cs4239 Cirrus Logic, Inc., cs4239 Datasheet - Page 27

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

face is disabled. The DIN/EEN bit is also the
Data In (DIN) signal to read back data from the
E
drain data line supporting DIN and DOUT;
therefore, to read the correct data, the DOUT bit
must be set to a one prior to performing a read
of the register. Otherwise, the data read back
from DIN/EEN will be all zeros. The E
data can then be read from the DIN/EEN bit.
The CLK bit timing is controlled by the host
software. This is the serial clock for the
E
is used to write/program the data out to the
E
quired on SDA because it is an open-drain
output. Use the guidelines in the specific
E
pull-up resistor (a typical value would be
3.3 k ).
Programming the E
DS253PP2
2
2
2
2
1. Configure Control I/O base address by one
Crystal IC
EEPROM
PROM. The SDA pin is a bi-directional open-
PROM output on the SCL pin. The DOUT bit
PROM. An external pull-up resistor is re-
PROM data sheet to select the value of the
of two methods: regular PnP cycle or Crystal
Key method.
a. The host can use the regular PnP cycle to
b. If the Crystal Key method is used:
program the logical device 2 I/O base ad-
dress, and then place the chip in the
wait_for_key_state
First, write to the AP, send the 32-byte
Crystal key.
Start
S 1 0 1 0 0 0 0 0 A 0 0 0 0 0 0 0 0 A S 1 0 1 0 0 0 0 1 A
2
Address
PROM:
Part
Write
Address
Bank
Figure 3. EEPROM Format
Acknowledge
2
PROM
Start
Address
Part
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.
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.
2. Refer to the specific data sheet for the
3. Send the E
2
2
PROM during initialization. Cirrus can pro-
PROMs through the Control logical device in-
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.
2
Read
PROM you are using for timing require-
2
Second, configure the Control I/O base
address by writing 15h, 02h, 47h, 01h,
20h, 33h, 01h, 79h to the AP.
PROM now contains the PnP resource
CrystalClear Portable ISA Audio System
Data
2
PROM data in successive bits to
Acknowledge
2
PROM resource data format.
TM
Data
A
2
PROM data sheet for-
Data
Acknowledge
No
1
CS4239
P
Stop
27