[Pairing Failed] Unable to connect with Logitech Unifying Receiver v024.011.00036 using NRF24L01 + Arduino Leonardo R3

[marcioeric]

Hello!

First of all, thank you for the awesome work on this project. I'm currently trying to pair a custom setup using the Unifying protocol but unfortunately haven't had success getting the dongle to respond.

Here is a summary of my setup:

Setup:
Microcontroller: Arduino Leonardo R3 (ATmega32u4)

Radio: NRF24L01 (standard version, not PA+LNA)

Connections:

CE → Pin 7

CSN → Pin 8

MOSI, MISO, SCK → connected via ICSP header (verified with datasheet)

Powered by 3.3V onboard regulator (no external capacitor)

Software: Based on the example code from this repository, modified to send keycodes via USB Serial (very basic A/Z test)

EEPROM: Erased on startup to always force pairing

Dongle version: 024.011.00036

Host OS: Windows 11

[marcioeric]

Quick comment:
This is always the last log.

Transmit: [0xFF, 0x50, 0x01, 0x4B, 0x01, 0x00, 0x00, 0x00, 0x00, 0x64]
Channel: 74
Transmit: [0xFF, 0x50, 0x01, 0x4B, 0x01, 0x00, 0x00, 0x00, 0x00, 0x64]
Channel: 77
Transmit: [0xFF, 0x50, 0x01, 0x4B, 0x01, 0x00, 0x00, 0x00, 0x00, 0x64]
Channel: 5

And, I know that the Dongle is seeing the device because it says:

Software didn't detected a device. Restart and try again.

[decrazyo]

My immediate thought is that this might be some incompatibility between my library and the receiver's v024.xxx.yyyyy firmware. All of my receivers use v012.xxx.yyyyyy firmware so that's what i've tested with.
Logitech keeps the v012 and v024 firmwares in separate directories in their github repo which makes me think that there is some fundamental difference between receivers that use the different major firmware versions.
Do you happen to have another receiver with a v012.xxx.yyyyy firmware that you could try pairing with?

[marcioeric]

Hello!

Thanks for getting back to me — I was thinking the same thing.

After some investigation, I found that the dongle I have (UC0008) uses a different IC — specifically, one from Texas Instruments. That’s likely why the firmware is located in a different folder; it’s an entirely different chip architecture.

I don’t have a dongle with firmware version v012 yet, but I’m looking to buy one so I can test it.

[decrazyo]

That makes sense. I'd been aware that some receivers use a Ti chip but I've never actually encountered one.
Do you know which IC they're using? I'm interested in reading through its datasheet.

[marcioeric]

Yes, I opened it up and the IC is the CC2544 from TI.
You can find the datasheet here: https://www.ti.com/product/CC2544

[taskcpp-collab]

Looking at RQR12.10 dongle firmware I don't see channel 77 used. Channels table length is 24, not 25 as here, and last value is 0x4A (dec 74).

[taskcpp-collab]

Also, I see channel hopping idea is a bit simplified here comparing to original. I suggest restoring restricted list of dedicated pairing channels (seems not used now) and loop via channels indexed 1 4 a d 14 17 2 5 b e 15 18 (hex) having channels same as in 'unifying_pairing_channels' but index 1 started instead of 0.