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Not cloning the card actually, just the first few parts of its front end that feed Page Buffer data input to FPGA in place of VRAM. No need for VRAM at all, just ROMs and probably that one GAL will be on the Rev.1 board as in the diagram above. The point would be using the existing Radius...

COOL! Didn't know that'd be possible. I've been wondering about doing something on the order of a MacPaint program with a full screen 864x640 canvas to play around with mapping pixels. Doing it visually, comparing baseline screen output with what the Pi is doing might be fun for a bit and then...

Yep it's mapped to the PDS Slot's address space, but the buffer data will be in VRAM and inaccessible to the CPU for all practical purposes, no? VRAM outputs don't head back to the CPU, no need for that at all on a VidCard. Indeed, I just grayed out the extraneous bit about Vampire Video and...

Interesting, but the Page Buffer is built up in VRAM sequentially in alternating cycles split with other CPU activity. AFAIK it never exists as a whole on the system board, that's what VRAM is for after all. Not sure you'd be able to capture the Page Buffer from a Vampire Video subsystem on the...

Can't see the traces yet. I need to test this card, the one I got recently was listed as tested good and will be set up first with output running through the Extron Scaler. Then on to the original board. After it tests good, I'll be de-soldering VRAM. I'll get a good pic of the traces under...

Pi Zero's been approved as a good proof of concept platform. Just checked, Pin 5 is a data line and not tied together. Wouldn't expect them to be. Haven't looked at data lines yet, why do you ask? As a first step, I want to use Pi in parallel input mode to sort out data line load order for...

Bad news just got worse from the serial output point of view, but maybe a whole lot better from mine? Pretty much verified the confusing first findings and buzzed out another mystery after poking at the lines you asked about. SOE is tied together as well! Guessed I'd be finding something...

I'll give it a shot: That's pretty much it, butPi Zero 2 W will probably only do "every so often frames" which may or not be rotated. Pi 5 with 4x Cores/2.4x Clock might be able to do it? Ultimate goal is taking the project to FPGA, much as in the PCB Representation I just did. In that full...

I guess I should explain the point of the overly complicated wire wrap prototype. Aiming toward doing a PCB set up like so. To run the adapter sans VRAM, only the sense line on the board's connector needs to be shorted. Likely will need to be shorted to run output from the connector/cable...

Need some advice from you digital circuit design guys. GPIO advice would be much appreciated as well. Will divining the load order of the Data lines be practical in the parallel input mode? They're related to the addressing inputs, but that seems like a lot more programming if possible at all...

Some folks have been wondering about what I've been posting in another thread I've been using as a Development Notebook, so here goes: Developing a carrier board to interface with the first gen Radius FPD/SE's four VRAM Chips. They'll be de-soldered and then inserted into wire wrap...

Amen to that. Had a run in with one of the know it all "Consultants" that ran NYMUG back in that day. When I said QuickShare's SCSI transfers were faster than Ethernet he insisted 10bT was faster. Explained that 8Mbyte/sec. was much faster than 10Mbit/sec and he came back with the typical...

That's the card I lusted after! But I was never able to put the money together to consummate that fantasy. 8bit/16bit ISA expansion cards in a PC engulfed by the IIx was a siren song almost too hard to resist for one application in particular.

QuickShare (1987) was a similar setup that connected the SCSI Port of my SE directly to the QuickShare SCSI Card in my Tandy 1000SX PC. I had 20MB of the PC's 40MB Drive set up as a Macintosh Volume and could transfer shared files Mac<->PC at SCSI speeds. I had a JT-FAX card in the PC and would...

nexperia 74AVC16T245 TI SN74AVC16T245

https://www.ti.com/lit/gpn/tmux1208 https://www.ti.com/lit/ds/symlink/tmux1208.pdf?ts=1782493572672&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTMUX1208