cs4239 Cirrus Logic, Inc., cs4239 Datasheet - Page 96

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

APPENDIX B: DIFFERENCES BETWEEN THE CS423xB AND THE CS4239
This part is designed to be hardware backwards compatible with some CS423xB designs, primarily
motherboard applications. New drivers will be needed to support this part.
Hardware Pin Differences:
1. RFILT and LFILT capacitors are no longer needed and should be removed. On the CS4239, these
2. The external L/RLINE analog inputs are no longer supported. LLINE is now FLT3D and is used
3. The analog microphone inputs are now mono. LMIC is changed to MIC, and RMIC has been re-
4. Mono Out, MOUT, has been removed. The pin is redefined as APSEL and used to change the Ad-
5. VDF4 has been changed to IRQG - a seventh interrupt (typically used for INT 10). The default is
6. The Modem Logical Device has been removed. This includes MCS and MINT.
7. Support for an external synthesizer has been removed. This includes SCS and SINT.
8. The peripheral port has been removed. This includes XD<7:0>, XIOR, XIOW, XA<0:2>. CDROM
9. The hardware strap enable for the CDROM has been moved. CS423xB designs have a pulldown on
10. The DSP serial port is no longer supported as an option on the 2nd Joystick connector or on
11. The consumer IEC-958 (S/PDIF) output, supported on the CS4237B and CS4238B, has been re-
12. Only two modes of Hardware Volume Control are supported: 2-button, and 3-button with momen-
13. Pullup resistors for the Joystick buttons, Hardware Volume Control pins, and the MIDIN pin are
96
applications must now drive the ISA bus directly or through buffers.
XIOR. To support the CDROM interface on the CS4239, the pulldown must be moved to the
MCLK/SCLK pin. Also, to enable the alternate CDROM chip select pin ACDCS, a pulldown must
be added to pin SDOUT.
pins 4 through 7. The DSP port has moved to pins 1, 2, 3, 5 and is multiplexed with the CS9236
wavetable pins.
moved.
tary mute. In addition, a 10 nF capacitor to ground is required for switch debounce on the CS4239.
no longer required as they are internal to the CS4239.
pins are renamed FLTI and FLTO and should have a capacitor placed between them. They are used
for the Crystal 3D Sound circuitry. Not populating this capacitor will not have any adverse affects
on the part, but will result in non-optimum 3D Sound.
for the 3D Sound function. A 0.01 F capacitor should be placed between this pin and analog
ground. When external analog wavetable is desired, the AUX1 analog inputs should be used.
moved.
dress Port. APSEL has an internal pullup, setting the Address Port to 0x279 for backwards
compatibility.
disabled to provide backwards compatibility.
CrystalClear Portable ISA Audio System
TM
CS4239
DS253PP2