RC Dual Motor Driver firmware for ATmega MCUs

This firmware turns an ATmega MCU into an RC (radio control) bidirectional dual motor driver:

• By default, RC channel 1 controls forward/reverse for both motors while RC channel 2 controls differential steering between them.
• In independent mode, RC channels 1 and 2 control the motors independently.
• iBUS servo interface can be used to connect to a FlySky receiver.
• Controls need to be returned to their initial positions (re-armed) on startup or signal loss.
• Status LED indicates how many RC channels are active by blinking that number of times.
• Watchdog resets the device in case of signal loss.

Supported MCUs

• ATmega16U4
• ATmega32U4 (Teensy 2.0, Arduino Micro/Leonardo)
• ATmega32U6

Dependencies

• cmake
• avr-gcc
• avr-libc
• avrdude

Installation

Check out #define statements at the beginning of src/config.h to see if you need to change settings before building the firmware. Options to consider:

• The default PWM frequency is 16kHz at 8Mhz clock. It can be decreased by a multiple of 2 using the PWM_DIV value. It can also be doubled by switching to 16Mhz clock via the CLK_16MHZ option.

• The output pins can be inverted via the *_INV options.

• If iBUS is used, RC-to-RX channel mapping can be configured using the IBUS_CHx values.

To build, run (with your own MCU):

cmake -B build -D MCU=ATMEGA32U4
cd build
make

To install on the device using AVRDUDE, run (with your own programmer):

make PROG=usbasp flash

or for Teensy 2.0:

make flash-teensy

Pinout

Pin	#	I/O	Description
D4	4	IN	RC channel 1
C7	13	IN	RC channel 2
D2	0	IN	iBUS servo
D7	6	OUT	PWM 1
B6	10	OUT	PWM 2
F7	18	OUT	Forward 1
F6	19	OUT	Forward 2
B4	8	OUT	Reverse 1
B5	9	OUT	Reverse 2
D6	12	OUT	Status LED

Numbers denote Arduino pins.

Building a dual 12A bidirectional ESC

Check out this How-To for more information.