289 6502 Chip Selector
289 : 6502 Chip Selector
- Author: Brandon Ashworth
- Description: Simple TT Project to select the different chips in Ben Eater's 6502 project.
- GitHub repository
- Open in 3D viewer
- Clock: 1000000 Hz
How it works
Given the clock and high 5 bits of the address bus on Ben Eater's beardboard 6502, select set the correct lines to enable the different devices.
How to test
- ROM_CS - Active Low
- RAM_CS - Active Low
- RAM_OE - Active Low
- PERIPH_CS - Active Low
- VIA_CS - Active High
- URAT_CS - Active High
- SID_CS - Active Low
| CLK | A11 | A12 | A13 | A14 | A15 | ROM_CS | RAM_CS | RAM_OE | PERIPH_CS | VIA_CS | URAT_CS | SID_CS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 1 |
| 1 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 |
| 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 1 |
| 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
| 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 1 |
| 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 |
| 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 |
| 0 | 1 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
External hardware
Ben Eater 6502 breaboard computer or LED bar graph.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | CLK | ROM_CS | |
| 1 | A11 | RAM_CS | |
| 2 | A12 | RAM_OE | |
| 3 | A13 | PERIPH_CS | |
| 4 | A14 | VIA_CS | |
| 5 | A15 | URAT_CS | |
| 6 | SID_CS | ||
| 7 |