eco_cool Display Module Programming

Programming the ATTiny261A on an eco-cool display module

A while ago a co-worker gifted me with several of these display modules.
Initially I thought "well, it's got a nice dual 7 segment led display but not much else worthwhile" but after closer inspection I found it was driven by an Atmel ATTiny261A microcontroller. Suddenly, these gizmos were a lot more interesting!

Here's what it looked like...

I sorted out the necessary connections for my USBASP programmer (VCC, GND, MISO, MOSI, SCK and RESET) and found 4 of them were already tied to the 5 pin connector on the module so only 2 additional connections were really necessary.
I did a quick check of the lock bits on the ATTiny261 and found that the maker had them set to prevent downloading of the original programming.
Once a few more connections were figured out it was a relatively simple task to load some new code into the module. I started out just making the LEDs display digits and count from 00-99 but later added a bit-banged serial interface allowing me to connect to a terminal program through a USB-Serial adapter.
I finally added some functions that allowed me to send commands to make it beep, change the count rate, pause the count and update the digits.

Download Link Details:

ATTiny261A.pdf ATTiny261A datsheet

Arduino as ISP for ATTiny261A.docx A word document with instructions for programming the device with an UNO

eco_cool.pdf Partial schematic of major components

eco_cool2.zip Display demo software (source, .hex and a couple of batch files)

eco_cool2_ASM.zip Example of programming in AVR assembler (includes the AVR assembler avrasm2.exe)