VR4102 datasheet(321/701 Pages) NEC

321 / 701 page

CHAPTER 15 PMU (POWER MANAGEMENT UNIT)

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15.1.3 Power-on Control

The causes of CPU activation (mode change from shutdown mode or Hibernate mode to Fullspeed mode) are

called power-on factors. There are twelve power-on factors: a power switch interrupt (POWER), eight types of

GPIO activation interrupts (GPIO[12:9], GPIO[3..0]), a DCD interrupt (DCD#), a touch panel interrupt, and an alarm

interrupt.

Battery low detection is a factor that prevents CPU activation.

(1) Activation via Power Switch Interrupt

When the POWER signal is asserted, the PMU asserts the POWERON signal and provides external notification

that the CPU is being activated. After asserting the POWERON signal, the PMU checks the BATTINH signal and

then de-asserts the POWERON signal.

If the BATTINH/BATTINT# signal is high (“1”), the PMU cancels peripheral unit reset, then starts the Cold Reset

sequence to activate the CPU core.

If the BATTINH/BATTINT# signal is low (“0”), the PMU sets “1” to PMUINTREG’s BATTINH bit and then performs

another shutdown. After the CPU is restarted, the BATTINH bit must be checked and cleared (to “0”) by software.

Figure 15-1. Activation via Power Switch Interrupt (BATTINH/BATTINT# = 1)

BATTINH/

BATTINT# (i)

MPOWER(o)

POWERON(o)

POWER(i)

RTC(Internal)