cs4237b Cirrus Logic, Inc., cs4237b Datasheet - Page 26

• Manufacturer Part Number: cs4237b
• Description: Crystalclear Advanced Audio System With 3d Sound
• Manufacturer: Cirrus Logic, Inc.

specific E
of the pull-up resistor (a typical value would be
3.3k ).
Programming the E
The E
data. For this new data to take effect, the part
must be reset, causing the part to read the
E
vide a utility, RESOURCE.EXE, to program
E
terface.
26
1. Configure Control I/O base address by one
2. Refer to the specific data sheet for the
3. Send the E
2
2
PROM during initialization. Crystal can pro-
PROMs through the Control logical device in-
of two methods: regular PnP cycle or Crystal
Key method.
E
ments and data format. Also, refer to the
Loading Resource Data section of this data
sheet for the E
CTRLbase+1 (Hardware Control Register)
while following the E
mat.
a. The host can use the regular PnP cycle to
b. If the Crystal Key method is used:
2
PROM you are using for timing require-
program the logical device 2 I/O base ad-
dress, and then place the chip in the
wait_for_key_state
2
First, write to I/O 0279h, send the 32-
byte Crystal key. (The Crystal Key only
supports one Crystal part per system.)
Second, configure the Control I/O base
address by writing 15h, 02h, 47h, 01h,
20h, 33h, 01h, 79h to 0279h.
PROM now contains the PnP resource
2
PROM data sheet to select the value
2
PROM data in successive bits to
2
PROM resource data format.
2
PROM:
2
PROM data sheet for-
WINDOWS SOUND SYSTEM CODEC
The WSS Codec software interface consists of 4
I/O locations starting at the Plug and Play ad-
dress ’WSSbase’, and supports 12-bit address
decoding. If the upper address bits, SA12-SA15
are used, they must be 0 to decode a valid ad-
dress. The WSS Codec also requires one
interrupt and one or preferably two DMA chan-
nels, one for playback and one for capture. Since
the WSS Codec and Sound Blaster device are
mutually exclusive, the two devices share the
same interrupt and DMA playback channel.
The WSS Codec/Mixer is register compatible
with the Microsoft Windows Sound System.
Functions include stereo Analog-to-Digital and
Digital-to-Analog converters (ADCs and DACs),
analog mixing, anti-aliasing and reconstruction
filters, line and microphone level inputs, optional
A-Law/ -Law coding, simultaneous capture and
playback (at independent sample frequencies)
and a parallel bus interface. Five analog inputs
are provided and four can be mixed to the ADC
mixer. All five can be mixed with the output of
the DAC with full volume control. Several data
modes are supported including 8- and 16-bit lin-
ear as well as 8-bit companded, 4-bit ADPCM
compressed, and 16-bit big Endian.
Enhanced Functions (MODEs)
The initial state is labeled MODE 1 and forces
the part to appear as a CS4248. The more popu-
lar second mode, MODE 2, forces the part to
appear as a CS4231 super set and is compatible
with the CS4232. To switch from MODE 1 to
MODE 2, the CMS1,0 bits, in the MODE and
ID register (I12), should be set to 10 respec-
tively. When MODE 2 is selected, the bit IA4 in
the Index Address register (R0) will be decoded
as a valid index pointer providing 16 additional
registers and increased functionality over the
CS4248.
To reverse the procedure, set the CMS1,0 bits to
00 and the part will resume operation in
CS4237B
DS213PP4