This are RGB Pattern Generator projects designed for Arduino boards.
7 different patterns are provided:
- 8 colored vertical bars
- 8 colored vertical bars of first half part of screen then plain red shape second part
- 8 colored vertical bars of first half part of screen then plain green shape second part
- 8 colored vertical bars of first half part of screen then plain blue shape second part
- cross
- grid
- dots
This generator is designed for 15 KHz Arcade Monitors. It is based on 16 MHz Arduino boards like the Nano and the Uno ones (both have been tested).
Pure assembly source code is provided in 15khz_pattern_generator folder. Just clone this folder, open it with the Arduino IDE and you are ready to go.
Particular care is taken to provide accurate syncing timings, based to the information provided on the MS-2931 Monitor Service Manual, as described by @gc339 in a very detailled WIP on gamoover. Thanks to him!
- Line sync pulse is 4.75 µs long. It is followed by a 6.45 µs back porch, then take the line draing during 49.17µs. After that is a 3.19µs front porch before the next line sync line pulse.
- Frame sync pulse is 3 line long. After that, 23 empty lines (vertical back porch) are sent before sending the 224 lines of the displayed image. Then come 13 blank lines (vertical front porch), before the next image is going to be generated.
Arduino outputs can be be wired directly to the Monitor or, if you prefer, via a buffer (LS125, LS367, ...) in order to protect your Arduino. C.SYNC signal combines both vertical and horizontal sync signals on a sigle wire. With Arcade Monitors, the C.SYNC signal is enough. This is at least the case with the popular Hantarex ones.
You can select the pattern one by on with the pushbutton S1.
At this step of the development, ony two patterns are provided : 8 colors vertical bars and grid. More to come asap.
