WM8351CGEB/RV WOLFSON [Wolfson Microelectronics plc], WM8351CGEB/RV Datasheet - Page 169

• Manufacturer Part Number: WM8351CGEB/RV
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
19 AUXILIARY ADC
19.1 GENERAL DESCRIPTION
w
(GPIO Alternate function)
AUX1
AUX2
AUX3
AUX4
MASK
BATT
LINE
USB
The WM8351 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.
R12 (0Ch) Power
Mgmt (5)
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
ADDRESS
temperature
AUXADC_SCALEn
divide by 1,2,4
Voltage
Scaling
÷ 2
timing logic
BIT
AUXADC
15
7
AUXADC_ENA
LABEL
AUXADC_SEL1-8
select input
select reference (AUX1-4 only)
ADC
Aux
AGND
AUXADC_REFn
DEFAULT
0
To digital comparators
& readback registers
AUXADC control
0 = disabled
1 = enabled
VREF
VRTC
DESCRIPTION
PD, April 2012, Rev 4.5
ADA
(GPIO Alternate function)
WM8351
169