What initialises the contents of the STM32's USB BTABLE when the __HAL_RCC_USB_CLK_ENABLE() macro is executed in HAL_PCD_MspInit()?
问题 I have used STM32CubeMX/IDE to generate a USB HID project for the STM32F3DISCOVERY board. The USB BTABLE register is zero, indicating that the BTABLE is at the start of the Packet Memory Area. (I zero the whole PMA at program start, to avoid stale values.) Just before the execution of the __HAL_RCC_USB_CLK_ENABLE macro (in HAL_PCD_MspInit() in usbd_conf.c ) the values of the BTABLE (at index zero onwards, in the PMA are: After that macro is executed, the values are: The macro expands to: do {