https://github.com/gyurco/gstmcu
Simulation model of the Atari STE GSTMCU
https://github.com/gyurco/gstmcu
atari-st
Last synced: 5 months ago
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Simulation model of the Atari STE GSTMCU
- Host: GitHub
- URL: https://github.com/gyurco/gstmcu
- Owner: gyurco
- Created: 2019-04-25T13:45:06.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2025-01-02T23:14:34.000Z (over 1 year ago)
- Last Synced: 2025-02-01T11:29:26.966Z (over 1 year ago)
- Topics: atari-st
- Language: Verilog
- Size: 166 KB
- Stars: 8
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Atari STE GST MCU + GST Shifter
Simulation model of the Atari STE GSTMCU + Shifter
This repository contains a Verilog model of the Atari STE GST MCU (Glue + MMU combo).
The model tries to be an exact replica based on the [schematics recovered](https://www.chzsoft.de/asic-web/) by Christian Zietz.
The code contains both the identical gate-level circuits with asynchronous clocking, and a synchronous model hopefully suitable for FPGA synthesis.
There's a Shifter implementation, too, with both Video and Sound shifting. The core of the video shifter is based on the [reverse engineering](http://www.atari-forum.com/viewtopic.php?t=29658) work by Jorge Cwik.
# Testbench
The tb/ directory contains a testbench, which runs the circuits to generate waveforms for several frames. Also an rgb file is created using a RAM dump.
It requires Verilator for running the tests and generate the .vcd file, and ffmpeg to convert the .rgb output to .png.
To run the test:
```
cd tb
gzip -d stram.bin.gz
make
```
To see the genarated waveforms:
```
gtkwave gstmcu.vcd
```
To see a generated video frame:
```
make video
```
With the included RAM dump, the generated screen should look like:
