wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 67

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

Pre-Production
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DATA READBACK
AUXADC measured data is stored in register 7Ah, and can be retrieved by reading the register in the
usual manner (see AC-Link Interface section). Additionally, the data can also be passed to the
controller on one of the AC-Link time slots not used for audio functions.
The output data word of the AUX ADC interface consists of three parts:
If the data is being read back using the polling method, there are several ways to determine when a
measurement has finished:
Table 49 AUX ADC Data
To avoid losing data that has not yet been read, the WM9714L can delay overwriting register 7Ah
with new conversions until the old data has been read. This function is enabled using the WAIT bit. If
the SLEN bit is set to ‘1’, then the ADC data appears on the AC-Link slot selected by the SLT control
bits, as shown below. The Slot 0 ‘tag’ bit corresponding to the selected time slot is asserted
whenever there is new data on that slot.
7Ah
or
AC-Link slot
selected by
SLT
78h
REGISTER
ADDRESS
•
•
•
•
•
•
1 Unused bit (Ignore).
Output data from the AUX ADC (12 bits)
ADCSRC: 3 additional bits that indicate the source of the ADC data.
Reading back the POLL bit. If it has been reset to ‘0’, then the measurement has
finished.
Monitoring the ADA signal, see GPIO and interrupt section. ADA goes high after
every single conversion.
Reading back 7Ah until the new data appears
14:12
11:0
9
BIT
ADCSRC
ADCD
WAIT
LABEL
000
000h
0
DEFAULT
AUXADC Source
000 = No measurement
001 = Reserved
010 = Reserved
011 = Reserved
100 = COMP1/AUX1 measurement (pin 29)
101 = COMP2/AUX2 measurement (pin 30)
110 = AUX3 measurements (SPKVDD/3)
111 = AUX4 measurement (pin 12)
AUXADC Data (Read-only)
Bit 0 = LSB
Bit 11 = MSB
AUXADC Data Control
0 = Overwrite existing data in 7Ah with new
data
1 = Retain existing data in 7Ah until it is read
DESCRIPTION
PP, Rev 3.2, October 2008
WM9714L
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