wm8350 Wolfson Microelectronics plc, wm8350 Datasheet - Page 108

• Manufacturer Part Number: wm8350
• Description: Wolfson Audioplus? Stereo Codec With Power Management
• Manufacturer: Wolfson Microelectronics plc

WM8350
14.3 POWER SEQUENCING AND CONTROL
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14.3.1
The WM8350 moves from OFF or HIBERNATE states to the ACTIVE state when a startup event
occurs. Startup events include:
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 WM8350 on battery power, if available. When
USB Suspend Mode is not invoked, this start-up event will lead to starting the WM8350 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 WM8350. The WM8350 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 55 is set. See Section 24 for further
details of Interrupt.
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STARTUP
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).
PD, June 2009, Rev 4.1
Production Data
108