82C931 Datasheet, PDF (31/64 Pages) List of Unclassifed Manufacturers – Plug and Play Integrated Audio Controller

82C931
4.4 16-Bit Type F DMA Playback
The 82C931 supports the Type F DMA playback.
4.5 Modem Interface
The 82C931 includes the modem as a PnP logical device, as
well as interface pins to connect to a modem chipset. When
PnP is activated (931-AD Mode), the 82C931 provides the
resource configuration for the modem chipset, such as the
I/O address range and interrupt level.
The modem interface pins include pin 31 (MODEMCS#), pin
30 (MODEMINT), pin 25 (IRQ3), and pin 26 (IRQ4). To use
the modem interface, pin 31 (MODEM#) must be pulled
low. If a modem is connected with the 82C931, the joystick
port will provide support for one joystick only.
4.6 Push Button Volume Control
In silicon revision 1.0, two pins of the joystick interface can be
used as volume control push-buttons (pin 30 as volume
down, and pin 31 as volume up) so that the speaker volume
can be controlled through front panel buttons in desktop or
notebook PCs. Appropriate software drivers are needed to
enable this feature.
When the volume control feature is enabled, only one joystick
will be supported by the joystick port.
In silicon revision 1.1, the volume pins are additionally avail-
able in pins 28 and 29, as shown:
pin#31 & 29
Volume up
pin#30 & 28
Volume down
These two pins are active-low, edge-triggering and pulled up
internally. When the button is pressed and the corresponding
pin is activated, the register bits MCIR16[5:4] are set accord-
ingly. The software drivers poll these two bits periodically.
The scheme is as follows:
Buttons
MCIR[5:4]
Action required for the
(BUTUP:BUTDN) driver
Press UP button
10
increase the volume by
one step
Press Down button
01
decrease the volume by
one step
Press both Up &
Down button
11
mute
The register bits MCIR[5:4] will be cleared automatically after
they are read by the driver.
4.7 External Serial EEPROM
The 82C931 has the resource data and serial identifier
required by the PnP specification stored internally. If an OEM
customer wants to use a different resource data and serial
identifier to customize their application, an external EEPROM
can be used. To use an external EEPROM, pin 43
(EXTROM#) must be pulled low. This enables the resource
data and serial identifier to be read from the external
EEPROM instead of the 82C931’s internal storage.
The 82C931 provides a serial EEPROM interface that is com-
patible with devices from a number of vendors. A 512- byte
EEPROM is sufficient for information required by PnP. Pin 35
of the 82C931 provides the data clock for the EEPROM. Pin
36 provides data to the EEPROM, while pin 37 gets input
from the EEPROM.
4.8 Serial Audio Interface
When the 82C931 is implemented in MB mode, the SAIO
connector is coming from pins 25, 26, 30 and 31.
SCLK
FSYNC
(LRCLK)
SADI
SADO
931-MB mode
(no pull-down at pin#11)
pin#26
pin#25
pin#31
pin#30
931-AD mode
(pull-down at pin#11)
pin#21
pin#22
pin#19
pin#20
The 82C931's serial audio interface supports the following
formats:
• I²S-justified format (ZV port) and its variations.
• Sony format (short right-justified format, used by OPTi's
wavetable chip and the Philips TDA1311AT DAC).
• AT&T PCM codec T7525 compatible16-bit mono format.
Please refer to sections 4.8.6, ZV-Port I2S, 4.8.7, Advanced
Precision General Purpose Serial Port, 4.8.8, TDA1311 Ste-
reo Continuous Calibration, for the respective timing dia-
grams.
4.8.1 I²S-justified format and its variations
In the I²S-justified format (ZV-port), LRCLK is low for the left
channel, and high for the right channel. The left-channel MSB
is left-justified to the high-to-low LRCLK transition with a sin-
gle SCLK delay. SDATA could be SADI when the 931 is in
receive mode, and SADO when the 931 is in transmit mode.
The LRCLK period is programmable with a minimum of 32
SCLKs (MC22[4]). The following example assumes LRCLK
period is greater than 32 SCLKs. Please note that in ZV port,
there is one more signal MCLK defined but this is not needed
for the 931.
912-3000-035
Revision: 2.1
OPTi
®
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