SM89516B datasheet(42/49 Pages) SYNCMOS

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SM89516B

8-Bit Micro-controller

64KB Flash

& 1KB RAM embedded

Specifications subject to change without notice contact your sales representatives for the most recent information.

ISSFD-M087

Ver D SM89516B 08/07/2015

- 42 -

11. Power Management Unit

Power management unit serves two power management modes, Idle and Power Down, for the users to do power

saving function.

Mnemonic: PCON

Address: 87h

Reset

SMOD

GF1

GF0

IDLE

00h

GF1: General-purpose flag bit.

GF0: General-purpose flag bit.

PD: Power Down mode control bit. Setting this bit turning on the PD Mode.

PD bit is always read as 0

IDLE: Idle mode control bit. Setting this bit turning on the Idle Mode.

Idle bit is always read as 0

11.1 Idle mode

An instruction that sets PCON.0 causes that to be the last instruction executed before going into the idle mode, the

internal clock is gated off to the CPU but not to the interrupt, timer and serial port functions.

There are two ways to terminate the idle. Activation of any enabled interrupt will cause PCON.0 to be cleared by

hardware, terminating the idle mode. The interrupt will be serviced, and following RETI, the next instruction to be

executed will be the one following the instruction that put the device into idle. Another way to wake-up from idle is

to pull RESET high to generate internal hardware reset.

11.2 Power Down mode

An instruction that sets PCON.1 cause that to be the last instruction executed before going into the Power-Down

mode. In the power-down mode, the on-chip oscillator is stopped. The contents of on-chip RAM and SFRs are

maintained. Be carefully to keep RESET pin active for at least 10ms in order for a stable clock.

The SM89516B can be resumed from power-down state by RESET pin or external interrupt INT0/ INT1. When it is

woken-up by RESET, the program will execute from the address 0000H. When it is woken-up by INT0 or INT1, the

program will execute from the corresponding interrupt service routine.

To enable wake-up by external interrupt pins, the associated interrupt control register (EA, EX0/EX1) must be

configured correctly. Additionally, the control bit PDWUE in SCONF register must be enabled as well.

Mnemonic: SCONF

Address: BFh

Reset

WDR

PDWUE

OME

ALEI

02H

PDWUE: Power down wake-up enable bit.

Set 1 to enable wake-up from power-down state by external pin int0 or int1.

SM89516B Datasheet(PDF) 42 Page - SyncMOS Technologies,Inc

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