How to determine Rx event of USB CDC ACM

[DK3]

Hi,

I use STM32U575.

The STM32U575 works as a USB CDC ACM device and I implemented it in standalone mode.

OTG_FS_IRQHandler is called when data is received from the host device.

Is there a way to determine that when OTG_FS_IRQHandler is called, it is due to data reception ?

Best regards.

[FBL]

Hi @DK3 

USB core generates an RXFLVL interrupt as soon as the received packet is written to the receive FIFO. So, OTG_FS_IRQHandler within the HAL_PCD_IRQHandler, can determine if the interrupt was triggered.