CS4281 Datasheet, PDF (22/36 Pages) Cirrus Logic – CrystalClear PCI Audio interface

CS4281
CrystalClear™ PCI Audio Interface
MIDI PORT
A bi-directional MIDI interface allows connection of external MIDI devices. The MIDI interface includes
a 16-byte FIFO for the MIDI receive path. A MIDI buffer (see Figure 11) is recommended due to some
joystick manufactures grounding the MIDIOUT pin.
MIDIOUT
CS4281
39k
39k
3.3V
MMBT2907ALT1
10k
5V
Joystick
Connector
5.1k
MIDIOUT
(Buffered)
20k
MMBT3904LT1
Figure 11. MIDIOUT Buffer
JOYSTICK PORT
The joystick port supports four “coordinate” channels and four “button” channels. The coordinate channels
provide joystick positional information to the host, and the button channels provide user button event in-
formation. The Joystick schematic is illustrated in Figure 12.
CS4281
+5 V
1
4.7 k Ω
4.7 k Ω
9
JAB1
2
JBB1
10
JACX
2.2 k Ω
3
JBCX
2.2 k Ω
11
12 nF
12 nF
1 nF
4
1 nF
12
JBCY
JACY
JBB2
JAB2
4.7 k Ω
MIDIOUT
4.7 k Ω ^{4.7 k Ω}
5
2.2 k Ω
13
2.2 k Ω
6
14
7
15
12 nF 12 nF ^{1 nF 1 nF}
8
MIDIIN
Figure 12. Joystick Logic
CIRRUS LOGIC PRODUCT DATA SHEET
22
DS308PP4