Dragonfly Precharge Firmware

Changelog

• V1.0.0: Initial version

Build Requirements

Make

Ensure make is installed.

Platform IO + pymcuprog

• Install Platformio Core
• Install pymcuprog

Flashing the firmware

Flashing is via the UPDI pin on the attiny404 IC. The programmer is the a serialupdi type, and a simple UART based UPDI programmer can be built using a USB-->TTL UART adapter (e.g. the ubiquitous FTDI232RL adapters), with a 1K resistor connected between TX and RX

                        Vcc                     Vcc
                        +-+                     +-+
                        |                       |
+---------------------+ |                       | +--------------------+
| Serial port         +-+                       +-+  AVR device        |
|                     |      +----------+         |                    |
|                  TX +------+   1k     +---------+ UPDI               |
|                     |      +----------+    |    |                    |
|                     |                      |    |                    |
|                  RX +----------------------+    |                    |
|                     |                           |                    |
|                     +--+                     +--+                    |
+---------------------+  |                     |  +--------------------+
                        +-+                   +-+
                        GND                   GND

To build and flash the firmware (once the programmer is connected to the board):

make upload