WM9701 Wolfson Microelectronics plc, WM9701 Datasheet - Page 19

• Manufacturer Part Number: WM9701
• Description: Low Power AC97 Multimedia Audio Codec
• Manufacturer: Wolfson Microelectronics plc

Production Data
WOLFSON MICROELECTRONICS LTD.
Table 9 Power Down Control Register Function
Figure 12 An Example of WM9701A Power Down/Power up Flow
Figure 12 illustrates one example procedure to do a complete power down of WM9701A. From
normal operation sequential writes to the power down Register are performed to power down
WM9701A a piece at a time. After everything has been shut off, a final write (of PR4) can be
executed to shut down the WM9701A’s digital interface (AC-link).
The part will remain in sleep mode with all its registers holding their static values. To wake up
WM9701A, the AC’97 controller will send a pulse on the sync line issuing a warm reset. This will
restart WM9701A’s digital interface (resetting PR4 to 0). WM9701A can also be woken up with a
cold reset. A cold reset will cause a loss of values of the registers, as a cold reset will set them to
their default states. When a section is powered back on, the power down Control/Status register
(index 26h) should be read to verify that the section is ready (i.e. stable) before attempting any
operation that requires it.
Alternatively if RESETB is held low, all PR bits are held set so the device is held powered off until
RESETB is taken high again.
PR0
PR1
PR2
PR3
PR4
PR5
PR6
PR7
NORMAL
WRITE BIT
PR0 = 0 AND
ADC = 1
PR0 = 1
READY = 1
ADCs OFF
PR0
PR1 = 0 AND
DAC = 1
PCM in ADCs and input Mux power down
PCM out DACs power down
Analogue mixer power down (VREF still on)
Analogue mixer power down (VREF off)
Digital interface (AC-Link) power down (external clock off)
Internal clock disable
HP amp power down - not supported
Modem ADC/DAC off - not supported
PR1 = 1
DACs OFF
PR1
PR2 = 0 AND
ANL = 1
DEFAULT
PR2 = 1
OFF PR2 OR
ANALOGUE
PR3
FUNCTION
PR4 = 1
COLD RESET
DIGITAL I/F
OFF PR4
RESET
WARM
PD Rev 3.2 January 2001
WM9701A
CODA LINK
SHUT OFF
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