I am trying to use USB(CDC) without the VBus connection on the STM32H755(Nuclueo-H755ZI-Q).
But I can't.
Please tell me the correct confinglation and procedure
I use ST USB middleware with CDC class.
There is no sample project for STM32H755.
So I ported myself.
It worked.(with VBus)
I changed following points for using without VBus.
comment out following.(main() "main.c")
HAL_PWREx_EnableUSBVoltageDetector();
comment out followings.(void HAL_PCD_MspInit(PCD_HandleTypeDef * hpcd) "usbd_conf.c")
/* Configure VBUS Pin */
GPIO_InitStruct.Pin = GPIO_PIN_9;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
And I checked this.
USBD_StatusTypeDef USBD_LL_Init(USBD_HandleTypeDef * pdev) "usbd_conf.c"
hpcd.Init.vbus_sensing_enable = 0;
~~~
* this value was already "0".
At first, it seemed to work,
But that was wrong.
After running code with VBus enabled, if you debug-execute code with VBus disabled in CubeIDE without powering off, it works. However, it fails to run after powering off.
I have experience running USB without VBus on STM32L4 and STM32F4.
On those models, simply setting
hpcd.Init.vbus_sensing_enable = 0;
made it work.
I think STH32H755 requires other procedure.
Does anyone know about this?
So I believe this is possible.
