A project log for Z80 Reverse-Engineering And Hacking Adventures

What else can I say?

Eric HertzEric Hertz 08/17/2022 at 04:522 Comments

Wrote up a draft what seems quite some time ago, basically about this same thing... Why not just post it? Dunno, maybe my brain's in a slightly different place, now, and I can go back and compare...


I guess it boils down to "I'm beat."

I mean, it seems fair, considering this project was pretty much the only thing I was doing for months, aside from... well, Let's just call it a fulltime nonpaying job, with a lot of overtime.

I'm not exactly incapable, now, of seeing the project-ideas I had for this, the ideas which the ihex-flasher was to enable... the ideas I'd built-up all last year while working on #Vintage Z80 palmtop compy hackery (TI-86) ... but I sorta can't see them, either.

I guess the question, somewhere, was what was the goal...? And, well, I really dunno.

Flashy doodads were supposed to be the icing on the cake after the ihex-flasher, but then my flashy-doodads turned out to be a huge amount of work; 3.3V level-shifters aren't so bad, unless they need to be wired to FFC connectors, and so-forth. I've, unquestionably, done these sorts of things with point-to-point wiring before, was worth it, then... but right now just doesn't seem that way.

Oh, I remember... One idea was printing highlighter-ink in red and green in a grid on a transparency, and backlighting that with blue-LEDs... Turning a B/W display into color... Actually, that's kinda intriguing just to see how it looks. But, yeah, gotta either get a color inkjet that has highlighter cartridges, or hack mine...

I had actually looked into that a little, way-back... the oldschool B/W bubblejet I've got has such a standard cartridge that they can still be bought, and the service manuals actually show the pinouts and timing(!). Turns out the color cartridge is nearly identical, they basically just rewired a couple pins and divided up the 64 B/W nozzles into 48 total for CMY. It'd probably be an easy hack.

Top that off, when I worked on #The Artist--Printze , one of the important factors was modifying the driver because, at the time, I thought the cartridges were surely too old to still be available... Printze's cartridge was empty and easily hadn't been touched in twenty years. After refilling it with ink from the cheapest cartridge I could find locally ($5), it turned out that the first 16 nozzles were non-functioning. So, I modified the driver to print with the 48 remaining.


So, I guess, it'd be pertydurnsimple to go from there to use that color cartridge with its 48 nozzles.

Heck, I wouldn't even need to make the driver color, knowing which nozzles to use. Hmmm....

Oh, wait... no... dropping different colors in the same row means printing that row three times... heh. Well, I also have a pretty thorough understanding, now, burried in there somewhere, of how to control it manually (via my own software)... Which, actually, might be better, as I have no idea whether the fluorescent ink drops would be thick nor dense enough to convert all the blue.

Heh. Well, this is *sorta* a welcome aside from the weeks of "beat."

I dunno, it seems a bit crazy. 

And, well, the idea of a fluorescent display with a blue backlight, it turns out, was actually patented, many moons ago.

And, dagnabbit, look at those mofos on the youtubes... I didn't even choose to make a "short" of the next vid, wherein I had three colors, I even tried everything I could to *not* make it a "short"... Now analytics says most its views were from "the shorts feed" (youtube *seriously* shared *that* with *everyone*?!), and I got friggin downvotes! I feel kinda bad right now, TBH. Sheesh! Youtube is a friggin' bully, trying to draw in other bullies! Good thing I've got 30-some years of slightly thickened skin, I wonder what the next generation gets out of this!


Anyhow, I know it'd be very different from "the real thing". Real color LCDs put the filter *inside* the glass panel next to the liquid crystal so that the viewing-angle doesn't have to be *perfectly* head-on, lest you see colors that weren't intended from light from, say, a green pixel going through a red filter when the glass is tilted.

So... I'm *expecting* that effect, and actually thought it might be kinda interesting to see what it looks like. "filter" on the back, vs on the front might be best, and could plausibly allow for an interesting look with solid-color pictures, like cartoons... Filter on the front might be interesting, similarly, but maybe with a "sharkskin" effect, which could actually be pretty interesting for, e.g. my idea of using *several* of these displays, each displaying a large single letter.


None of this, by any means, requires a z80 machine... I just figured since it's already running, I might-as-well use it for experimenting with ideas like these.

I guess I'd kinda contemplated coding such experiments on the machine itself, but I guess there's really no reason for that.


Well, it's an idea, anyhow.

In the "draft" log from a while back I started a list of such ideas. Most were far more specific to the z80 and the machine, itself. I even looked into interfacing a Virtual-Memory chip meant for the Motorola 68K series with it, as well as ISA cards. I dunno... 

Another idea is streamlining the "bring-up" process a bit, so it could be used for other devices, which, actually, was a major driving factor in this project... The fact output from C can be hand-tuned means that as long as your chip has a C compiler, you could bare-metal it from the getgo in C, without a pre-provided CRT, headers, etc.... Which would mean that pretty much the exact same learning-process could apply to most chips/systems basically immediately after one's first toggle-switch experiments.

I've gone on about that one several times (maybe limited to drafts?)... And, well, it gets a bit lofty; suggesting a sort of "universal assembly language" and a C compiler that compiles to it.

But, since the ihex-flasher, I guess, it started snapping me back to reality. I mean, sure, such a thing might be doable, but what's the use? E.G. with the ihex-flasher, it *requires* a Von Neumann architecture, because the flash chip can't be both read and programmed at the same time, so the flash-programming code has to be run from RAM, unless you've got two chips... which... is kinda the point. The hardware attached to the device, and how it's attached, has a tremendous impact on how it gets programmed. So... Even with some sort of universal *language*, there's still a need for *very specific* coding....

...And... Here I'm beat.

At that point, yah mightaswell have a C-Runtime, and write drivers for linux. Or Arduino. Arduino on a Z80? 6502? I guess, now that I think about it, I was sorta going for something like that. Hah! I'm really not even particularly fond of what arduinos have brought to the table... as far as inspiring good coding practices and low-level understanding.

I dunno.

Maybe that's why I'm beat. I dunno.


ziggurat29 wrote 08/19/2022 at 03:10 point

it's the heat

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Eric Hertz wrote 08/19/2022 at 08:54 point

...why I'm beait?

The heait?

Well, that may very well be eait, but I feel so incompleait.

[I think I might be low on electrolytes... sorry].

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