Application Notes

[Steve Crompton]

Hi there,

Anyone here got any good sources for old manufacturers application notes

I am looking for Hitachi Application Note #U90

Hitachi HD63484 ACRTC Advanced CRT Controller Application Note

I have Googled it but only found a copy for sale at $75 - too much $$)

Regards

Steve

[Mark T]

Bitsavers has the user manual

https://archive.org/details/bitsavers_hitachidatitachi1984_10286622/page/n1

Mark

[Steve Crompton]

Hi Mark,

Yes unfortunately that's not the application note I am looking for - I have that one, I want #90 I believe that one is #75

[Marten Feldtmann]

Did you have luck in finding it ?

Marten

[Steve Crompton]

No Marten

Its annoying because I had a whole set (I think there were 3 Hitachi Manuals) on the 63484 ACRTC  - one of which contained detailed schematic ideas of various hardware configurations (video ram, dot shifters examples etc. for various colour depth and resolutions.) but alas the books I had seem to have got lost after a few house moves and garage clearances. The actual databook is hard going I find but the manual I am missing was so useful. I actually built a ACRTC monochrome system many many years ago for Z80 MSX but threw it out as a boys project not needed anymore when I progressed to PC's but now I want to do something retro again with what parts I still have and connect it to my retro 68K system I have built.

[Dave White]

I have a bunch of those chips and have been searching for the same application note for a year or more - too many hours searching with no luck st all.

[Alan Cox]

On Tuesday, 18 February 2020 18:45:54 UTC, Dave White wrote:

I have a bunch of those chips and have been searching for the same application note for a year or more - too many hours searching with no luck st all.

Have you tried InnovASIC because they produced a clone  (IA63484) to provide parts to folks stuck with life expired designs (I assume the US government .. it's usually the US government 8)).

http://www.bitsavers.org/pdf/eltec/ELTEC_PIG1_68K_May86.pdf also looks useful. The ELTEC PIG1 is a VMEBUS 63484 and it happens it include a circuit diagram. There a couple of PALs in there without equations but otherwise it's all 74F and 74LS.

Alan

[Alan Cox]

Interesting to see that Steve Ciarcia designed one in Byte too, presumably from whatever reference design has gone walkies.

https://archive.org/stream/byte-magazine-1986-11/1986_11_BYTE_11-12_Knowledge_Representation#page/n117/mode/2up

https://archive.org/details/byte-magazine-1986-12/page/n97/mode/2up

[Marten Feldtmann]

Yes, this is the GT180 board:

11/86 introduces the base technology

12/86 introduces the hardware

01/87 introduces the software aspects

For my design I copied lots of the design from them. I have still some questions open:

* They use a color palette which outputs max 0.7V peak ... and for VGAI need 1V, but I assume, I can change the output via changing the resistor values.

And a more principle question is:

All these additional chips from HD (63485 and 63486) seems to be limited to 64MHz pixel rate, but one can read, that these chips can be used for general large resolutions solutions. With 64Mhz you are somewhere in the area of 800x600 or 1024x768 - but I would like to be in the area of 1280x1024 and this needs around 100 Mhz.

I think I misunderstand some concepts here ?

[Steve Crompton]

I have all the parts to build a GT180 clone - what I don't have right now is the time sadly. It will make a great addition to my 68K system - one day eh

How far have you got so far?

[Alan Cox]

All these additional chips from HD (63485 and 63486) seems to be limited to 64MHz pixel rate, but one can read, that these chips can be used for general large resolutions solutions. With 64Mhz you are somewhere in the area of 800x600 or 1024x768 - but I would like to be in the area of 1280x1024 and this needs around 100 Mhz.

I think I misunderstand some concepts here ?

For one old multiscan displays did not run at VGA speed but rather slower. Many of the old 'high resolution' displays had long persist phosphor and lower update rates. The move to 75Hz or so is relatively modern driven by a mix of health and safety and ergonomics. 30Hz was not uncommon for specialist high resolution displays, some very high resolution displays went down even lower. 1024x1024 was also close to the upper limit people got. Even that often involved ECL shift registers on the output.

(And it's not without reason if you've ever watched a Sun3 trying to update a large mono unaccelerated display even with a decent 680x0 CPU!)

Today I guess you could run the thing at 1280x1024 interlaced to get the same effect (and maybe run it through an Amiga flicker fixer or similar into a modern display)

[Rob Gowin]

I found a paper copy of the U90 app note, have scanned it, and now it is available at Bitsavers.

http://www.bitsavers.org/components/hitachi/_dataBooks/U90_Hitachi_HD63484_ACRTC_Advanced_CRT_Controller_Application_Note_198604.pdf

-- Rob