Hello guys, I am working with STM32G0C1RET6. I want to use STM32 as a USB host and want to save data on USB flash stick. I followed some tutorial from ST microcontroller's youtube channel but I am still not able to mount my USB device. what should I

[jsoda.1]

Here are details about my project:

• I have connected my USB_DM and USB_DP pin directly to USB connector.
• I enable A9 and selected as a GPIO output using VBUS setting in CUBEIDE. Which is providing me 3.3V
• I read that there is inbuilt pull up resistor in STM32G0C1RET6. So, I connected USB connector directly to pins
• I used "f_mount" function to mount my usb device.

My USB device is using FAT32 format. I AM SORRY if I made some dumb mistake; I am newbie

[Muhammed Güler]

If your USB connection is as above, I recommend that you find the MX_DriverVbusFS function in the usbh_platform.c file and make its content compatible with your power switch IC.

https://www.st.com/resource/en/application_note/dm00296349-usb-hardware-and-pcb-guidelines-using-stm32-mcus-stmicroelectronics.pdf

[jsoda.1]

Hiii, thank you so much for suggestion. Is it necessary to set USB connection as you showed in image??

​

I​ didn't make any connection like that. I just connected USB connector pin to STM32's A9 pin.

[Javier1]

A couple of times I accidentaly swapped USB DATA+ and DATA- Lines, double check you didnt do the same.

https://www.youtube.com/watch?v=vwlXUOY7KY0&list=PLnMKNibPkDnFFRBVD206EfnnHhQZI4Hxa&index=7&ab_channel=STMicroelectronics

[Javier1]

Leave a link to the youtube tutorial youre trying to follow and maybe some pictures of your hardware

[jsoda.1]

Hi, thank you so much for reply. No, I made sure that I don't interchange DP and DM lines. Both connections are correct..Here is link of the video I am following:

https://www.youtube.com/watch?v=dC0d8CVEPrQ&list=PLnMKNibPkDnFFRBVD206EfnnHhQZI4Hxa&index=20

Sorry but I can't get picture of hardware. Do I need to use "Current limiter power switch"??

When I run program FRESULT shows FR_DISK_ERR. what does that mean?

[Tesla DeLorean]

>>When I run program FRESULT shows FR_DISK_ERR. what does that mean?

Means your DISKIO layer isn't working, fix that first.

[Muhammed Güler]

You can use STMPS2141 as switch. I also recommend adding a protection element such as USBLC6-2SC6 to the USB data line.​

[jsoda.1]

@Community member​ @Javier Muñoz​ 

Sorry for bothering you guys again. I have tried to solve DISKIO error but everything is working fine. There are no errors. Can low heap size cause FR_DISK_ERR??

I am posting the code I wrote in "USB_host.c" and my settings which I am using:

/* USER CODE END Header */
 
/* Includes ------------------------------------------------------------------*/
 
#include "usb_host.h"
#include "usbh_core.h"
#include "usbh_msc.h"
 
/* USER CODE BEGIN Includes */
#include "ff.h"
/* USER CODE END Includes */
 
/* USER CODE BEGIN PV */
/* Private variables ----------------------------
 * -----------------------------*/
FATFS USBH_fatfs;
FIL MyFile;
FRESULT res;
uint8_t oktext = "USB mounted !";
uint8_t text = "USB not mounted !";
extern char USBHpath[];
extern UART_HandleTypeDef huart3;
/* USER CODE END PV */
 
/* USER CODE BEGIN PFP */
/* Private function prototypes -----------------------------------------------*/
 
/* USER CODE END PFP */
 
/* USB Host core handle declaration */
USBH_HandleTypeDef hUsbHostFS;
ApplicationTypeDef Appli_state = APPLICATION_IDLE;
 
/*
 * -- Insert your variables declaration here --
 */
/* USER CODE BEGIN 0 */
void UserPr(void)
{
 if(f_mount(&USBH_fatfs, USBHpath, 1) != FR_OK)
 {
 	HAL_UART_Transmit(&huart3, text, sizeof(text), 100);
 }
 else
 {
 	HAL_UART_Transmit(&huart3, oktext, sizeof(oktext), 100);
 }
}
/* USER CODE END 0 */

[Tesla DeLorean]

>>Can low heap size cause FR_DISK_ERR??

Generally speaking GNU/GCC hides a lot of potential size issues with heap/stack

Some of the USB Driver Stack for devices used the heap.

FATFS can use the heap for things like long filenames, etc, check ff_conf.h

It can also use the stack for auto/local variables, I'd typical look for at least 1 or 2 KB

Suggest the following syntax for the output

uint8_t text[] = "USB not mounted !";

HAL_UART_Transmit(&huart3, text, sizeof(text)-1, 100); // or strlen(text)