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Volunteer get! Thanks @David Cook ! Unfortunately the limiting factor here is the ROM rather than the interface - to my knowledge, no other Powerbooks have HD20 support in ROM - though the cable would still be good for connecting a Floppy Emu as a floppy drive. If anyone else is interested...

It's time for another Tashtari shenanigan. (You don't see that word used in the singular very often, do you...) So here's the situation: I'm about 99.9% sure that the Powerbook 100 has HD20/DCD support in ROM, but I want to be 100% sure. As with all machines with HD20/DCD support, the device...

These are things that I'm not going to be able to explain very well (I'm not an electronics engineer either), but I'll try - anyone who knows better, please correct me. Yes, technically a 10.1 µF capacitor would have the equivalent capacitance of both capacitors, but it's slightly more...

The 2.8 volts figure is what I measure between ground and Vcc, is that what you're asking? I'm not sure I understand the question.

Success! With a little help (okay, a lot of help) from @zigzagjoe, TashSync is now working on the IIsi without an external power supply! He noticed that the PIC's own protection diodes could be used in lieu of external diodes to rectify the composite sync signal to provide power as long as...

Lot of shifting goalposts in this project. Partially the fault of my own particularities, but as usual I'm also learning more minute details of my favorite PICs as I go. With the three PIC10F320 firmwares (firmwares? firmware programs? units of firmware?) complete, I'm now trying to...

The Toby firmware is working! ...From a simulated signal, at least. Don't have a real Toby card to test with (or a Mac II, for that matter). It should also work for that SE/30 card whose name escapes me that has a flat horizontal sync pulse but no serrated pulses, but I haven't set up a test...

So far so good! I have PIC10F320 firmware now that I've confirmed to work on the IIsi on at least one monitor which I know doesn't support sync-on-green. Same should work on the IIci, though I don't have one of these to test on. PCBs on the way, and we'll see whether I'm physically capable of...

Yeah, most likely. I was mainly intending to use it over the flat interval in the Toby card's composite signal where the signal has to be synthesized, rather than full time. This is what I'm depending on. =D So far it seems to hold true, fingers crossed that that continues to do so, because...

As I continue to chip away at this, I'm getting more into the mindset that a single adapter to do All The Things is not the approach I want to take... I think I'd rather make different pieces of firmware for the PIC10F320 that handle specific cases and adapters to go with them. One adapter for...

Oh, interesting, the 12F1501 doesn't have OSCTUNE (for that matter, neither does the 10F320/322)... that's strange, I never noticed that before. OSCTUNE would be the usual way to fine-tune the oscillator, if it existed, and I don't see anything that replaces its functionality. I did try...

Ah, interesting. The PIC can take as little as 2.5V, so that has potential... the only worry would be that the logic levels go down with the supply voltage and I'm not sure what happens with that. Outputting 4.3V would be fine as that's enough to be considered a logic high, but if the PIC's...

I took a small break from the main project to make a sync processor for the Apple IIgs (and just the Apple IIgs) and was astonished to find that it actually worked the very first time I ran the code, which never happens. Code is up on Github in case anyone's interested. I'm having a few PCBs...

Rambling ahead, you've been warned. Continuing to chip away at this. Rewrites are always a bit disheartening, but I have to remind myself how many times I had to start over on TashTalk before I made it work. In any case, I think the architecture will be more flexible than before with this...

Great, thank you! PM sent.

On a whim, I took a look at my IIgs's sync signal (probably should have done this sooner) and discovered it's a fairly different animal than the IIsi. Where the IIsi has the falling edges of the sync signal in the same place throughout the frame - it just moves the rising edges further ahead...

It works! On one combination of computer (IIsi) and monitor (Dell E151FP), anyway. This is the first time I've tested it with real hardware and not just a PIC I programmed to spit out simulated sync signals, and it passed with flying colors! I suppose the next thing to do is to knock together...

I did a rewrite of the code that profiles the composite sync signal and freed up a considerable amount of code space... I am now where I was before but hopefully a on a bit more solid ground. Going to have to do some more testing with real Macs and see whether my signals are precise enough for...

On second thought, don't. It's a neat little chip but experimentation reveals that it's missing too many features to do this job well. The 1501 will do much better. (And, failing this project, I already have a few others that it can be used for...)

Cool! Grab a PIC10F322 as well while you're about it, they're super cheap.