Keychron K2 Reverse Engineering
This is partial and may or may not be completed. Use this information at your own discretion and risk.
This is for K2 RGB v2.
TODO List - QMK support
- Ability to safely flash bootloader
- Ability to revert to factory firmware
- Confirm Chibios functionality
- Get QMK Working
- Get LEDs working
- Confirm bluetooth functionality
Chips
- Main MCU - HFD2201KBA - appears to be based on/clone of SONIX SN32F24xB
- Bt module CYPRESS CYW20730A2KFBG
- Charge IC - TPU5000
Key Matrix & MCU
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MCU-Diagram - Keyboard matrix diagram on the MCU
| --- | col | C0 | C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 | C9 | C10 | C11 | C12 | C13 | C14 | C15 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| row | pin | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 |
| R0 | 64 | ||||||||||||||||
| R1 | 63 | ||||||||||||||||
| R2 | 62 | ||||||||||||||||
| R3 | 61 | ||||||||||||||||
| R4 | 60 | ||||||||||||||||
| R5 | 59 |
MCU-Diagram - LED matrix
| g | b | r | --- | --- | --- | col | C0 | C1 | C2 | C3 | C4 | C5 | C6 | C7 | C8 | C9 | C10 | C11 | C12 | C13 | C14 | C15 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ch1 | ch2 | ch3 | pin | pin | pin | pin | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 |
| Q13 | Q7 | Q1 | 01 | 02 | 04 | --- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --- | --- | --- | --- | --- | --- |
| Q14 | Q8 | Q2 | 05 | 06 | 07 | --- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --- | --- | --- | --- | --- | --- |
| Q15 | Q9 | Q3 | 08 | 09 | 10 | --- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --- | --- | --- | --- | --- | --- |
| Q16 | Q10 | Q4 | 11 | 12 | 13 | --- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --- | --- | --- | --- | --- | --- |
| Q17 | Q11 | Q5 | 14 | 15 | 47 | --- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --- | --- | --- | --- | --- | --- |
| Q18 | Q12 | Q6 | 50 | 49 | 48 | --- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --- | --- | --- | --- | --- | --- |
MCU-Diagram - mac/win and bt/off/cable dip switches
- Bluetooth / O / Cable Mode: pin 57
- Win - Android / Mac - iOS Mode: pin 51
MCU-Diagram - Caps Lock indicator
- Caps Lock: pin 43
MCU Pinout - SN32F248BF
Bluetooth module
seems to be wired like the Blitzwolf BW-KB1(https://github.com/IslamAlam/blitzwolf-bw-kb-1)