Voltage supply – Digilent 410-044-10P-KIT User Manual
Page 31
Spartan-3 Starter Kit Board User Guide
31
UG130 (v1.1) May 13, 2005
1-800-255-7778
Voltage Supply
R
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.
The following site contains additional information on interfacing to a PS/2-style mouse:
•
The PS/2 Mouse Interface
Voltage Supply
Most modern keyboards and mice work equally well from a 3.3V or 5V supply. The voltage
supply for the PS/2 port is selectable via the JP2 jumper, indicated as
,
located immediately above the PS/2 connector along the right edge. The 3.3V setting is
preferred as the FPGA’s output signals operate from the 3.3V supply. The JP2 jumper
should be positioned as shown in
Table 6-5
by default.
Some older keyboards and mice are 5V only. Consequently, the JP2 jumper should be set
for 5V operation as shown in
Table 6-5
. The Spartan-3 FPGA can tolerate 5V signals due to
the 270
Ω series resistors on the PS/2 data and clock signals connected to the FPGA. See the
for more details.
Table 6-5:
PS/2 Port Supply Voltage Options
PS/2 Port
Supply Voltage
Jumper JP2
Setting
3.3V
(DEFAULT)
5V
30
JP2
3.3V
VU
3.3V
VU
JP2