132 www.xilinx.com Spartan-3A/3AN Starter Kit Board User GuideUG334 (v1.0) May 28, 2007Chapter 15: Expansion Connectors RJ20 HeaderThe J20 header, shown in Figure 15-10, is the top-most six-pin connector along the rightedge of the board. It uses a female six-pin 90° socket. Four FPGA pins connect to the J20header, J20_IO<4:1>. The board supplies 3.3V to the accessory board mounted in the J20socket on the bottom pin.Digilent Peripheral ModulesDigilent Peripheral Modules (PMODs) are small I/O interface boards that offer an idealway to extend the capabilities of programmable logic and embedded control boards. Theyallow sensitive signal conditioning circuits and high-power drive circuits to be placedwhere they are most effective - near sensors and actuators. PMODs communicate withsystem boards using six-wire cables that can carry up to four digital control signals,including SPI and other serial protocols. PMODs allow more effective design partitions byrouting analog signals and power supplies only where they are needed and away fromdigital controller boards.• Digilent, Inc. Peripheral Moduleshttp://www.digilentinc.com/Products/Catalog.cfm?Cat=PeripheralFigure 15-10: FPGA Connections to the J20 Accessory HeaderJ20(V14) J20_IO1(V15) J20_IO2(W16) J20_IO3(V16) J20_IO4FPGAGND3.3VUG334_c15_10_052407
