wm8350 Wolfson Microelectronics plc, wm8350 Datasheet - Page 175

• Manufacturer Part Number: wm8350
• Description: Wolfson Audioplus? Stereo Codec With Power Management
• Manufacturer: Wolfson Microelectronics plc

Production Data
19.3 VOLTAGE SCALING AND REFERENCES
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For inputs AUX1, AUX2, AUX3 and AUX4, the AUXADC measurements may be referenced to either
VRTC or VREF (see Section 21). The selected reference can be selected independently for each
input, using the control fields described in Table 115. In the case of USB, BATT, LINE and
Temperature, the AUXADC measurements are referenced to VRTC.
In the case of AUXADC measurements which are referenced to VREF, a buffered copy of VREF is
used as an input to the AUXADC. Setting the AUXADC_RBMODE field allows this buffer to be
enabled at all times when the AUXADC is enabled, or else to only be enabled when a VREF-
referenced measurement is made.
In order to measure voltages that may be higher than VRTC or VREF, a programmable divider is
provided on each of AUX1, AUX2, AUX3 and AUX4. These are controlled using the
AUXADC_SCALEn bits, allowing the inputs to be divided by 1, 2 or 4. In the case of USB, BATT and
LINE, a fixed ‘divide by 2’ applies.
R152 (98h)
AUX1
R153 (99h)
AUX2
R154 (9Ah)
AUX3
R155 (9Bh)
AUX4
R145 (91h)
Digitizer Control
(2)
Table 115 AUXADC Reference Selection
ADDRESS
14:13
BIT
12
1
AUXADC_SCAL
En [1:0]
AUXADC_REFn
AUXADC_RBM
ODE
LABEL
DEFAULT
11
1
1
AUXn input select
00 = Off
01 = Input divided by 1
10 = Input divided by 2
11 = Input divided by 4
AUXn reference select
0 = AUXn measured relative to
VRTC
1 = AUXn measured relative to
VREF
Enable for AUXADC bandgap
(VREF) buffer.
0 = AUXADC REFBUF is only
enabled during conversions that
use the VREF as a reference
1 = AUXADC REFBUF is always
enabled when the AUXADC is
enabled
DESCRIPTION
PD, June 2009, Rev 4.1
WM8350
175