Digilent 410-044-10P-KIT Manuel d'utilisateur télécharger pdf (Page 31)

Spartan-3 Starter Kit Board User Guide www.xilinx.com 31

UG130 (v1.1) May 13, 2005 1-800-255-7778

Voltage Supply

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

http://panda.cs.ndsu.nodak.edu/~achapwes/PICmicro/mouse/mouse.html

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 in Figure 1-2,

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 270Ω series resistors on the PS/2 data and clock signals connected to the FPGA. See the

schematic in Figure A-7 for more details.

Table 6-5:

PS/2 Port Supply Voltage Options

PS/2 Port

Supply Voltage

Jumper JP2

Setting

3.3V

(DEFAULT)

JP2

3.3V

JP2

1 2 ... 26 27 28 29 30 31 32 33 34 35 36 ... 63 64

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Digilent 410-044-10P-KIT Manuel d'utilisateur Page 31