cs4239 Cirrus Logic, Inc., cs4239 Datasheet - Page 57

• Manufacturer Part Number: cs4239
• Description: Crystalclear? Ortable Isa Audio System Logic
• Manufacturer: Cirrus Logic, Inc.

Two bits, JR1 and JR0, are located in the Con-
trol register space (CTRLbase+0) for defining
the speed of the Game Port Interface. Four dif-
ferent rates are software selectable for use with
various joysticks and to support older software
timing loops with aliasing (roll-over) problems.
DS253PP2
CRYSTAL
CODEC
JAB1
JBB1
JACX
JBCX
JBCY
JACY
JBB2
JAB2
MIDOUT
MIDIN
5.6 nF
2.2 k
Figure 5. Joystick Logic
5.6 nF
2.2 k
5.6 nF
2.2 k
The Game Port hardware interface consists of
8 pins that connect directly to the standard game
port connector. Buttons must have a 1000 pF ca-
pacitor to ground and have internal 20 k
pullups resistors. X/Y coordinates must have a
5.6 nF capacitor to ground and a 2.2 k
resistor to the appropriate joystick connector pin.
Figure 5 illustrates the schematic to the joystick
connector.
1 nF
5.6 nF
2.2 k
CrystalClear Portable ISA Audio System
VDF
1 nF
1 nF
TM
1 nF
15
10
11
13
14
12
1
9
2
3
4
5
6
7
8
CS4239
series
57