Update attiny firmware on StepperUNO

Overview

On the stepperUNO there are 2 attiny microcontrollers. Their purpose is to send the step clock signal to each motor.

Both of them contain a firmware that might be needed to update.

Note that you might have to use the right library version against the version of the attiny84 firmware. See the compatibility table below.

Library	Attiny firmware
stepperUNO 1.4	attiny_stepperUNO_v1.2.ino attiny_stepperUNO_v1.3.ino
stepperUNO 1.4.1	attiny_stepperUNO_v1.2.ino attiny_stepperUNO_v1.3.ino
stepperUNO 1.5.0	attiny_stepperUNO_v1.4.ino

Download

The attiny firmware is an Arduino sketch provided in the library itself.

Open the library zip file then go to the examples folder.

The appropriate attiny sketch is called attiny_stepperUNO_vx.x.ino.

Locate the attiny's

The attiny's are the chips circled on the picture below.

The programmer

The recommended programmer to program the attiny's is the Nanoprog

Prepare the IDE

We will use the Arduino IDE to program the attiny's.

Download it from the arduino website and install it. https://www.arduino.cc/en/software

In the IDE go to Tools -> Board: -> Boards Manager...

In the filter box on the top just enter tiny. Then the package ATTinyCore by Spence Konde will appear in the list (usually the first entry). Install the latest version of this package.

Now open the attiny sketch with the IDE. Then select Tools -> Board -> ATTinyCore -> ATtiny25/45/85 (no bootloader)

Prepare the chip

Pay attention to the polarity mark on the attiny and the way they are mounted.

Remove one attiny chip form the stepperUNO. Be really careful and gently lift it with a flat screw driver from both sides.

Place the attiny on the Nanoprog. Make sure the polarity mark is facing toward the inside of the Nanoprog.