Digital I/O module
GPIO-MM PC/104 Diamond Systems

GPIO-MM is a PC/104 digital I/O module based on an FPGA, allowing multiple feature sets to be implemented on the same hardware platform. The FPGA is a Xilinx Spartan 2 RAM-based device with 200K gates (XC2S200). An on-board configuraton flash memory device stores the FPGA code for automatic loading on power-up, and new code can be downloaded using a JTAG cable connected to a PC. Several standard off the shelf personalities are available, and custom ones can be developed either by users with Xilinx tools or by Diamond as a customization service.

The right side I/O connector includes ESD protection circuitry for increased reliability, while the left side I/O connector offers high-drive logic buffers for increased load compatibility, along with jumper-configured pull-up / pull-down resistors. All digital I/O pins are set to input on power-up to avoid conflicts with external circuitry.

Hardware configuration options include jumper-selectable base address and DMA level, plus a 10-position jumper lock for user-definable field configurability when used with custom designs. A 256-byte EEPROM provides convenient non-volatile storage for user-defined functionality. The board also includes the layout for an optional RS-232/422/485 serial port, so that a multi-protocol serial port can be integrated into custom designs.