CS4239 Datasheet, PDF (23/98 Pages) Cirrus Logic – CrystalClear™ Portable ISA Audio System

CS4239
CrystalClear^TM Portable ISA Audio System
HW Config. Byte 5: ACDbase Address Length
Mask, Default = 00000000
D7 D6 D5 D4 D3 D2 D1 D0
res res res res res CM2 CM1 CM0
CM2-CM0
Address bit masks for the Alternate
CDROM address decode, ACDbase.
See the CDROM Interface section
for more details on ACDbase
000 - ACDCS low for 1 byte
001 - ACDCS low for 2 bytes
011 - ACDCS low for 4 bytes
111 - ACDCS low for 8 bytes
xxx - all others, RESERVED
HW Config. Byte 7: Misc. Configuration Bits,
Default = 10000000
D7 D6 D5 D4 D3 D2 D1 D0
IHCD rbc PKD CKD CK2D VCEN rbc
rbc
VCEN
Volume Control Enable. When set,
the UP, DOWN, and MUTE pins be-
come active and provide a hardware
master volume control.
CK2D
Crystal Key 2 disable. When set,
blocks the part from receiving the
2nd Crystal key.
CKD
Crystal Key disable. When set, blocks
the part from receiving the Crystal
key.
PKD
PnP Key disable. When set, blocks
the part from receiving the Plug-and-
Play key.
IHCD
Interrupt High - CDROM. When set,
CDINT is active high. When clear,
CDINT is active low.
HW Config. Byte 8: Global Configuration Byte,
Default = 10000000
D7 D6 D5 D4 D3 D2 D1 D0
IFM VCF1 rbc res WTEN rbc res res
WTEN
Wave\table Serial Port Enable. When
set, enables the CS9236 Single-
Chip Wavetable Music Synthesizer
serial port pins. This function is also
available in C8. NOTE: The DSP
SPE bit in I16 must be 0 for the
wavetable port to function.
VCF1
Hardware Volume Control Format.
This bit controls the format of the
hardware volume control pins UP,
DOWN, and MUTE. The volume con-
trol is enabled by setting VCEN in
the previous Hardware Configuration
byte. VCF1 is also available through
C8.
0 - MUTE is a momentary switch.
MUTE toggles between mute and
un-mute. Pressing the up or down
switch always un-mutes.
1 - MUTE is not used. Two button
volume control. Pressing the up
and down buttons simultaneously
causes the volume to mute.
Pressing up or down un-mutes.
IFM
Internal FM. When set, the internal
FM synthesizer is enabled. When
clear, FM is disabled.
HW Config. Byte 9: Code Base Byte,
Default = 00000101
D7 D6 D5 D4 D3 D2 D1 D0
CB7 CB6 CB5 CB4 CB3 CB2 CB1 CB0
CB7-CB0
Code Base Byte. Determines the code
base located in the E²PROM. If not
correct, the Firmware code after the
PnP resource data is not loaded.
0x05 - CS4239 E²PROM Load
0x06 - CS4239 Host Load
DS253PP2
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