The previous version did not work on MCUs that only had USB device mode
(compared to OTG) because of the handling of NAK. And this previous
handling of NAK had a race condition where a new packet could come in
before USBD_HID_SetNAK was called (since USBD_HID_ReceivePacket clears NAK
as part of its operation). Furthermore, the double buffering of incoming
reports was not working, only one buffer could be used at a time.
This commit rewrites the HID interface code to have a single incoming
buffer, and only calls USBD_HID_ReceivePacket after the user has read the
incoming report (similar to how the VCP does its flow control). As such,
USBD_HID_SetNAK and USBD_HID_ClearNAK are no longer needed.
API functionality from the user's point of view should be unchanged with
this commit.
The new configurations MICROPY_HW_USB_MSC and MICROPY_HW_USB_HID can be
used by a board to enabled or disable MSC and/or HID. They are both
enabled by default.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
Damien George