An RGB composite sync signal generator for the Atari ST
This repository contains some verilog code to be synthesized and
programmed into a Lattice ICE40HX1K FPGA. The main target is
csync-predictive-prog; it programs the FPGA, to generate a clean RGB
composite sync signal from an Atari ST H-Sync and V-Sync signal. This
allows displaying the Atari ST video outout on any RGB compliant
display device.
Usage:
$ make csync-predictive-prod
Some other targets are also available (see Makefile), they have mostly been used to perform some experiments.
More context about this project can be found on my Generating a clean Atari ST RGB C-Sync signal article.
Prerequisites
The following Ubuntu / Debian packages are used:
- yosys
- arachne-pnr
- fpga-icestorm
- iverilog (optional)
- gtkwave (optional)
Lattice iCEstick pinout
J2 connector ports:
J2 pin | signal | FPGA pin
-------+---------+---------
1 | PIO1_02 | 78
2 | PIO1_03 | 79
3 | PIO1_04 | 80
4 | PIO1_05 | 81
5 | GND |
6 | +3.3V |
7 | PIO1_06 | 87
8 | PIO1_07 | 88
9 | PIO1_08 | 90
10 | PIO1_09 | 91
11 | GND |
12 | +3.3V |
Bottom of iCE40 FPGA stick:
+-------------+
|7. . . . . .12
|1. . . . . .6|
+-------------+
pin 1
+-----+
irda