STM32 CH592 / Trichord
This page covers the common operations and limits of the STM32L412 + CH592 wireless architecture (Trichord for short), used by F60w, Manta40 rev2, and Manta40 rev2 Ortho.
Trichord uses a different MCU and protocol from the AVR family (Bluefruit/DuoChord/AVR+CH592); firmware is not interchangeable.
How it works
- The STM32L412 handles QMK matrix scanning, USB, keyboard state, and local power management.
- The CH592 module handles wireless transport (2.4G and BLE); the STM32L412 drives it over UART with a binary frame protocol.
- Enters low power (Stop2) after about 5 seconds without input; wake-up is driven by matrix row interrupts.
- Supports USB / 2.4G / BLE connection modes.
Trichord wireless keys
| Key | Action |
|---|---|
| 2.4G / CH0 | Switch to the 2.4G receiver channel |
| BLE1 / CH1 | Switch to Bluetooth channel 1 |
| BLE2 / CH2 | Switch to Bluetooth channel 2 |
| BLE3 / CH3 | Switch to Bluetooth channel 3 |
| BLE4 / CH4 | Switch to Bluetooth channel 4 |
| BLE5 / CH5 | Switch to Bluetooth channel 5 |
| PAR | Put the current channel into pairing mode |
| CLR | Clear all pairing records on the keyboard (double-press within 1 second) |
| TOG | Toggle between USB and the most recent wireless channel |
Command mode shortcuts (advanced)
Hold both Shift keys first, then press a command key:
| Command key | Action |
|---|---|
| Tab | Switch to 2.4G |
| Q / W / E / R / T | Switch to BLE1 / BLE2 / BLE3 / BLE4 / BLE5 |
| U | Switch to USB |
| C | Quick toggle between USB and wireless |
| X | Put the current channel into pairing mode |
| Z | Clear pairing data (double-press to confirm) |
| V | Check battery level (percentage output) |
First-time use
- Press 2.4G or BLE1–BLE5 to pick the target channel.
- If the device is not found, press PAR to enter pairing manually.
- If old pairings interfere, press CLR twice within 1 second and pair again.
See Trichord Basic Operations for the full procedures.
Limits and notes
- Trichord models (F60w / Manta40 rev2 / Manta40 rev2 Ortho) firmware cannot be mixed.
- Low power relies on matrix row interrupt wake-up; if the keyboard does not wake from sleep, check known issues related to firmware and low-power assessment.
- Specific slot and power behavior follow the model pages and the repository assessment docs.
Troubleshooting
- Cannot connect or pair: see
Troubleshooting / Wireless. - No response after sleep: see
Trichord device differences. - Flashing failures: see
Firmware Downloads & Flashing.