MicroBlaze Development Kit Spartan-3E 1600 Edition User Guide 67
UG257 (v1.1) December 5, 2007 www.xilinx.com
Voltage Supply
R
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-bit transmissions repeat
every 50 ms or so.
The L and R fields in the status byte indicate Left and Right button presses. A ‘1’ indicates
that the associated mouse button is being pressed.
Voltage Supply
The PS/2 port on the MicroBlaze Development Kit board is powered by 5V. Although the
Spartan-3E FPGA is not a 5V-tolerant device, it can communicate with a 5V device using
series current-limiting resistors, as shown in Figure 8-1.
UCF Location Constraints
Figure 8-6 provides the UCF constraints for the PS/2 port connecting, including the I/O
pin assignment and the I/O standard used.
Related Resources
x PS/2 Mouse/Keyboard Protocol
http://www.computer-engineering.org/ps2protocol/
x PS/2 Keyboard Interface
http://www.computer-engineering.org/ps2keyboard/
x PS/2 Mouse Interface
http://www.computer-engineering.org/ps2mouse/
Figure 8-6: UCF Location Constraints for PS/2 Port
NET "PS2_CLK" LOC = "G14" | IOSTANDARD = LVCMOS33 | DRIVE = 8 | SLEW = SLOW ;
NET "PS2_DATA" LOC = "G13" | IOSTANDARD = LVCMOS33 | DRIVE = 8 | SLEW = SLOW ;
U257_08_06_060506
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