USB host or usb cdc or UART

sana1 · ‎2024-05-06

In my graduation project, I'm utilizing the STM32H735_DK microcontroller to communicate with a GMSL (Generalized Memory Scalable Logic) device. Typically, these devices are configured using terminal programs like Putty or TeraTerm. Commands, such as "PICT START," are sent via a USB A to USB B cable from a PC to the GMSL.

Despite my attempts to replicate this communication using UART and USB CDC with the STM32, I've encountered difficulties. Conversely, my friend successfully communicated with a GMSL device using a Raspberry Pi via a serial port.

I'm unsure how to resolve these issues and would appreciate any assistance. Thank you!

Andrew Neil · ‎2024-05-08

@sana1 wrote:
I have gathered information from the schematic of the GMSL UART connection to an MCU (Micro 100). .

So why don't you just copy that, and use the STM32 in place of the "Micro 100"

Then you have a simple UART connection from the STM32 to the "GMSL" (still no idea what that is).

@sana1 wrote:
My question is about configuring the USB on the STM32. .

Your question doesn't seem to be really about the STM32, but a fundamental lack of understanding of how USB works.

Therefore I would strongly suggest that you don't use USB, and just use a simple UART connection instead.

@sana1 wrote:
Should I set it up as a USB CDC device or host ... I'm new to working with STM .

This has nothing specifically to do with STM32.

Whatever device you use - whether it's a PC or a Raspberry Pi or an STM32 or any other microcontroller - needs to be a USB Host, and that Host will need to implement the CDC.

@sana1 wrote:
I'm new to working with STM and this project marks my first venture into this field. Any guidance would be greatly appreciated.

You should be seeking guidance from your teacher/supervisor/tutor. It sounds like your project may be a bit beyond you - you really should be discussing with your teacher/supervisor/tutor whether it's actually an appropriate project for you...

sana1 · ‎2024-05-08

I appreciate your response. My objective is to use the STM32 to send commands instead of relying on a PC connected via USB. From what I understand, I should configure the USB of the STM32 as a host because the GMSL module acts as a USB device, requiring a host for communication to accept commands. The GMSL module is crucial for generating photos or videos for a cluster of

Andrew Neil · ‎2024-05-08

@sana1 wrote:
the GMSL module acts as a USB device,

But that's not what you showed in your schematics!

Your schematics showed an external USB-to-UART converter.

So why not just do away with that converter, and use a simple UART connection direct to the mystery "GMSL" ?

@sana1 wrote:
The GMSL module is crucial for generating photos or videos for a cluster of

Would you care to complete that sentence?

Are you sure that "GMSL" doesn't actually stand for "Gigabit Multimedia Serial Link" ?

:thinking_face:

sana1 · ‎2024-05-08

Unfortunately, I don't have direct access to the UART because all the components are integrated on the PCB.

sana1 · ‎2024-05-08

so i have just access to the usb

Andrew Neil · ‎2024-05-08

So why did you even suggest UART in the first place?

Clearly, then, your only choice is to implement a Host for the FT232 chip.

As your classmate already has this working on a Raspberry Pi, why don't you also use a Raspberry Pi ?

Breakout boards for the FT232RL are widely available; eg,

https://thepihut.com/products/ft232-usb-uart-board-usb-c

It would be wise to start with something like that - so you can test your Host independently of the "GMSL".

sana1 · ‎2024-05-09

Since communication with the GMSL module is integral to the project, I must utilize the STM32, as using a Raspberry Pi is not an option. I've already developed a project using USB HOST functionality. However, I'm encountering an issue where the Appli_state remains in a state of not being ready.

Andrew Neil · ‎2024-05-09

Please use this button to properly post source code:

@sana1 wrote:
I must utilize the STM32, as using a Raspberry Pi is not an option.

So how come your classmate is using a Raspberry Pi?

@sana1 wrote:
I've already developed a project using USB HOST functionality.

Does that work with a standalone FT232RL - eg, on a breakout board or in a cable?

Or with any other USB CDC device?

@sana1 wrote:
the Appli_state remains in a state of not being ready.

So what state is it in?

sana1 · ‎2024-05-09

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_host.h"

/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "usbh_cdc.h"

/* USER CODE END Includes */

/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */

/* USER CODE END PTD */

/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */

/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */

/* USER CODE END PM */

/* Private variables ---------------------------------------------------------*/

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
void MX_USB_HOST_Process(void);

/* USER CODE BEGIN PFP */

/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
extern USBH_HandleTypeDef hUsbHostHS;
extern ApplicationTypeDef Appli_state ;
 USBH_StatusTypeDef usbresult;
#define  RX_BUFF_SIZE 1024

uint8_t CDC_RX_Buffer[RX_BUFF_SIZE];
uint8_t CDC_TX_Buffer[RX_BUFF_SIZE];
typedef enum{
	CDC_STATE_IDLE=0,
	CDC_SEND,
	CDC_RECEIVE,
}CDC_StateTypedef;

CDC_StateTypedef CDC_STATE=CDC_STATE_IDLE;

uint8_t i=0;
void CDC_HANDLE(void)
{
	switch (CDC_STATE)
			{
	case CDC_STATE_IDLE:
		{USBH_CDC_Stop(&hUsbHostHS);
	     int len = sprintf((char*)CDC_TX_Buffer ,"pict start 03\n");

	     if(USBH_CDC_Transmit(&hUsbHostHS,CDC_TX_Buffer,len)==USBH_OK)
	     {   HAL_Delay(1000);
	    	 HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_2);
	    	 CDC_STATE=CDC_RECEIVE;
	     }break;
			}
	case CDC_RECEIVE:
	{
		USBH_CDC_Stop(&hUsbHostHS);
		usbresult =USBH_CDC_Receive(&hUsbHostHS,(uint8_t*)CDC_RX_Buffer,RX_BUFF_SIZE);
		HAL_Delay(1000);
		CDC_STATE=CDC_IDLE;

	}
	default:
		break;
			}
}

/* USER CODE END 0 */

/**
  * @brief  The application entry point.
  * @retval int
  */
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();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_USB_HOST_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
    MX_USB_HOST_Process();

    /* USER CODE BEGIN 3 */
    //userfunction();
    if(Appli_state == APPLICATION_READY)
      {
    CDC_HANDLE();


     }
  }
  /* USER CODE END 3 */
}

/**
  * @brief System Clock Configuration
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  /** Supply configuration update enable
  */
  HAL_PWREx_ConfigSupply(PWR_DIRECT_SMPS_SUPPLY);

  /** Configure the main internal regulator output voltage
  */
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE0);

  while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}

  /** Initializes the RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48|RCC_OSCILLATORTYPE_HSE;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 32;
  RCC_OscInitStruct.PLL.PLLN = 129;
  RCC_OscInitStruct.PLL.PLLP = 2;
  RCC_OscInitStruct.PLL.PLLQ = 4;
  RCC_OscInitStruct.PLL.PLLR = 2;
  RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_2;
  RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;
  RCC_OscInitStruct.PLL.PLLFRACN = 0;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /** Initializes the CPU, AHB and APB buses clocks
  */
  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2
                              |RCC_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.AHBCLKDivider = 2;
  RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;
  RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK)
  {
    Error_Handler();
  }
}

/**
  * @brief GPIO Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_GPIO_Init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();
  __HAL_RCC_GPIOH_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();

  /*Configure GPIO pin Output Level */
  HAL_GPIO_WritePin(GPIOH, GPIO_PIN_5, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PH5 */
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOH, &GPIO_InitStruct);

}

/* USER CODE BEGIN 4 */

/* USER CODE END 4 */

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#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 /* USE_FULL_ASSERT */