podemos conectar mediante un programa de terminal, como //minicom//  o //putty//  y obtendremos una salida similar a esta: {{:pub:usb_acm_putty.png?500}}\\