Production Data
WM9715L
REGISTER
ADDRESS
BIT
15
LABEL
DEFAULT
DESCRIPTION
Disables Crystal Oscillator
24h
PD15
PD14
PD13
PD12
PD11
PD10
PD9
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
Additional
power down
control
14
13
12
11
10
9
Disables left audio DAC
Disables right audio DAC
Disables left audio ADC
Disables right audio ADC
Disables MICBIAS
Disables left headphone mixer
Disables right headphone mixer
Disables speaker mixer
8
PD8
7
PD7
6
PD6
Disables MONO_OUT buffer (pin 33) and phone
mixer
5
4
3
2
1
0
PD5
PD4
PD3
PD2
PD1
PD0
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
0 (ON)
Disables OUT3 buffer (pin 37)
Disables headphone buffers (HPOUTL/R)
Disables speaker outputs (LOUT2, ROUT2)
Disables Line Input PGA (left and right) *
Disables Phone Input PGA *
Disables Mic Input PGA (left and right) *
Table 40 Extended Power Down Register (Additional to AC’97 Rev 2.2)
Note:
*When disabling a PGA, always ensure that it is muted first.
ADDITIONAL POWER MANAGEMENT:
•
•
AUXDAC: see “Auxiliary DAC” section. AUXDAC is OFF by default.
Touchpanel Interface: see “Controlling the Touchpanel Digitiser / Power Management”.
The touchpanel digitiser is OFF by default.
SLEEP MODE
Whenever the PR4 bit (reg. 26h) is set, the AC-Link interface is disabled, and the WM9715L is in
sleep mode. There is in fact a very large number of different sleep modes, depending on the other
control bits. For example, the low-power standby mode described below is a sleep mode. It is
desirable to use sleep modes whenever possible, as this will save power. The following functions do
not require a clock and can therefore operate in sleep mode:
•
•
•
•
Analogue-to-analogue audio (DACs and ADCs unused), e.g. phone call mode
Pen-down detection
Interrupts
Battery alarm / analogue comparators (but not battery measurement)
The WM9715L can awake from sleep mode as a result of
•
•
A warm reset on the AC-Link (according to the AC’97 specification)
An interrupt event such as pen-down, battery alarm, etc (if interrupt wake-up is enabled –
see “Interrupt Control” section)
PD Rev 4.0 December 2007
55
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
