Meeting Notes (2020 10 06)

• The keys on the keyboard work and the LEDs turn on!

• We need to write a proper driver for the LED matrix ICs now

• Progress walkthrough on the dev board

  • pre-run.sh changes
    • Don't need to load the USB module on the BBB that was necessary on the RPI
    • Was able to use config-pin to set the pinmux
      • We could use a config-pin file to store the entire mapping and load that into config-pin
      • Another way we can do it that's good for a final product is to create a device tree for the dev board
  • I2C LED matrix driver
    • Want to add the open & short detection
    • The anti-ghosting has configurable resistance we should configure
    • It would be nice for the driver to automatically switch "pages"; a developer just calls the functionality they want
  • Software matrix layout description
    • Needed to leave holes (:none) in the logical layout to match the physical layout
    • When we get to using the PRUs it may obsolete the current keyboard layout implementation
    • If we come up with a protocol for the layout mapping we could have the keyboard server emit messages to that spec and be able to support input in a more generic way
    • On Xebow the key scan time was 20ms. The current implementation from Excalibur is 2ms.

• We're going to need the frontend to do the key mappings soon

• Boot

  • The RPI is super-slow!
  • The BBB boot time is acceptable.
  • We could have a sidecar app (in Rust?) start up before the BEAM that can read the keymap config so the first key layer works for booting into BIOS

• Powering the LED matrix ICs

  • Currently powered from the BBB 3.3V rail, which can deliver 400mA max
  • We can wire VCC on the dev kit to a 5V rail (USB V+) or add our own voltage regulator to power them separately from the BBB to increase the current (brightness)