584 4-Bit Counter and Registers Demo
584 : 4-Bit Counter and Registers Demo
- Author: Thomas Fischbacher
- Description: Educational Wokwi Demo
- GitHub repository
- Open in 3D viewer
- View in Wokwi
- Clock: 10000000 Hz
How it works
This is mostly an educational placeholder wokwi project, intended as a starting point for Swiss high school students to get going with their own designs.
The idea is to allow them to understand some ASIC design and digital circuitry basics by showing some ideas and design elements they might want to use in their own designs - and also discussing some pitfalls to avoid.
Wokwi URL: https://wokwi.com/projects/459285910800527361
The description on the Wokwi page contains some exercises for students to go through.
How to test
The circuit consists of two parts - a simple 4-bit binary counter, plus logic to store data in two 4-bit "registers" and retrieve it from there. The Wokwi project page has details.
As a brief summary:
-
Output pins C0,C1,C2,C3 simply cyclically count through 0000-1111, one step per clock cycle.
-
The outputs on pins DO0,DO1,DO2,DO3 can be made to show the value of either of two "4-bit registers" as follows:
- Setting (OP0,OP1,OP2) to (0,1,1) makes internal register A store the value available on DI0-DI3.
- Setting (OP0,OP1,OP2) to (1,1,0) makes internal register B store the value available on DI0-DI3.
- Setting (OP0,OP1,OP2) to (1,1,1) makes the outpot DO0-DO3 show the value of register A if SEL0 is 0, else the value of register B.
- If (OP0,OP1,OP2) is not (1,1,1), then DO0-DO3 are all 0.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | OP0 | C0 | |
| 1 | OP1 | C1 | |
| 2 | OP2 | C2 | |
| 3 | DI0 | C3 | |
| 4 | DI1 | DO0 | |
| 5 | DI2 | DO1 | |
| 6 | DI3 | DO2 | |
| 7 | SEL0 | DO3 |