Full Speed keyboards not working with icepi-zero-c64

[jwsmart]

I spent a while playing with the icepi-zero-c64 this morning - so far it's amazing.
Unfortunately, I had a lot of trouble finding a keyboard in my house that worked with it, and from what I can tell, it seems like one of the common properties of the keyboards that don't work is that they're all negotiating Full Speed.

Another commonality is that the working, low speed keyboard has a bInterval of 24, and the non-working full speed keyboards have a bInterval of 8 or less.
The bInterval of 8 (the logitech unifying reciever) has some observable output, just not the right keys.
All the keyboards with a bInterval of 1 don't have any effect at all.

A polling interval of 8ms seems quite high for a full speed device with a bInterval of 1 if this article is to be belived

Here's the working keyboard, an absolutely ancient IBM USB keyboard:

Bus 003 Device 006: ID 04b3:3025 IBM Corp. NetVista Full Width Keyboard
Negotiated speed: Low Speed (1Mbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x04b3 IBM Corp.
  idProduct          0x3025 NetVista Full Width Keyboard
  bcdDevice            1.09
  iManufacturer           1 LITE-ON Technology
  iProduct                2 USB NetVista Full Width Keyboard.
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0022
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          4 HID Keyboard
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower               70mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              5 EP1 Interrupt
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      65
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval              24
Device Status:     0x0000
  (Bus Powered)

This is a non-working (but some keys produce some output, just not the pressed keys) when paired with a Logitech K400

Bus 003 Device 012: ID 046d:c52b Logitech, Inc. Unifying Receiver
Couldn't open device, some information will be missing
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x046d Logitech, Inc.
  idProduct          0xc52b Unifying Receiver
  bcdDevice           12.10
  iManufacturer           1 Logitech
  iProduct                2 USB Receiver
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0054
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          4 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower               98mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      59
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               8
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      2 Mouse
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength     148
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               2
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      93
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               2

and some non-working keyboards:

Bus 003 Device 007: ID 3434:0430 Keychron Keychron C3 Pro
Couldn't open device, some information will be missing
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x3434 Keychron
  idProduct          0x0430 Keychron C3 Pro
  bcdDevice            1.01
  iManufacturer           1 Keychron
  iProduct                2 Keychron C3 Pro
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x005b
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      68
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      34
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength     182
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1

This one has some sort of macro capability that I never used, which explains the catch all 64-byte in/out descriptor on endpoint 3.

Bus 001 Device 012: ID 2f68:0042 Hoksi Technology DURGOD Taurus K310
Couldn't open device, some information will be missing
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x2f68 Hoksi Technology
  idProduct          0x0042 DURGOD Taurus K310
  bcdDevice            1.03
  iManufacturer           1 Hoksi Technology
  iProduct                2 DURGOD Taurus K310
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x005b
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      57
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength     164
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.10
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      29
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1

Maybe this one doesn't work because the first interface descriptor is 3/1/2 Mouse?

Bus 003 Device 009: ID 2dc8:5201 8BitDo 8BitDo Retro Keyboard Receiver
Couldn't open device, some information will be missing
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x2dc8 8BitDo
  idProduct          0x5201 8BitDo Retro Keyboard Receiver
  bcdDevice            1.03
  iManufacturer           1 8BitDo
  iProduct                2 8BitDo Retro Keyboard Receiver
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x005b
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      2 Mouse
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode           33 Unknown
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      81
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode           33 Unknown
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      82
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x84  EP 4 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x05  EP 5 OUT
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode           33 Unknown
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength     245
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1

I believe this one is QMK-based:

Bus 003 Device 011: ID feed:b155 John Hawthorn Model H Keyboard
Couldn't open device, some information will be missing
Negotiated speed: Full Speed (12Mbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0xfeed John Hawthorn
  idProduct          0xb155 Model H Keyboard
  bcdDevice            1.00
  iManufacturer           1 John Hawthorn
  iProduct                2 Model H Keyboard
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x005b
    bNumInterfaces          3
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      1 Boot Interface Subclass
      bInterfaceProtocol      1 Keyboard
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      64
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      50
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 [unknown]
      bInterfaceProtocol      0 
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.11
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 (null)
          wDescriptorLength      34
          Report Descriptors: 
            ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x04  EP 4 OUT
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0020  1x 32 bytes
        bInterval               1

[m1nl]

Thank you for a very detailed report; bInterval is advertised in the endpoint descriptor, however I decided not to parse it and just use fixed values. I'm using Logitech Unifying so I'm quite concerned why the very first High Speed keyboard does not work for you. I'll try to decrease polling interval to 1 ms for keyboard HID class by default. I had similar case with 8BitDo devices which refused to work when poll rate was too low. At least it's not a problem with endpoint number - for all of your keyboards it is equal to 1.

I'll also add override for 8BitDo Retro Keyboard Receiver vid / pid pair.

[m1nl]

@jwsmart

I performed some tests with polling interval set to 1 ms and it works just fine with my Logitech Y-R0012 connected to same receiver - the only difference is:

...
  bcdDevice           12.11
...

Here are the changes I added to the development build:
9e05868
icepi-zero-c64-usb-20260511T214304.zip

Can you please test with this build?

Additionally, could you note which keyboard triggers the last LED (the one closest to the edge of the board) after any key press? The USB controller only recognizes the device once a single valid report is received, and only then is that LED turned on.

[jwsmart]

I tested with the new build, not much of a change

VID:PID	Keyboard	speed	USB HID Report Light	Result
04b3:3025	IBM Corp. NetVista Full Width Keyboard	low	light	working
046d:c52b	Logitech, Inc. Unifying Receiver w/ K400r	full	light	sometimes works if 2 keys are held down simultaneously and a 3rd is pressed
2dc8:5201	8BitDo 8BitDo Retro Keyboard Receiver	full	no light	not working
feed:b155	John Hawthorn Model H Keyboard	full	no light	not working

[m1nl]

Thank you for debugging and testing, I really appreciate your help.

1. If Logitech works only when more buttons are pressed at once, it probably means that the HID report is populated randomly (vs. FIFO I was observing with my keyboard). I've increased number of concurrently captured keys to 6 (from 4) and fixed HID report processing. Can you please give it a try?

icepi-zero-c64-usb-20260512T085511.zip

2. My friend owns 8BitDo keyboard, I'll meet him soon and will try to perform some debug. However it looks like this keyboard only supports NKRO - 6KRO should be supported to as it's required by HID standard, but 8BitDo knows better...

3. It looks I'll be able to debug issues with Keychron soon as my colleague uses one at work - stay tuned!

4. For QMK-based keyboards I will be getting atmega32u4, to check why enumeration fails; if you're Linux user, capturing HID packets exchanged during enumeration with Wireshark (https://wiki.wireshark.org/CaptureSetup/USB) could be really helpful.

[jwsmart]

Happy to help!

I've actually got one of these USB sniffers - they are great. My plan was to sit down and capture some working and non working traffic. In the meantime, I'll give that new build a try.

[jwsmart]

OK, the latest build mostly fixes the Logitech. Normal keys are reliable, but It still has trouble with the function keys and print screen, probably related to them being behind an "Fn" key combination.
Here's what it looks like https://secure.logitech.com/assets/46733/19/wireless-touch-keyboard-k400r.jpg

I wonder if the 8bitdo is doing what's described here under "Workarounds for buggy implementations".

Like I said, I'll break out the USB analyzer when I have some more time.

[m1nl]

At least there is some progress.

1. I think I'm not sending SET_PROTOCOL (BOOT) right now, I'll try to add this step in the enumeration process.
2. I'm quite sure that Fn + X is translated inside the keyboard and is not send to the host as a separate key modifier in the report.

I'll let you know, when updated version is ready - I was using Tigard and Sigrok to get raw USB frames from D+ / D- lines, but should be even better for this particular purpose.

[m1nl]

I published a new release (https://github.com/m1nl/icepi-zero-c64), which includes latest changes I added to this core; I'm hoping that forcing BOOT protocol, Logitech keyboard may change the way it provides report for function keys.

BTW, I also added 4MiB REU support (https://github.com/m1nl/icepi-zero-c64#reu-support) .

[jwsmart]

OK, tested 0.0.5. That fixed the last of the issues with the Logitech, and also got the Keychron C3 working.

VID:PID	Keyboard	speed	USB HID Report Light	Result
04b3:3025	IBM Corp. NetVista Full Width Keyboard	low	light	working
046d:c52b	Logitech, Inc. Unifying Receiver w/ K400r	full	light	working
3434:0430	Keychron Keychron C3 Pro	full	light	working
2dc8:5201	8BitDo 8BitDo Retro Keyboard Receiver	full	no light	not working
feed:b155	John Hawthorn Model H Keyboard	full	no light	not working

[m1nl]

Good, I tested the Keychron K2 and can confirm it works (nice keyboard, by the way). I also just received an 8BitDo Retro Keyboard from my colleague and will start debugging it soon.

I’d really appreciate it if you could share HID dumps from the John Hawthorn Model H Keyboard when you have time :)

[m1nl]

OK, I used a logic analyzer to check what’s going on with the 8BitDo Retro Keyboard Receiver, and it looks like my core had too much delay when switching from send to receive transactions. I added an intra-packet delay to ensure I’m not sending subsequent packets too quickly, but I implemented it incorrectly, so the delay was also applied when switching from RX -> TX… my bad.

The keyboard still doesn’t work, though. I changed the interface index from 0 to 1 in all enumeration requests (according to lsusb -v, 0 = mouse, 1 = keyboard), but I’m still not receiving any reports. From what I’ve found online, this keyboard is not very compatible, and it may not support 6KRO at all (NKRO only). I think I will give it up for now.

I’ll clean up the code and make a release - hopefully the thing I just noticed will fix the John Hawthorn Model H Keyboard :)

[m1nl]

I published a new release (https://github.com/m1nl/icepi-zero-c64), which includes latest changes I added to this core; I'm hoping that removing this intra-packet delay which impacted TX->RX switch will fix John Hawthorn Model H Keyboard .

[jwsmart]

OK, finally got a chance to get USB captures. These were all done using 0.0.7
I've added wireshark pcapng (zipped so github would accept them) captures for
the working Logitech K400r, as a reference icepi-logitech-k400r-working.zip

And the non-working 8bitdo and model H keyboards:
icepi-8bitdo-nonworking.zip
icepi-modelh-nonworking.zip

The 8bitdo does look like it only sends NKRO reports.
The Model H (QMK-based) is really strange. Looks like the keyboard keeps resetting?

[m1nl]

Thanks! I'll take a look soon. Still considering getting ATmega to simulate it ;)

[m1nl]

Strange, Model H accepts SET_ADDRESS and SET_CONFIGURATION, but then subsequently rejects SET_IDLE (HID), GET_DESCRIPTOR (HID) and SET_PROTOCOL (HID) [stall] and goes crazy after querying HID endpoint :) no idea what's going on here. Any chance you could get trace when it's enumerated by a regular laptop running Linux or Windows? I don't see any other configuration then default (1) from lsusb you've provided...