Well, my friends, I have some bad news: the alternative joymega adapter made with a transistor doesn't work properly. It's temperamental and depending on the MSX model, joypad and combination of buttons pressed it glitches.
You mean the design by roadfighter? I have one made by him, I used it not that often but I had no problems with official sega pad and a decent 3rd party (made by ascii!!) megadrive pad. This on a sanyo wavy phc70fd2 and I tested it in your joytest tool and played some games with it.
What are the requirements to trigger the glitches? (any known model or keypress combinations where it may fail)?
I'll do some tests if the NC7ST04 "TinyLogic" chip can be used to build an adapter and post the results here.
What will be different with this design? easier to build? Or just works better in general? I am thinking of trying to build one myself later (need to get a soldering iron first).
What are the requirements to trigger the glitches? (any known model or keypress combinations where it may fail)?
Here, with an original Sega SJ-6000 joypad and an FS-A1ST, it glitches when I press the B button. I tried decreasing the pull-up resistor from 10K to 4K7, then it started glitching only when B+C where pressed.
I decreased the pull-up to 2K2, and it solved almost all glitches, but still glitched when I pressed B+C+X+Z.
When it still had the 10K pull-up resistor, this very same adapter worked fine on a Zemmix-BR and a Sony HB-F1XDJ. But no luck with the TR, either in Z80 mode or R800 mode. Curiously enough, the clone joypad from DX works fine in all situations.
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What will be different with this design? easier to build? Or just works better in general? I am thinking of trying to build one myself later (need to get a soldering iron first).
The design with the NC7ST04? The only advantage will be of being very compact. But it's an untested design.
If you're going so solder one joymega yourself, the only recommended/reliable design until now is the original with the 74LS04 chip. Oh, and remember to connect all unused inputs of this chip to the GND.
Sebbeug: ordered from ebay? I asked someone a year ago and he said it worked without problem, 6 buttons and AFAIK on a turbo r. But I don't know how extensively he tested it.
@sd_snatcher can you tell if that one on ebay is using the 74LS04 or transistor? I am a total noob with electronics but I looked up pics on google and I dont recognize the inverter chip on that ebay one.
*edit* I looked up the transistor design, it looks like that ebay one is using 1x transistor 2x resistor.
Already made a pcb design with the NC7ST04.
When the results are what they need to be ( waiting on sd_snatcher to post the results) i will order some boards to make some pcb's.
But first things first, lets wait for the results.
