Today i finished the new JAMMA-pcb. I will wait until tonight with my order since I usually remember something I have forgotten just after ordering. 😉
The PCB is designed to be connected to a Raspberry Pi 2 or the older model B with 40 pins I/O. All I/O-pins except CS1 is used. This was enough for 2 players each having joystick, 4 buttons and a start button each. Also coin and test are connected. However, you can use the board with any processor or system as long as they use 3.3V (or have level converters) and have a SPI bus.
I have also added sound. If I can get the FPGA doing what i want it will have 8-bit sound PWMed out of the very last free pin. If you want to use the FPGA sound you will loose a sprite (or maybe two, I’m not sure) since it needs a RAM block and at least 2k RAM. The PWM goes on to a double Butterworth filter (about 22kHz) to get rid of the PWM frequency (probably about 350kHz) that should be supressed by about 100dB by the filter. I added a 3.5mm plug to be able to connect to an external amp, or to connect to the on-board amp that follows the volume pot.
LOTS of things added, so I’m pretty sure something is not OK when the boards arrive. But that’s why they are called prototypes… 🙂