ACT8937A
Rev 1, 22-Oct-12
completes the boot-up sequence.
interrupts the processor. In response to this
interrupt the processor should de-assert
PWREN(XPWRRGTON), disabling REG2, REG3,
REG4, REG6 and REG7. PWRHLD should remain
asserted during SLEEP mode so that REG1 and
REG5 remain enabled.
As with the enable sequence, a typical disable
sequence is initiated when the user presses the
push-button, which interrupts the processor via the
nPBSTAT output. The actual disable sequence is
completely software-controlled, but typically
involved initiating various “clean-up” processes
before the processor finally de-asserts PWRHLD to
disable the ACT8937A, and hence shuts the
system down.
Waking up from SLEEP mode is typically initiated
when the user presses the push-button again,
which enables REG2, REG3, REG4, REG6 and
REG7 and asserts nPBSTAT, which interrupts the
processor, the processors should respond by
asserting PWREN(XPWRRGTON), which holds
REG2, REG3, REG4, REG6 and REG7 so that
normal operation may resume. An external interrupt
, for instance a charger interrupt or a RTC interrupt,
can also initiate a wake up sequence. When an
external interrupt is sent to the processor, the
processor should response by getting itself ready to
wake up from SLEEP mode first, then assert
PWREN(XPWRRGTON), which enables REG2,
REG3, REG4, REG6 and REG7 so that the normal
operation may resume.
SLEEP/Wake-up Sequence
The ACT8937A supports Samsung S5PC100,
S5PC110 and S5PV210 processors’ SLEEP mode
operation. Once a successful power-up routine has
been completed, SLEEP mode may be initiated
through
a
variety of software-controlled
mechanisms.
SLEEP mode is typically initiated when the user
presses the push-button during normal operation.
Pressing the push-button asserts the nPBIN input,
which asserts the nPBSTAT output, which
Figure 3:
Enable (from push-button) / Disable Sequence
ꢀ: Applicable only for ACT8937AQJ2##, when CHGIN input voltage is connected, PWRHLD has to be asserted within 260ms.
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