USB HID interrupt endpoint packet size

[abstract1340]

Hi Nordic temas,

Now I'm using nRF54H20 with High Speed USB, We currently want to use a custom HID device to transfer a large amount of data using the interrupt transfer (bulk transfer is not considered). Transferring 64 bytes per packet works fine now, but we would like to increase the packet size to 1024 bytes per packet. We're wondering if this is possible and what modifications would be required. Thank you.

[Turbo J]

Terrible idea. If you have lots of data to transfer just use a bulk endpoint, period. Driver troubles? WinUSB and OS descriptors exist.

You can look at the usb_next stack thats is being written with USB 2.0 high speed in mind - no idea whether it supports large interrupt EPs, I did not look that up.

USB 1.1 full speed does not support Interrupt EPs with more than 64 bytes - you would absolutely need high speed here.

[abstract1340]

Hi Turbo, thanks for your reply, I'm currently developing a mouse device. Normally, interrupt endpoints are used for this. So, if I need to transfer large amounts of data, should I add a bulk endpoint for transferring large amounts of data? How should I modify it? Currently, I'm using the new usb_next stack. thanks

[Amanda Hsieh]

Hi, 

You can use this sample https://github.com/nrfconnect/sdk-nrf/tree/v3.1.1/samples/zephyr/subsys/usb/hid-keyboard with large_in_report.overlay and large_out_report.overlay, and modify the size to 1024. 

Regards,
Amanda H.

[abstract1340]

Hi Amanda, thanks for your reply, I have modified size to 1024, but there will be a warning. Is this a problem?

[Amanda Hsieh]

It depends. If the interface with alternate setting is not the last one, then it will fail to set alternate setting. If the interface with alternate setting is the last one (and there is only one interface with alternate setting), then this shouldn't cause problems.