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XY Register

A project log for 8 Bit Breadboard CPU

A home-brew 8 bit Microprocessor built on a breadboard 64K Address Space, IRQ, and DMA 16 Bit Stack Pointer, 4 8 bit Registers or 2 16 bit

2-Zons2-Zons 01/08/2019 at 04:374 Comments

Working on the XY register.  This is the register with the most control signals and features.  Separate hi, lo byte, and word increment and decrement.  Hi or lo byte in from or out to databus.  Word in from or out to Address bus (Address bus is used for 16 bit register to register transfers).   The address bus side of in and out is finished and tested.  Need to wire data bus in and out and lo byte to hi byte up down logic.  I've already used over 40' of wire just for this one register.  I'm going to need a lot more.  The yellow loops are control signals tied hi or lo for testing.  Dip switches are acting as the address bus.

Discussions

Dave's Dev Lab wrote 01/08/2019 at 05:55 point

nice work! i built some small LED modules for my SAP-1 build. i found it pretty useful instead of spending a lot of time on wiring up the LEDs on the breadboard. curious if you guys think it would be useful as well... https://hackaday.io/project/25597-daves-breadboard-led-trinket-blt

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2-Zons wrote 01/08/2019 at 06:18 point

Exactly what I need. As soon as I started working on it I realized I needed something like that. I'm planing on moving my LED board to each module as I build it for debugging. I'm planning to wire a place on each module where I can simply plug in a header so I don't have to individually wire it in each time. Your breadboard LED trinket would make life so much easier.

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Dave's Dev Lab wrote 01/08/2019 at 06:52 point

i can build up some for you, just let me know what colors, and if you want common cathode or common anode...

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Amos wrote 01/08/2019 at 05:28 point

The one thing I underestimated with my breadboard CPU build is the amount of wire I need. I'm waiting on an order of more spools so I can continue my build.

Keep up the good work.

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