SuperSoft HRx - Versuch eines Neubaus

Quote from AndyG

have the 9 inch hr-40 board which can be found on my Flickr account.

I only have one board (unlike the hr-40b) so am reluctant to remove IC’s …. though … I can photograph it in more detail as needed ….

Totally understand that you don't want to rip the ICs from it. But yea if you can make some nice pics from the underside and like - every side of the ics and maybe also keep a continuity tester in reach xD

HR80 is also figured out and the schematic is drawn.

The additional LS157 Multiplexer is used to double the pixels

Its 4 outputs are each connected (through some NANDs to allow mixing text and graphic) to 2 "neighboring datalines of the Charrom socket.

First, the Bit 0-3 from the RAM data are written out:

Bit 0 -> Charrom Bits 0 & 1

Bit 1 -> Charrom Bits 2 & 3

Bit 2 -> Charrom Bits 4 & 5

Bit 3 -> Charrom Bits 6 & 7

then the multiplexer switches to the upper bits, allowing the pet to draw the space of what would be the next character:

Bit 4 -> Charrom Bits 0 & 1

Bit 5 -> Charrom Bits 2 & 3

Bit 6 -> Charrom Bits 4 & 5

Bit 7 -> Charrom Bits 6 & 7

Btw. the latest version of the HR exhibition flyer talks about the existence of yet another version, the HR80PLUS, with 16K of Ram, allowing for a 640*200 output! Combined with the reported HR82 that makes 5 different HR graphics boards in total

Current state: HR40b and HR80 more or less done. I crated a github repository. Still private, as usual but if someone wants to look...

im starting to get behind the differences between the HR40 (non CRTC) and the HR40b (CRTC) board. identified the chips that are absent (most "CRT-related" as far as i get it)and trying to understand a bit more of everything.

I catched a flu and feel quite ill the last days, so no soldering yet on the data pecker, unfortunately.

thanks

in the meantime: what does that do? the video latch signal runs through this chain of inverters and the final nand stage, while on the non CRTC board the video latch signal is used directly. in both cases its then used to latch the graphic ram datalines onto the the charom datalines.

If i understand that correctly its delaying the transition from low to high and high to low?

only have to find out how they do the switching between chars and gfx on the 40 then the 40 shematics should be complete, too

Ja das wird's sein. Nochmal durchdacht, das erzeugt Pulse.

Generell meine ich, steht das HR40 (non CRTC) Schema

AndyG Could you do another pic of the area under the adapter socket?

Like from that angle (marked by the arrow)

And also maybe from the topside, from that angle:

That would be nice.

Thanks for that.

I think i have it boiled down to 4 questions that im 90% sure of should be okay.

Could you please check if these are true:

• IC7 Pin 2,3,8 and IC10 Pin5 are connected
• Blue clip wire (near IC10) and IC9 Pin 10 and IC6 Pin2 are connected
• IC 3 Pin3 and CHARROM-Adapter Pin 15 are connected
• Red clip wire (near IC4) and IC4 Pin 11 and the small trace under UD3 are connected

Unfortunately the HR40 has a multitude of traces and vias clearly going nowhere, which made it harder to identify the hidden traces.

But with these 4 questions answered, the card should be complete.

In the meantime, i built a bit more rugged solution to get to the CRTC datalines.

And then, there is this abomination xD

Quote from AndyG

The trace by UD3 where I tested was infant of the IC by the UDS label

This, I fear, I dont understand correctly. Can you describe it further?

Haha yea autocorrect made me say things i dont wanna type here xD

But that's great news, so everything turns out to be correct. And it makes sense in the schematic, too, as far as i can see (especially that long "dead" wire - its the VIDEO_LATCH signal from the pet. Goes directly in ICPin11 and should not go anywhere else. Maybe they intended to supply different possibilities of attaching the flyout wire.

NO WAIT... just checked that HR40b issue1 board you posted from the ebay auction - there you can see, they connected it on a universal board (i think) from UD1 Pin13 - that IS VIDEO_LATCH and also from UA2 Pin7, that is _CLK16 / CLK8 there. Both via diode and they a pulldown (?) - and that is on that seemingly nonsense Pin - oh.. can you please check if this lone thick trace is GND or +5V? Now i bet its 5V

With this.. next step would be a physical prototype of the HR40, HR40b and HR80 cards

Thanks. Makes more sense now, routing wise, too.

With this, as there is a german meme: "Ich habe fertig"

Cards are done. Now the proof lies in the pudding of building them.