Hi,
From RM0090 (Rev 19 - February 2021), page 1393:
"Host enumeration
The application issues an USB reset (single-ended zero) via the USB by keeping the port
reset bit set in the Host port control and status register (PRST bit in OTG_HS_HPRT) for a
minimum of 10 ms and a maximum of 20 ms. The application monitors the time and then
clears the port reset bit."
But apparently the time in the software is 100ms (FW_F4 1.27.1):
stm32f4xx_ll_usb.c
/**
* @brief USB_OTG_ResetPort : Reset Host Port
* USBx Selected device
* @retval HAL status
* @note (1)The application must wait at least 10 ms
* before clearing the reset bit.
*/
HAL_StatusTypeDef USB_ResetPort(USB_OTG_GlobalTypeDef *USBx)
{
uint32_t USBx_BASE = (uint32_t)USBx;
__IO uint32_t hprt0 = 0U;
hprt0 = USBx_HPRT0;
hprt0 &= ~(USB_OTG_HPRT_PENA | USB_OTG_HPRT_PCDET |
USB_OTG_HPRT_PENCHNG | USB_OTG_HPRT_POCCHNG);
USBx_HPRT0 = (USB_OTG_HPRT_PRST | hprt0);
HAL_Delay(100U); /* See Note #1 */
USBx_HPRT0 = ((~USB_OTG_HPRT_PRST) & hprt0);
HAL_Delay(10U);
return HAL_OK;
}
stm32f4xx_hal_hcd.c:
/**
* @brief Reset the host port.
* hhcd HCD handle
* @retval HAL status
*/
HAL_StatusTypeDef HAL_HCD_ResetPort(HCD_HandleTypeDef *hhcd)
{
return (USB_ResetPort(hhcd->Instance));
}
usbh_conf.c:
/**
* @brief Reset the Host port of the low level driver.
* phost: Host handle
* @retval USBH status
*/
USBH_StatusTypeDef USBH_LL_ResetPort(USBH_HandleTypeDef *phost)
{
HAL_StatusTypeDef hal_status = HAL_OK;
USBH_StatusTypeDef usb_status = USBH_OK;
hal_status = HAL_HCD_ResetPort(phost->pData);
usb_status = USBH_Get_USB_Status(hal_status);
return usb_status;
}
usbh_core.c:
/**
* @brief USBH_Process
* Background process of the USB Core.
* phost: Host Handle
* @retval USBH Status
*/
USBH_StatusTypeDef USBH_Process(USBH_HandleTypeDef *phost)
{
__IO USBH_StatusTypeDef status = USBH_FAIL;
uint8_t idx = 0U;
/* check for Host pending port disconnect event */
if (phost->device.is_disconnected == 1U)
{
phost->gState = HOST_DEV_DISCONNECTED;
}
switch (phost->gState)
{
case HOST_IDLE :
if ((phost->device.is_connected) != 0U)
{
USBH_UsrLog("USB Device Connected");
/* Wait for 200 ms after connection */
phost->gState = HOST_DEV_WAIT_FOR_ATTACHMENT;
USBH_Delay(200U);
(void)USBH_LL_ResetPort(phost);
stm32f4xx_hal.c:
/**
* @brief This function provides minimum delay (in milliseconds) based
* on variable incremented.
* @note In the default implementation , SysTick timer is the source of time base.
* It is used to generate interrupts at regular time intervals where uwTick
* is incremented.
* @note This function is declared as __weak to be overwritten in case of other
* implementations in user file.
* Delay specifies the delay time length, in milliseconds.
* @retval None
*/
__weak void HAL_Delay(uint32_t Delay)
{
uint32_t tickstart = HAL_GetTick();
uint32_t wait = Delay;
/* Add a freq to guarantee minimum wait */
if (wait < HAL_MAX_DELAY)
{
wait += (uint32_t)(uwTickFreq);
}
while((HAL_GetTick() - tickstart) < wait)
{
}
}
STM32H7 (FW_H7 1.11.0)
stm32h7xx_ll_usb.c
/**
* @brief USB_OTG_ResetPort : Reset Host Port
* USBx Selected device
* @retval HAL status
* @note (1)The application must wait at least 10 ms
* before clearing the reset bit.
*/
HAL_StatusTypeDef USB_ResetPort(USB_OTG_GlobalTypeDef *USBx)
{
uint32_t USBx_BASE = (uint32_t)USBx;
__IO uint32_t hprt0 = 0U;
hprt0 = USBx_HPRT0;
hprt0 &= ~(USB_OTG_HPRT_PENA | USB_OTG_HPRT_PCDET |
USB_OTG_HPRT_PENCHNG | USB_OTG_HPRT_POCCHNG);
USBx_HPRT0 = (USB_OTG_HPRT_PRST | hprt0);
HAL_Delay(100U); /* See Note #1 */
USBx_HPRT0 = ((~USB_OTG_HPRT_PRST) & hprt0);
HAL_Delay(10U);
return HAL_OK;
}
