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STM32F4 Custom HID device, host read callback



I am new to HID and have some questions regarding the ST HID Middleware package.
I am using an STM32F479F as a Custom HID device. I used the example from the STM32 USB training to get everything up and running. It works.

When the host (PC) performs a write, then there is a callback to the USBD_CUSTOM_HID_DataOut function. I can process the request, and when everything is finished, I would use the USBD_CUSTOM_HID_SendReport function to send the data out. Only then the callback to the USBD_CUSTOM_HID_DataIn appears to be triggered.

For my understanding, I get a write from the host, process the data, and when it is done, I transfer the data out. Independently from a host read operation. Is this true?

Is there a callback in the ST HID Middleware which is triggered when a host read request arrives?

Thank you.