nRF52840 USB HID Keyboard dropping keys

RE: nRF52840 USB HID Keyboard dropping keys

Yifan — Wed, 18 Dec 2019 00:57:03 GMT

So to clarify, what's the expected behavior of app_usbd_hid_kbd_key_control()?

If I call it multiple times (< 8) then all the keys should show up in the same report right?

If I call it after APP_USBD_HID_USER_EVT_IN_REPORT_DONE, it should send a new report? Is there another way to force a new HID report other than waiting for that event?

I'm not too familiar with USB HID but I noticed when connected to a Mac (OSX), APP_USBD_HID_USER_EVT_IN_REPORT_DONE is seen at an interval even without any calls to app_usbd_hid_kbd_key_control. On Linux and Windows (VM), I see it only after I call app_usbd_hid_kbd_key_control.

RE: nRF52840 USB HID Keyboard dropping keys

Kenneth — Tue, 17 Dec 2019 21:10:16 GMT

The chip markings are good.

I recommend to get yourself an nRF52840-DK, then you will have a ready made hardware and software that work out of the box. I can't really think of anything that fails the way you describe.

Best regards,
Kenneth

RE: nRF52840 USB HID Keyboard dropping keys

Yifan — Mon, 16 Dec 2019 21:30:58 GMT

This is the nRF52840 Dongle (pca10059) (I will provide chip markings when I get home). It is not the DK. I ported the example for pca10056 with minor changes in the config.h. The example code itself works (USB HID device enumerates and key press works).

Unfortunately, I do not currently own a nRF52840-DK.

EDIT: Markings NS2840 QIAAD0 1929AW

RE: nRF52840 USB HID Keyboard dropping keys

Kenneth — Mon, 16 Dec 2019 20:19:23 GMT

Some more questions for debugging:

Can you provide detailed chip markings of the nRF52840?

Is this your own hardware or nRF52840-DK?

Do you experience the same if you use an nRF52840-DK with the nRF5 SDK example project as-is with no modifications?

RE: nRF52840 USB HID Keyboard dropping keys

Yifan — Mon, 16 Dec 2019 16:59:31 GMT

In one approach I tried calling app_usbd_hid_kbd_key_control on the next character as soon as I receive the APP_USBD_HID_USER_EVT_IN_REPORT_DONE event for the last character. In a second approach, I tried calling it in a 200ms app timer. In a third approach, I tried querying a "sent key" flag in a 200ms app timer (the atomic flag set after APP_USBD_HID_USER_EVT_IN_REPORT_DONE) and send the key after seeing the flag.

In all three cases, I see about one dropped key event (key up or down) in about every 3 sent.

RE: nRF52840 USB HID Keyboard dropping keys

Kenneth — Mon, 16 Dec 2019 13:31:29 GMT

What delay do you have between the individual characters in "hello"?

Best regards,
Kenneth