WM8325
Production Data
The WM8325 monitors the DC-DC Converters and LDOs during the ON sequence to ensure that the
required circuits have powered up successfully before proceeding to the next timeslot. The nominal
timeslot durations are extended if necessary in order to wait for the selected DC-DC Converters or
LDOs to power up. If the ON sequence has not completed within 2 seconds of starting the transition,
then a Power Sequence Failure has occurred, resulting in the OFF state being forced.
The most recent ON or WAKE event can be determined by reading the bits in the “ON Source”
register, R400Eh. The most recent OFF event can be determined by reading the bits in the “OFF
Source” register, R400Fh.
The “ON Source” register is updated when a new ON event occurs. The “OFF Source” register is
updated when a new OFF event occurs. Note that some Reset conditions (see Section 24) result in
an OFF transition followed by an ON transition; these events are recorded as Reset events in the “ON
Source” register.
The ON Source and OFF Source register fields are defined in Table 2.
ADDRESS
BIT
LABEL
CHIP_ON
DEFAULT
DESCRIPTION
R16387
(4003h)
Indicates whether the system is
ON or OFF.
15
0
Power State
0 = OFF
1 = ON (or SLEEP)
OFF can be commanded by
writing CHIP_ON = 0.
Note that writing CHIP_ON = 1 is
not a valid ‘ON’ event, and will not
trigger an ON transition.
14
CHIP_SLP
0
Indicates whether the system is in
the SLEEP state.
0 = Not in SLEEP
1 = SLEEP
WAKE can be commanded by
writing CHIP_SLP = 0.
SLEEP can be commanded by
writing CHIP_SLP = 1.
PWRSTATE_DLY
Power State transition delay
00 = No delay
11:10
10
01 = No delay
10 = 1ms
11 = 10ms
R16398
(400Eh)
ON_TRANS
ON_GPIO
Most recent ON/WAKE event type
0 = WAKE transition
15
11
10
0
0
0
ON Source
1 = ON transition
Most recent ON/WAKE event type
0 = Not caused by GPIO input
1 = Caused by GPIO input
Most recent WAKE event type
0 = Not caused by PVDD
ON_SYSLO
1 = Caused by SYSLO threshold.
Note that the SYSLO threshold
cannot trigger an ON event.
ON_WDOG_TO
ON_SW_REQ
Most recent WAKE event type
0 = Not caused by Watchdog timer
1 = Caused by Watchdog timer
Most recent WAKE event type
0 = Not caused by software WAKE
7
6
0
0
1 = Caused by software WAKE
command (CHIP_SLP = 0)
PD, February 2012, Rev 4.0
34
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
