QuarkOne - Bootloader
By: ManCave Made (Mitchell A. Cox)
A bootloader for the Atmel XMEGA 128A4U based on LUFA (https://github.com/abcminiuser/lufa) and the AVR911 protocol, with a serial pass-through mode for programming the ESP8266.
The hardware is open source under the CERN OHL v1.2 license: https://github.com/ManCaveMade/QuarkOne-Hardware
Activating the Bootloader
To activate the bootloader, "double click" the reset button (or use the RST pin with a button) within 750 ms. The bootloader flashes the onboard LED with two fast flashes every second.
You will have to install the .inf driver file before plugging the Quark One in (otherwise no drivers will be found). See below for instructions.
The bootloader should show up on your PC as two separate CDC serial ports. One port is an AVR911 compatible bootloader for the XMEGA. You can use AVRDude to program the microcontroller via this port. If you can't tell which port this is, send a '?' via a serial console and it should echo a '?' back.
The other serial port is a transparent passthrough to the Quark One ESP8266 (ESP-01) module. You can flash the ESP-01 using esptool without any modifications. The Quark One bootloader passes the DTR and RTS signals through to the ESP-01 to allow esptool to control which mode the ESP is in. Typically, the ESP passthrough is the first serial port.
The ESP passthrough has been tested with the Arduino IDE in 'Generic ESP8266 Module' mode. Simply make sure the correct serial port is selected and most of the examples should work! The WiFiScan and ESP8266HTTPUpdateServer seem to work nicely.
See the official ESP8266 Arduino Project for details and instructions: https://github.com/esp8266/Arduino
The burn performance of esptool seems to be quite low (I'm not sure if this is normal). However, I have tested the Quark One up to 921600 baud and the speed is certainly better than at 115200. You can set this in the Arduino IDE. I suspect that there is a timeout happening in the LUFA USB CDC framework which is impairing performance but for now at least it works!
The XMEGA microcontroller on the Quark One should be compatible with the xmega-arduino project. Work is in progress to update and create the relevant board files to facilitate this process.
See my forked repository for work so far: https://github.com/ManCaveMade/xmega-arduino
You may find that the USB device on Windows is unrecognised. On Windows, download the QuarkOneBootloader.inf file from this repository and in the file browser, right click it and "Install" the driver. This will enable Windows to recognise the USB IDs as CDC devices.
MIT License. Copyright (c) Mitchell A. Cox (mitch[at]enox[dawt][co][dawt]za)