WM8325 Datasheet, PDF (48/254 Pages) Wolfson Microelectronics plc – Processor Power Management Subsystem

WM8325
ADDRESS
R16529 (4091h)
Clock Control 2
BIT
LABEL
15 XTAL_INH
13 XTAL_ENA
12 XTAL_BKUPE
NA
Table 16 Clocking Control
DEFAULT
0
0
1
Production Data
DESCRIPTION
Crystal Start-Up Inhibit
0 = Disabled
1 = Enabled
When XTAL_INH=0, the internal
RC oscillator will provide CLKOUT
until the crystal oscillator is valid.
When XTAL_INH=1, the ‘ON’
transition is inhibited until the
crystal oscillator is valid.
Crystal Oscillator Enable
0 = Disabled at all times
1 = Enabled in OFF, ON, SLEEP
states
(Note that the BACKUP behaviour
is determined by
XTAL_BKUPENA.)
This field can only be written to by
loading configuration settings from
OTP/ICE. In all other cases, this
field is Read Only.
Selects the RTC and 32.768kHz
oscillator in BACKUP state
0 = RTC unclocked in BACKUP
1 = RTC maintained in BACKUP
(Note that XTAL_ENA must also
be set if the RTC is to be
maintained in BACKUP)
13.2 CRYSTAL OSCILLATOR INTERRUPTS
The Crystal Oscillator (XTAL) is associated with two Interrupt event flags.
The XTAL_START_EINT interrupt is set if the crystal oscillator fails to start-up within a timeout period
of approximately 24 seconds.
The XTAL_TAMPER_EINT interrupt is set if the crystal oscillator is stopped unexpectedly (eg. due to
tampering). Note that this interrupt is only supported if the crystal oscillator has previously started up
successfully. The XTAL_TAMPER_EINT is also set if the crystal oscillator is re-started following an
unexpected interruption.
Each of these secondary interrupts triggers a primary Real Time Clock and Crystal Oscillator
Interrupt, RTC_INT (see Section 23). In the case of XTAL_START_EINT, this can be masked by
setting the mask bit(s) as described in Table 17.
ADDRESS
R16404
(4014h)
Interrupt Status
4
BIT
LABEL
7
XTAL_START_EINT
6
XTAL_TAMPER_EINT
R16412
(401Ch)
7
IM_XTAL_START_EINT
Interrupt Status
4 Mask
Table 17 Crystal Oscillator (XTAL) Interrupts
DESCRIPTION
Crystal Oscillator Start Failure interrupt
(Rising Edge triggered)
Note: Cleared when a ‘1’ is written.
Crystal Oscillator Tamper interrupt
(Rising and Falling Edge triggered)
Note: Cleared when a ‘1’ is written.
Interrupt mask.
0 = Do not mask interrupt.
1 = Mask interrupt.
Default value is 1 (masked)
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PD, February 2012, Rev 4.0
48