USB Control

The power of a personal computer can be leveraged to create pinball machine software with simple or complex rulesets, video sequences, and audio effects. The PC's audio output can be connected directly to a pinball machine, but interfacing to the machine's switch and driver circuits and to display elements such as a dot matrix display requires an interface card such as a P-ROC.

Hardware Implementation

The P-ROC has a type B USB connector allowing it to connect directly to a PC using a standard USB cable. The USB signalling protocol is handled by an FTDI FT245RL chip on the P-ROC. This chip buffers incoming data destined for the FPGA and outgoing data being sent back to the PC. For more information about the FT245RL chip, refer to its datasheet.

USB Drivers

FTDI provides a free, closed-source driver for the FT245RL chip called D2XX. P-ROCs have been verified to work successfully with Windows based systems using D2XX. Attempts to communicate with a P-ROC in Mac OS using D2XX have been unsuccessful due to an apparent bug in the Mac OS D2XX implementation.

A free, open-source driver called libFTDI is also available. P-ROCs have been verified to work successfully in Linux and Mac based systems using libFTDi.

USB Bandwidth

The P-ROC can send/receive approximately 1 MB of data each second, which is more than enough to exchange any information needed to control a pinball machine, including DMD animation information at frame rates exceeding 60 fps.