STAC9752 datasheet(59/95 Pages) IDT

59 / 95 page

STAC9752/9753

TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH HEADPHONE DRIVE, SPDIF OUTPUT MICROPHONE & JACK SENSING

IDT™

STAC9752/9753

REV 3.3 1206

TWO-CHANNEL, 20-BIT, AC’97 2.3 CODECS WITH HEADPHONE DRIVE, SPDIF OUTPUT MICROPHONE & JACK SENSING

8.1.18.1.

Ready Status

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.

Powerdown Controls

The STAC9752/9753 is capable of operating at reduced power when no activity is required. The

state of power down is controlled by the Powerdown Register (26h). See the section “Low Power

Modes” for more information.

8.1.18.3.

External Amplifier Power Down Control Output

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 0V 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: page77. The GPIO controls in Section 8.2:

page64 have no effect on EAPD.

8.1.19.

Extended Audio ID (28h)

Default: 0A05h

PR0

0 = ADC powered up

1 = ADC powered down

7:4

RESERVED

Bit not used, should read back 0

REF

Read Only --- VREF status

1 = VREFs enabled

ANL

Read Only ---- ANALOG MIXERS, etc. Status

1 = Analog Mixers ready.

DAC

Read Only ---- DAC Status

1 = DAC ready to playback

ADC

Read Only ---- ADC Status

1 = ADC ready to record

D15

D14

D13

D12

D11

D10

ID1

ID0

RESERVED

AMAP

RSVD

RESERVED

DSA1

DSA0

RSVD

SPDIF

RSVD

VRA

Bit(s)

Reset Value

Name

Description

STAC9752 Datasheet(PDF) 59 Page - Integrated Device Technology

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