Gigatron Clone Ideas

Using, learning, programming and modding the Gigatron and anything related.
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alastair
Posts: 47
Joined: 10 Oct 2019, 14:28

Re: Gigatron Clone Ideas

Post by alastair »

Initial chip placement. The connectors and associated components haven't been added yet; they would go along the bottom edge. The gap is for the Pluggy Reloaded components. I left the option to use the existing Pierce Oscillator/6.25MHz crystal or you can use the can oscillator and divider (bottom left chip). The bottom right chip is for hi-res mode. I made room to install a 40-pin ZIF socket for the ROM. No video repeater though... I am thinking about adding headers to make it easy to install daughter cards for additional features/options. The board is designed to fit in a ZN-40 case. There's a power switch, but I still need to figure out where to put the blinken lights.
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alastair
Posts: 47
Joined: 10 Oct 2019, 14:28

Re: Gigatron Clone Ideas

Post by alastair »

Mostly routed. I was going to test the new design on a breadboard, but the only real change are the PALs. These can be reprogrammed so most of the debugging will be in firmware... assuming I didn't screw up the schematic. The ATtiny85 is on the board for the basic Pluggy, so it can be built to match the v2 Gigatron. I still plan to add the Pro Micro/SD Card on board for the Pluggy Reloaded option. 6-bit audio is standard with a single bi-color LED for a blinken light. Other options on board include the oscillator/divider for overclocking and 8 color hi-res mode with selector switch.
novatron.jpg
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bjchapm
Posts: 5
Joined: 23 Apr 2021, 23:05

Re: Gigatron Clone Ideas

Post by bjchapm »

This looks great. Very cool development.
bmwtcu
Posts: 122
Joined: 01 Nov 2018, 12:02

Re: Gigatron Clone Ideas

Post by bmwtcu »

alastair wrote: 14 May 2022, 03:45 ...the only real change are the PALs. These can be reprogrammed...
Very cool! I've only used GALs (which are reprogrammable) before, but I thought that PALs were OTP?
alastair
Posts: 47
Joined: 10 Oct 2019, 14:28

Re: Gigatron Clone Ideas

Post by alastair »

bmwtcu wrote: 17 May 2022, 16:03 I've only used GALs (which are reprogrammable) before, but I thought that PALs were OTP?
I usually use GALs, specifically the ATF16V8B for development. I try and stick within the original PAL specs so you could build it with the vintage parts. I do have some NOS PALs for another project, but I still need to recompile the JEDEC file so I can program them.
klf
Posts: 17
Joined: 10 Jan 2019, 22:48

Re: Gigatron Clone Ideas

Post by klf »

PAL16V8 is metal fuse PROM. GAL16V8 is EEPROM, HAL16V8 is mask ROM. 16V8 architecture is always the same.
alastair
Posts: 47
Joined: 10 Oct 2019, 14:28

Re: Gigatron Clone Ideas

Post by alastair »

Behold the "Novatron"! I forgot to order the ZIF socket of course... so I'll have to stop here until after the weekend. Clock is running and the program counter is counting.
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at67
Posts: 486
Joined: 14 May 2018, 08:29

Re: Gigatron Clone Ideas

Post by at67 »

Looks fantastic, well done!
alastair
Posts: 47
Joined: 10 Oct 2019, 14:28

Re: Gigatron Clone Ideas

Post by alastair »

Step one... enter the schematic correctly :roll:
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Sugarplum
Posts: 66
Joined: 30 Sep 2020, 22:19

Re: Gigatron Clone Ideas

Post by Sugarplum »

I recently thought of a different idea. Maybe if someone were to take 2 Gigatrons, use a 2-phase clock, and connect them at the memory. So let one do all the I/O and the other just run vCPU, and a somewhat simpler one due to not needing to care about time slices. The I/O one could handle video, sound, lights, keyboard, RNG, and external devices.

That is a different way to do it from what Marcel proposed.
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