Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [homebrew-cpu]

29 questions
31
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3 answers

Can you make a CPU out of electronic components drawn by hand on paper?

I explored a lot of literature about paper-based electronics recently, and one particular paper caught my interest: “Handwritten Oxide Electronics on Paper” (DOI: 10.1002/admt.201700009) by Elvira Fortunato et al. It explains a method to make…
Zoé Martin
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14
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FPGA CPUs, how to find the max speed?

I'm just getting into FPGAs, and if I understand correctly, you are connecting logic gates together using code. So if I design a CPU in Verilog, it should connect some logic gates together and work, but how do I know how fast my DIY CPU can run?…
user138530
8
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3 answers

Why are the SRAM data and address pins numbered?

As far as understand, it would make no difference to the operation of an SRAM if you mixed up the order of the address or data pins. E.g.…
fadedbee
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4
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3 answers

How to do signed 16-bit arithmetic on an 8-bit processor?

For example, to add two 16-bit numbers on my 8 bit machine, I add the low bytes together, then the high bytes together, and then add the carry flag to the high byte of the output. This strategy falls apart when dealing with twos complement signed…
Max Zabarka
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4
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1 answer

How to minimize microcode complexity in 8-bit home-brew CPU

tldr; I built and later extended Ben Eaters 8-bit breadboard computer. After the initial build I integrated 16-bit program counter and memory address registers, redesigned the instruction set and managed to access 64kB of RAM. Going forward I added…
Scott vanVoss
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4
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2 answers

Approaches to storing and addressing microcode for homebrew CPU

I've been teaching myself about CPU architecture for a while now and have successfully designed a couple myself. They were always based around microcode to drive the CPU's control lines. The microcode is stored on one ROM chip and addressed by…
Ruud van Falier
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4
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1 answer

Building a byte-addressable memory

I am building a memory module: 32 bits wide, parallel, and, byte-addressable. I did a research and i could not find an memory IC that will suit my needs. It must be able to: StoreWord, StoreHalf and, StoreByte (RISC-V), with or without an…
Kralik_011
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3
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Is there any computing system you can make yourself that you can connect to the internet?

Is there any computing system, kit or project where you would actually assemble components to form a rudimentary computer which could actually be used to send basic transmissions over the internet? In other words, something on a lower level than…
hmltn
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3
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3 answers

16-bit Byte-Addressable RAM Interface

I am a beginner to computer engineering and electrical engineering, and I have watched the entirety of Ben Eater's 8 bit breadboard computer series so I decided that because I understood that well, that I would try and design my own 16-bit CPU…
user140052
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2
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1 answer

What's the saturation speed of a transistor and the wires between inside a modern CPU?

I'm tinkering with a specialized CPU design and I'd like to calculate/estimate the saturation time of a circuit that may eventually be part of a CPU made with current technology. For this I need to know: How long do I need to provide signal to a…
Mikeologist
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Designing an instruction set for a homebrew computer

I'm going to begin the adventure of building an 8-bit homebrew computer. Right now, I'm considering the instruction set. SAP-1 seems a bit too sparse, so I'm designing my own. Some facts: My primary goal is to learn. I'll be building this on…
Peter
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2
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FPGA and CPU design: Moving from ideal memory to real RAM blocks

I implemented the single-cycle MIPS design from "Computer Organisation and Design" in Verilog, shown below: I used my own "ideal" data memory implementation, which asynchronously presents the read data on the output, and writes data on the rising…
keksmonster
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1 answer

Designing a Carry lookahead unit using EEPROMs, creates oscillator

I have read something about CLUs (Carry Lookahead Units) and want to build one. I have settled on a design using EEPROMS as adders and CLU. In the picture below, you can see a schematic CLU implementation. In my version, I think the best would be to…
Kralik_011
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2
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1 answer

What was the use-case for the 74hc590?

The 74hc590 http://www.ti.com/lit/ds/symlink/sn74hc590a.pdf is a binary counter followed by a register with a tri-state output. I thought about using it in a homebrew CPU design, as it's wider than the 74hc161, but the output buffer means that it…
fadedbee
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Should I build my own tri-state buffers?

I am attempting to build a simple CPU from only BJT transistors. It will have a bus so I will need some tri-state buffers. Can I/should I build them, or should I buy a chip? Is the risk of damaging the transistors with static electricity and sorts…
joupy
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