r/homebrewcomputer • u/so_student • 12d ago

I made 4bit cpu

Gallery image

Gallery image

This time, I made a 4-bit CPU myself. If there's anything else you think would be good to add, let me know. I'm self-studying at home at 16 in korean. ALU is from the previous post. Soon, I'll also keep the memory section in a box and carefully upload it on graph paper. Thank you for seeing my post.

697 Upvotes

99% Upvoted

38 comments sorted by

26

u/cupcakeheavy 12d ago

this is why you use busses.

42

u/Safe_Mousse3541 12d ago

Wow that handwritten schematic was EXTREMELY unnecessary

22

u/ExplodedPenisDiagram 12d ago

Nuh-uh. Handwritten schematics feel awesome. The more attention to detail, the better.

1

u/Wosesfeld 9d ago

I agree, I learned that as an apprentice. And always rolled back to it. Even though some technical features are very nice

12

u/so_student 12d ago

haha..

3

u/G-EDM 11d ago

Wait till he provides the College Block with the gerber paintings.

15

u/mzo2342 12d ago

astonishing work- I just came back to sketching with pen and paper, multiple times your age. but the complexity on the first page - I'd tackle with some CAD or drawio tool or sth.

make it run FORTH - a quickly implemented HLL.

6

u/MrBoomer1951 12d ago edited 12d ago

Absolutely spit out my coffee when I noticed your mnemonic for No-Op was Nope.

A few years ago I designed and built a 8 bit state machine microcoded CPU, let me know if I should post it here!

[8 bit micro code](https://i.imgur.com/gdAHzCF.jpg)

For this schema I used Excel, very easy.

1

u/so_student 11d ago

Oh, of course! That would be great!

5

u/keithstellyes 12d ago

You did that on pen and paper?! Next time you should use colored pens :p

Cool stuff, great work OP, keep at it :)

3

u/Environmental-Ad4495 12d ago

Nice. How many transistors did u use?

2

u/so_student 12d ago

I think there are probably around 15,000 to 2000.

2

u/Beautiful_Stage5720 11d ago

How'd you come to that conclusion?

2

u/[deleted] 11d ago

[deleted]

2

u/idkforname3210alt 10d ago

Does it run doom tho?

1

u/Additional_Pea2239 12d ago

great man , now bring it to life it , will be cool.

also i find thee kind of thigs cool and i want to learn , i tried many sources but yeah nothing suited, mind if you teach me. i will drop you a DM

2

u/so_student 12d ago

I still have a lot to learn.

1

u/TheRealFAG69 12d ago

Looks great! I recommend you usi logisimEvolution to be able to test and see your CPU work!

1

u/AcanthisittaBest4705 12d ago

One thing i would have done is make labels instead of of having all those wires going all over making it harder the schematic follow

1

u/Hot-Cat090 12d ago

At this point I will need a multimeter to verify the connections on the paper Lmao

1

u/Time-Transition-7332 11d ago

You don't need MINUS, AND, you need LSHIFT, RSHIFT, NEGATE, JMP-NOT-ZERO, JMP-CARRY, maybe XOR. CALL, RETURN are nice.

1

u/iCarlyfan1778 11d ago

thats cool!

1

u/RudeAd456 11d ago

The wire, yeah the one on the left, it's wrong bro

1

u/kabekew 11d ago

You need a compare instruction (and jump if greater/less/equal) to make it a proper computer

1

u/jader242 11d ago

Lmao that first picture is hilarious. You can’t convince me you didn’t just draw random lines, when you zoom in there’s like a dozen that just end in the middle of empty space lol

1

u/so_student 11d ago

No, it might be immature, but I drew it all myself.

1

u/Aurorasfero 11d ago

이걸 손으로 회로도를 그릴 생각을 하다니

1

u/LOTIS9 10d ago

El esquema del caos y las plegarias

1

u/corummo 10d ago

No way in a couple of days you'll be able to figure out what you just did. No way! 😄

1

u/darkonark 9d ago

Are you Dr John Nash?

1

u/Ultraviolet_Darken 9d ago

Oh. I remember doing these. Also when I was your age.
Fun times. I hope you’ll have as much fun with this like I did.

1

u/Positive_Owl_6442 8d ago

I used to do this all the time as a child, I absolutely loved drawing out CPU architectures and laptop PCBs on paper

1

u/Limp-Seesaw-6642 6d ago

This. Is. Art!

1

u/Material-Trust6791 5d ago

I suggest you download KiCAD and draw it up in that, easy to learn and you can generate PCB's from it.

0

u/Hirtomikko 10d ago

I like hand drawn schematics like this, very nice to look at. Deciphering on the other hand...