Pete Johanson published his Zaphod Lite, a hand solderable version of the original Zaphod – a feature-rich low-pro wireless monoblock split.
Published June 25, 2022
After validating the final protos, Pete Johanson made the Zaphod Lite open source.
This is a hand solderable version of the original Zaphod, using any XIAO footprint controller.
Speaking of XIAOs, are you aware that kbd.news has a collab with Seeed Studio? Claim your free prototype here.
- Runs ZMK firmware
- supports @seeedstudio XIAO family of controllers (BLE pictured)
- Adafruit Sharp memory display (1.3")
- Kailh Choc v1 with MoErgo MCC legend sample keycaps
- TI shift register for extra IO
As Pete notes, for power efficiency reasons, when using a XIAO BLE, all input pins (rows, since using col2row diode direction) stay on the controller's GPIO pins directly so that interrupts can be detected to trigger scanning, allowing the controller to idle otherwise.
Outputs done via two controller pins and the shift register, so it can set all outputs high when idle to detect interrupts and start active scanning; and also set only one output pin high at a time, when needed for active scanning.
Shift registers, according to Pete, aren't technically SPI devices, but can share an SPI bus with other devices, "thanks to the RCLK pin acting roughly the same way a Chip Select (CS) pin does for an SPI peripheral".
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