STC12LE5616AD datasheet(38/377 Pages) STC

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2.2 Power Management Modes

PCON register (Power Control Register)

SFR name Address

bit

PCON

87H

name

SMOD SMOD0 LVDF

POF

GF1

GF0

IDL

SMOD : Double baud rate of UART interface

Keep normal baud rate when the UART is used in mode 1,2 or 3.

Double baud rate bit when the UART is used in mode 1,2 or 3.

SMOD0 : SM0/FE bit select for SCON.7; setting this bit will set SCON.7 as Frame Error function. Clearing it to

set SCON.7 as one bit of UART mode selection bits.

LVDF

: Pin Low-Voltage Flag. Once low voltage condition is detected (VCC power is lower than LVD

voltage), it is set by hardware (and should be cleared by software).

POF

: Power-On flag. It is set by power-off-on action and can only cleared by software.

Practical application: if it is wanted to know which reset the MCU is used, see the following figure.

In initializtion program,

judge whether POF/PCON.4

have been set or not

POF=1,

Yes

cold boot

Power-On Reset

Clear POF/PCON.4

POF=0, No

external manual reset

or WDT reset

or software reset

or others

The STC12C5620AD core has three software programmable power management mode: slow-down, idle

and stop/power-down mode. The power

consumption of STC12C5620AD series is about 2.7mA~7mA in

normal operation, while it is lower than 0.1uA in stop/power-down mode and 1.8mA in idle mode.

Slow-down mode is controlled by clock divider register(CLK_DIV). Idle and stop/power-down is managed

by the corresponding bit in Power control (PCON) register which is shown in below.

GF1,GF0: General-purposed flag 1 and 0

Stop Mode/Power-Down Select bit..

Setting this bit will place the STC12C5620AD MCU in Stop/Power-Down mode. Stop/Power-Down

mode can be waked up by external interrupt. Because the MCU’ s internal oscillator stopped in Stop/

Power-Down mode, CPU, Timers, UARTs and so on stop to run, only external interrupt go on to work.

The following pins can wake up MCU from Stop/Power-Down mode: INT0/P3.2, INT1/P3.3, T0/P3.4,

T1/P3.5, RxD/P3.0, PCA0/PWM0/P3.7, PCA1/PWM1/P3.5, PCA2/PWM2/P2.0, PCA3/PWM3/P2.4.

IDL

: Idle mode select bit.

Setting this bit will place the STC12C5620AD in Idle mode. only CPU goes into Idle mode. (Shuts off clock to

CPU, but clock to Timers, Interrupts, Serial Ports, and Analog Peripherals are still active.) The following pins

can wake up MCU from Idle mode: INT0/P3.2, INT1/P3.3, T0/P3.4, T1/P3.5, RxD/P3.0. Besides, Timer0 and

Timer1 and UARTs interrupt also can wake up MCU from idle mode

STC12LE5616AD Datasheet(PDF) 38 Page - STCmicro Technology Co,.Ltd

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