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 The Gigatron - a TTL CPU in 36 chips (plus memory) 
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1257
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It's a TTL CPU, using a modest number of TTL chips and all simple ones. Available as a kit too.

Video: Hack42 Lecture: The Gigatron by Walter Belgers and Marcel van Kervinck

From the project on hackaday.io:
Quote:
This is what we have now:
• 8-bits system built out of 1970s TTL chips (74LS)
• 34 TTL ICs, or 930 logic gates, for the CPU proper
• No microcontroller and no complex chips (such as the 74181 ALU)
• Only simple ICs, such as AND/OR, 4-bit adders, multiplexers, registers and so on
• 6.3 MHz. Might be pushed to 8 MHz
• 32kB 70ns RAM
• Harvard architecture with EPROM for program/data
• Operates on 2.5W, or below 0.5W for the 74HCT version
• RISC with pipelining: 1 instructions per clock (sometimes 2...)
• Instruction decoding with diodes
• Nice instruction set: ADD/SUB/AND/OR/XOR, conditional jumps, many useful addressing modes
• 60Hz 64 color VGA and 4 sound channels bit-banged from software
• Designed and built on a solderless breadboard in 6 weeks


Image

It can run a Mandelbrot demo, or a racer-style game, or a scroller-style game:

Image

Edit: see also this previous thread.


Fri Mar 23, 2018 1:56 pm
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Joined: Sat Mar 31, 2018 7:31 pm
Posts: 6
BigEd wrote:
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It's a TTL CPU, using a modest number of TTL chips and all simple ones. Available as a kit too.


Thanks Ed! Today is 1 year ago this project started with an empty breadboard, half an idea of how it might work, and a hand full of chips. Today strangers are building working Gigatrons :-)

Marcel


Sat Mar 31, 2018 8:09 pm
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1257
Welcome Marcel - very impressive project!


Sat Mar 31, 2018 9:22 pm
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Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1257
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Bit of a video review of the Gigatron kit here, with great praise for the manual:

Image


Sun Apr 22, 2018 10:20 am
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