WM8352 datasheet(170/336 Pages) WOLFSON

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WM8352

Production Data

PD, February 2011, Rev 4.4

170

19 AUXILIARY ADC

19.1 GENERAL DESCRIPTION

The WM8352 incorporates a low-power 12-bit Auxiliary ADC (AUXADC). This can be used to

measure a number of internal or external voltages, with either VREF or VRTC as its reference. A

programmable potential divider enables the AUXADC to measure voltages higher than the reference.

Note that the AUX1 pin is also the input for the battery pack temperature monitoring circuit and is

therefore not freely available for other analogue inputs. The battery NTC input can still be sampled

and readback via AUX1 in the same way as the other AUXADC inputs. The AUX1 pin may be used

for other purposes if the NTC detection is disabled and/or the associated Battery Charger interrupts

are masked. See Section 17.7 for details of the battery pack NTC functions.

The AUXADC circuit is illustrated in Figure 78.

Figure 78 Auxiliary ADC

The AUXADC is enabled using the AUXADC_ENA register bit as described in Table 114.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R12 (0Ch) Power

Mgmt (5)

AUXADC_ENA

AUXADC control

0 = disabled

1 = enabled

R144 (90h)

Digitizer Control

(1)

Note: AUXADC_ENA can be accessed through R12 or through R144. Reading from or writing to

either register location has the same effect.

Table 114 AUXADC Enable

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