WM9714L_06 WOLFSON [Wolfson Microelectronics plc], WM9714L_06 Datasheet - Page 54

• Manufacturer Part Number: WM9714L_06
• Description: AC 97 Audio CODEC
• Manufacturer: WOLFSON [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 auxillary ADC input through an on-
chip potential divider giving an input to the auxillary ADC of SPKVDD/3. This input is referred to as
the AUX3 input.
Figure 16 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
INITIATION OF MEASUREMENTS
The WM9714L ADC interface supports both polling routines and DMA (direct memory access) to
control the flow of data from the AUX ADC to the host CPU.
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
AUX ADC power down
Additional enable for AUXADC
00 – off
01 – NOT USED
10 – NOT USED
11 – on
DESCRIPTION
PP Rev 3.0 June 2006
Pre-Production
54