22

DS308PP4

CS4281

CrystalClear™ PCI Audio Interface

CIRRUS LOGIC PRODUCT DATA SHEET

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.

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

39k

39k

10k

20k

5.1k

MMBT2907ALT1

MMBT3904LT1

MIDIOUT

3.3V

5V

MIDIOUT

(Buffered)

Joystick

Connector

Figure 11. MIDIOUT Buffer

+5 V

1nF

1

9

8

4

5

2

10

7

14

12

15

1nF

MIDIIN

MIDIOUT

JAB2

JBB2

JACY

JBCY

JBCX

JACX

JBB1

JAB1

3

11

13

6

1nF

1nF

12 nF

12 nF

12 nF

12 nF

2.2 k

Ω

2.2 k

Ω

2.2 k

Ω

2.2 k

Ω

4.7 k

Ω

4.7 k

Ω

4.7 k

Ω

4.7 k

Ω

4.7 k

Ω

CS4281

Figure 12. Joystick Logic