WM8351CGEB/RV WOLFSON [Wolfson Microelectronics plc], WM8351CGEB/RV Datasheet - Page 107

• Manufacturer Part Number: WM8351CGEB/RV
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
14.3 POWER SEQUENCING AND CONTROL
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14.3.1
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The start-up events are only valid provided also that the available supply voltage, sensed on the LINE
pin, is greater than the start-up threshold set by PCCMP_ON_THR, as defined in Section 18.
Start-Up by Wall adaptor plug-in occurs when the Wall Adapter feedback pin detects a voltage greater
than 4.0V. See Section 17.1 for a description of the WALL_FB pin function.
Start-Up by USB plug-in occurs when the USB voltage rises above the LINE voltage. If USB Suspend
mode is invoked, then USB plug-in starts the WM8351 on battery power, if available. When USB
Suspend Mode is not invoked, this start-up event will lead to starting the WM8351 on USB power, and
USB 100mA trickle charging of the battery is enabled.
Note that applying a battery voltage is not a start-up event, i.e. connecting a battery pack does not
start the WM8351. The WM8351 starts up on battery power if a startup event occurs and battery
power is the only power source available, provided the battery voltage is above the startup threshold.
(The start-up threshold is set by PCCMP_ON_THR, as defined in Section 18.)
In the ACTIVE state, the host processor can read the Interrupt status fields in Register R31 in order to
determine what action initiated the start-up. These fields indicate, for example, if the start-up was due
to a reset caused by an error condition, or if the start-up was caused by a PWR_ON input, or if the
start-up was caused by an RTC alarm. The first-level interrupt WKUP_INT is triggered whenever any
of the second-level interrupt events described in Table 56 is set. See Section 24 for further details of
Interrupt.
R31 (1Fh)
Comparator
Interrupt Status
The WM8351 moves from OFF or HIBERNATE states to the ACTIVE state when a startup event
occurs. Startup events include:
ADDRESS
A trigger signal on the ON pin lasting more than 40ms. The active polarity of this input is set by
the register field ON_POL.
A trigger signal on a GPIO pin configured as /WAKEUP lasting more than 40ms. The active
polarity of this input is set by GPn_CFG for the applicable GPIO pin (see Section 20).
A trigger signal on a GPIO pin configured as PWR_ON input lasting more than 40ms. The active
polarity of this input is set by GPn_CFG for the applicable GPIO pin (see Section 20).
Programmed ALARM from RTC module, if enabled (see Section 22).
Wall adaptor plug-in (WALL_FB rises above 4.0V).
USB plug-in (USB pin rises above 4.0V).
STARTUP
BIT
6
5
4
3
WKUP_OFF_STATE_EINT
WKUP_HIB_STATE_EINT
WKUP_CONV_FAULT_EINT
WKUP_WDOG_RST_EINT
LABEL
Indicates that the chip started from the
OFF state.
(Rising Edge triggered)
Note: This bit is cleared once read.
Indicated the chip started up from the
hibernate state.
(Rising Edge triggered)
Note: This bit is cleared once read.
Indicates the wakeup was caused by a
converter fault leading to the chip being
reset.
(Rising Edge triggered)
Note: This bit is cleared once read.
Indicates the wakeup was caused by a
watchdog heartbeat being missed, and
hence the chip being reset.
(Rising Edge triggered)
Note: This bit is cleared once read.
DESCRIPTION
PD, April 2012, Rev 4.5
WM8351
107