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Re: 10MHz, 12.5MHz and Beyond!

Posted: 07 Oct 2019, 11:11
by PurpleGirl
Potato Semiconductors only has a few of the logic chips used. I mention them since their chips run around the GHz range.

http://www.potatosemi.com/

It seems they only have the OR gates and a couple of different buffer chips that are used by the Gigatron. It seems that they have none that are used by the accumulator or the ALU. These seem to be where the bottleneck is.

Re: 10MHz, 12.5MHz and Beyond!

Posted: 07 Oct 2019, 13:52
by at67
I've been playing with this ROM for the last couple of days and wow, Gigatron12.5MHz here I come.

P.S. I don't get the truncated screen shown on real hardware and in other emulators on my emulation, is this something you solved in the ROM since those pictures were posted?

Re: 10MHz, 12.5MHz and Beyond!

Posted: 07 Oct 2019, 15:58
by marcelk
That ROM v3y hasn't changed. The programmed refresh rate is for 31.25 kHz at 12.5 MHz. So at that speed, shrink the displayed pixels...

Last week I tested it again on my 15 MHz system after soldering the last color resistors (I had ran out of 820 Ohms). But then I found the game controller doesn't register anything anymore, and the keyboard adapter can't keep up either: it was spitting out multiple keystrokes for every key pressed.

Re: 10MHz, 12.5MHz and Beyond!

Posted: 20 Oct 2019, 22:49
by bmwtcu
Hi Marcel, just so I understand... I know that Dave Jones worked on the 4-layer PCB, but is it possible to buy one from you? Thanks!

Re: 10MHz, 12.5MHz and Beyond!

Posted: 21 Oct 2019, 16:56
by marcelk
Simply drop us an email. We still have a few.