wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 64

• Manufacturer Part Number: wm9714l
• Description: Ac?97 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

WM9714L
AUXILIARY ADC
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The WM9714L includes a very low power, 12-bit successive approximation type ADC which can be
used for battery and auxiliary measurements. Three pins that can be used as auxiliary ADC inputs:
Pins 29 and 30 are also used as comparator inputs (see “Battery Alarm and Analogue
Comparators”), but auxiliary measurements can still be taken on these pins at any time.
Additionally, the speaker supply (SPKVDD) can be used as an auxiliary ADC input through an on-
chip potential divider giving an input to the auxiliary ADC of SPKVDD/3. This input is referred to as
the AUX3 input.
Figure 24 Auxiliary ADC Inputs
The AUX ADC is accessed and controlled through the AC-Link interface.
AUXADC POWER MANAGEMENT
To save power, the AUXADC can be independently disabled when not used.
The AUXADC is powered-down using PADCPD, register 3Ch bit 15.
The state of the ADC is controlled by the following bits.
Table 46 AUXADC Power Management
3Ch
78h
REGISTER
ADDRESS
•
•
•
MIC2A / COMP1 / AUX1 (pin 29)
MIC2B / COMP2 / AUX2 (pin 30)
AUX4 (pin 12)
15
15:14
BIT
PADCPD
PRP
LABEL
1 = off
00
DEFAULT
AUXADC Disable Control
1 = Disabled
0 = Enabled
Additional Enable for AUXADC
00 = Disabled
01 = Reserved
10 = Reserved
11 = Enabled
DESCRIPTION
PP, Rev 3.2, October 2008
Pre-Production
64