These are preliminary notes on support for Meshtastic in the Pinetab.
A RF95 is connected via a CH341 USB-SPI chip.
Pin assignments: CS0 from RF95 goes to CS0 on CH341 DIO0 from RF95 goes to INT on CH341 RST from RF95 goes to RST on CH341
This Linux driver claims to provide USB-SPI support: https://github.com/gschorcht/spi-ch341-usb Notes here on using that driver: https://www.linuxquestions.org/questions/linux-hardware-18/ch341-usb-to-spi-adaptor-driver-doesn%27t-work-4175622736/
Or if absolutely necessary could bit bang: https://www.cnx-software.com/2018/02/16/wch-ch341-usb-to-serial-chip-gets-linux-driver-to-control-gpios-over-usb/
- How to access SPI devices via ioctl (spidev): https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md#:~:text=Troubleshooting-,Overview,bus)%2C%20UARTs%2C%20etc.
- access GPIO via libgpiod?
- Use dkms to distribute driver?
- echo 100 > /sys/module/spi_ch341_usb/parameters/poll_period
Port meshtastic to build (under PlatformIO) for a POSIX target. spec: no screen, no GPIOs, SIM network interface, POSIX threads, POSIX semaphores & queues, IO to the console only Use ARM Linux: https://platformio.org/platforms/linux_arm And Linux native: https://platformio.org/platforms/native
Test cs341 driver - just test reading/writing a register and detecting interrupts, confirm can see rf95
Make a radiolib SPI module that targets the cs341 (and builds on Linux)
use new radiolib module to hook pinebook LoRa to meshtastic, confirm mesh discovery works
Make a subclass of StreamAPI that works as a POSIX TCP server
Use new TCP endpoint from meshtastic-python