You Make Robots Blog

Keeping Retro Computers Alive!

TZXDduino

When I first started developing my own TZXduino PCB boards I was struggling to get it working with my Sharp MZ700 computer. Sometimes it worked and others not. I couldn’t put my finger on it, but then I put a scope on the output of the TZXduino device I purchased from the original guy who made them. I noticed a difference while playing around. I thought about this for a while and had read that LM386 needs to operate at 5v-18v and but really needs to operate higher than 6v to minimize drain. Most of the TZXDuino that were in the wild were driving the LM386 ( or AMP module) from the 5v pin on the Arduino thus allowing it to operate from the Arduino USB power. I noticed that with the drain of other components that only 3-4v was coming out of that pin and it occurred to me maybe that is the issue. So I factored that into the design of the PCB. Sometime later I found myself in a similar situation with certain ZX Spectrums. After digging about I found out some older models of the ULA chip can go a little deaf. In my own systems, I was fixing this issue by replacing the ULA. Fast forward and I decided to architect in the fix I had included for my Sharp MZ700 into my main PCB I use for all the other Retro Computers.. I’m calling it the Deaf Computer option. Now I cannot guarantee it will fix all your problems but Wayne over at Retro Robbins offered to test this theory out for me since he had a deaf Spectrum 128K+. Watch the first part of the video and decide for yourself.

Deaf Computer Test.

Someone gave me an idea to document the firmware feature differences that the TZX_Tools firmware tool supports. TBH It is a good idea so we can dispel the myths and views on the different firmware as they all do something a little different. From this table, you can see why I prefer MaxDuino. Even more than my own firmware Digiwavuino. I’m sure over time I’ll have to update it and I’m sure there will be 1 or 2 incorrect entries but this is my view on the features.

FYI TZX_Tools is a tool that allows for simple updating of devices running the below firmware.

FeatureMaxDuinoTZXduinoCASDuinoArduiTapeDigiwavuino
OLEDYYYYY
LCDYYYYY
8544 SCREENYYYYY
RGB LCDNYYYN
ROTATE OLEDYNNNN
DYNAMIC SCREEN DETECTIONNNNNY
DYNAMIC SD DETECTIONYNNNY
CHANGE SD CARD WITHOUT RESETNNNNY
TAP FILEYYNNN
O FILEYYNNN
P FILEYYNNN
TZX FILEYYNNN
TSX FILEYNNNN
CDT FILEYYNNN
UEF FILEYYNNN
CAS FILEYNYNN
WAV FILENNNYY
REMOTE JACK FOR MULTILOADYYYYY
MUTLILOAD GAME SUPPORT FOR ZX SPECTRUMYNNNN
ARDUINO NANOYYYYY
ARDUINO UNOYYYYY
ARDUINO MEGAYNNNN
ARDUINO NANO EVERYYNNNN
THINARY EVERYYNNNN
STM32YNNNN
STORE LOGO IN EEPROMYNNNN
ENCHANCED SDFAT SUPPORTYNNNN

I realized very early on, that people wanting to update their TZXduino, MaxDuino, CASduino, or ArduiTape would struggle if they had no experience with the Arduino programming tool. So I built a FREE tool to do that for you in a way to give back to the Retro Community. Watch the video below and CLICK HERE if you want to download the tool.

Nice video from Wayne Robbins who is a big-time ZX Spectrum vlogger in which he shows off multiple ZXuitape models which allow you to load games on ZX Spectrums from SD card. He had an issue with one which I later identified as a problem with the SD card Wayne was using. Also Wayne referred to them as a TZXduino which is not technically true. ZXuitape uses the MaxDuino firmware which is far superior. Wayne is awesome in the community so I’ll let him off this once 😉 If you want to buy one for yourself CLICK HERE