Xilinx spartan-3a User Manual

Also see for Spartan-3A DSP FPGA Series: Datasheet User guide Getting started Technical reference guide User guide

Contents

Spartan-3A/3AN FPGA Starter Kit Board User Guidewww.xilinx.com 69UG334 (v1.1) June 19, 2008Voltage SupplyRThe magnitude of the X and Y values represents the rate of mouse movement. The largerthe value, the faster the mouse is moving. The XV and YV bits in the status byte indicatewhen the X or Y values exceed their maximum value, an overflow condition. A ‘1’indicates when an overflow occurs. If the mouse moves continuously, the 33-bittransmissions repeat every 50 ms or so.The L, R, and C fields in the status byte correspond to Left, Right, and Center buttonpresses. A ‘1’ indicates that the associated mouse button is being pressed.Voltage SupplyThe PS/2 port on the Spartan-3A/3AN Starter Kit board is powered by 5V. Although theSpartan-3A/3AN FPGA is not a 5V-tolerant device, it can communicate with a 5V deviceusing 270Ω series current-limiting resistors, as shown in Figure 8-1, page 65.Adding a Second PS/2 Port Using a Y-Splitter CableMost applications that use the PS/2 port will connect a mouse or a keyboard directly to theSpartan-3A/3AN Starter Kit board connector. These applications use the primary FPGAconnections to the PS/2 port, as shown in Figure 8-1, page 65.However, it is possible to include a second PS/2 port by connecting a PS/2 Y-splitter cableto the PS/2 connector on the board. Figure 8-6 shows an example of such a cable. TheSpartan-3A/3AN Starter Kit does not include such a cable but one can be purchased froma local electronics supply store or via the web. Some example vendors and part numbersare listed below. Check various vendors and suppliers as prices vary greatly!• StarTech PS/2 Keyboard/Mouse Y-splitter Cable, KYC1MF• American Power Conversion (APC) Mouse and Keyboard Splitter Cable, 62305-1• Belkin Pro Series Notebook Y Cable, F3G117-01• Tripp Lite, P230-001• QVS CC321Y• ComputerCableStore.com, 8-1718Y-00.5• CablesToGo, 08017When using the splitter cable, use both sets of FPGA connections listed in Figure 8-1,page 65 and Table 8-1, page 65. The primary connections appear at one side of theY-splitter while the secondary connections appear at the other side of the Y-splitter.Figure 8-6: Example PS/2 Y-Splitter CableUG330_c8_02_012507