A Working 4-Bit Computer in Logisim? (It can play games)

Рет қаралды 277

6 күн бұрын

Why ain't there any good royalty free jazz on youtube?
This was a 2 week project I did from scratch last summer with 0 research but didn't have time to make a video for a year.
Logisim apparently does not like having to deal with 2000 logic gates all wired together in circuit spaghetti while trying to update at 4.1Khz
Specs:
RAM: 128 bytes (258 half-bytes)
ROM: 2 Kilobytes (4K half-bytes)
CPU: 4-bit, 1 core - 4.1KHz
Display: 15x15 monochrome custom serial display
CPU Instructions
0 - None
1 - Increase A(Accumulator)
2 - Decrease A
3 - Load number into A
4 - Add number to A
5 - Subtract number from A
6 - Left shift A
7 - Right shift A
8 - Load RAM address into A
9 - Store A into RAM address
A - Jump to ROM address
B - Compare A to number
C - Break jump on Equal
D - Break jump on Not Equal
E - Break jump on Less than
F - Break jump on Greater than
Music by me because I couldn't find any good royalty free jazz

Пікірлер: 10

@mke5 3 күн бұрын

Good vid

@AORA_INDUSTRIES 3 күн бұрын

Any tips on where to learn this? I have a good idea on how it works but doing this on such a low level logic (logic gates) seems hard

@uniprism 2 күн бұрын

I just looked at a couple videos about how computers work like this playlist by Sebastian Lague: kzbin.info/aero/PLFt_AvWsXl0dPhqVsKt1Ni_46ARyiCGSq. It also helps to have some programming knowledge for the low level logic part since you can just imagine the logic gates as a bunch of if statements. It mainly comes down to figuring out how to make smaller components, like binary adders and counters, and work yourself up to whatever your final goal is. Remember that google is your friend when looking for logic gate circuits.

@AORA_INDUSTRIES 2 күн бұрын

@@uniprism yeah I got ALUs and memory down pretty well but how did you manage to make a video card?

@uniprism 2 күн бұрын

@@AORA_INDUSTRIES It's basically 15 rows of 15-bit shift registers where one pixel can be updated at a time in the first column with the 4 bit input, and then the column of pixels is shifted to the next vertical line, so new pixels can be added to the first column again. Once the entire screen is ready, a single input can be used to update all of the pixels at once with another grid of 15x15 D flip-flops connected to the previous columns. So in total there are 15 initial D flip-flops connected to the 4-bit input and 30 D flip-flops per vertical line for the display, where one sets the value for the pixel and one updates the value to the screen. (This can be seen at 2:00)