STAC9766 IDT [Integrated Device Technology], STAC9766 Datasheet - Page 59

• Manufacturer Part Number: STAC9766
• Manufacturer: IDT [Integrated Device Technology]

IDT™
TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING
STAC9766/9767
TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH STEREO MICROPHONE AND MIC/JACK SENSING
8.1.19.
Bit(s)
1
0
D15
ID1
D7
8.1.18.1.
The lower half of this register is read only status, a 1 indicating that each subsection is “ready”.
Ready is defined as the subsection's ability to perform in its nominal state. When this register is writ-
ten, the bit values that come in on AC-Link will have no effect on read only bits 0-7.
When the AC-Link “CODEC Ready” indicator bit (SDATA_IN slot 0, bit 15) is a 1, it indicates that the
AC-Link and AC'97 control and status registers are in a fully operational state. The AC'97 controller
must further probe this Powerdown Control/Status Register to determine exactly which subsections,
if any, are ready. When this register is written, the bit values that come in on AC-Link will have no
effect on read only bits 0-7.
8.1.18.2.
The STAC9766/9767 is capable of operating at reduced power when no activity is required. The
power-down state is controlled by the Powerdown Register (26h). See the section “Low Power
Modes” for more information.
8.1.18.3.
The EAPD bit 15 of the Powerdown Control/Status Register (Index 26h) directly controls the output
of the EAPD output, pin 45, and produces a logical 1 when this bit is set to logic high. This function is
used to control an external audio amplifier power down. EAPD = 0 places approximately 0 V on the
output pin, enabling an external audio amplifier. EAPD = 1 places approximately DVdd on the output
pin, disabling the external audio amplifier. Audio amplifiers that operate with reverse polarity will
likely require an external inverter to maintain software driver compatibility.
EAPD can also act as a GPIO. See Section 8.4.11: page78. The GPIO controls in Section 8.2:
page65 have no effect on EAPD.
Extended Audio ID (28h)
Default: 0A05h
The Extended Audio ID register is a read only register except for bits D4 and D5. ID1 and ID0 echo
the configuration of the CODEC as defined by the programming of pins 45 and 46 externally. The
primary CODEC returns 00, while any other code (01, 10, 11) identifies the CODEC as one of three
secondary CODEC possibilities. The AMAP bit, D9, will return a 1 indicating that the CODEC sup-
RESERVED
Reset Value
1
1
D14
ID0
Ready Status
Powerdown Controls
External Amplifier Power Down Control Output
D6
Name
DAC
ADC
DSA1
D13
D5
Read Only ---- DAC Status
1 = DAC ready to playback
Read Only ---- ADC Status
1 = ADC ready to record
DSA0
D12
59
D4
RESERVED
RESVD
D11
D3
Description
STAC9766/9767
SPDIF
D10
D2
AMAP
RSVD
D9
D1
PC AUDIO
RSVD
VRA
V 7.4 12/06
D8
D0