www
.mcu.com.cn
42
/
239
Rev.
1.00
CMS80F731x Reference Manual
5.2
Power Supply Monitor Register LVDCON
The MCU comes with a power supply detection function. If the LVD module enable (LVDEN=1) is set and the voltage
monitoring point LVDSEL is set, when the power supply voltage drops below the LVD setpoint, an interrupt will be generated to
alert the user.
If the LVD module is enabled before hibernation, the hardware will not close the module circuit after entering hibernation,
and a software shutdown is required (LVDEN=0).
0xF690
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
LVDCON
LVDSEL3
LVDSEL2
LVDSEL1
LVDSEL0
LVDEN
--
LVDINTE
LVDINTF
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset value
0
0
0
0
0
0
0
0
Bit7~Bit4
LVDSEL<3:0>:
LVD voltage monitoring points;
0000=
2.00V;
1000=
2.
00V;
0001=
2.20V;
1001=
2.
00V;
0010=
2.00V;
1010=
3.70V;
0011=
2.40V;
1011=
2.
00V;
0100=
2.00V;
1100=
4.00V;
0101=
2.70V;
1101=
4.30V;
0110=
2.00V;
1110=
2.
00V;
0111=
3.
00V;
1111=
2.
00V.
Bit3
LVDEN:
LVD enable;
0=
Prohibited;
1=
Enable.
Bit2
--
Reserved, must be 0.
Bit1
LVDINTE:
LVD interrupt enable bit;
0=
LVD Interrupt disabled;
1=
LVD interrupt enablement.
Bit0
LVDINTF:
LVD interrupt flag bit;
0=
The supply voltage is higher than the monitoring voltage;
1=
The supply voltage is lower than the monitor voltage (software zero).
5.3
IDLE Idle Mode
In this mode, only the CPU clock source is turned off. As a result, peripheral functions such as timers, PWM, I2C
and clock
generators (HSI/crystal drivers) are still functioning in this state.
After the system enters idle mode, it can be woken up by any interrupt, enter the interrupt handler after waking, and continue
to perform the post-hibernation operation after the interrupt returns.
If idle mode is entered in the interrupt service program, the system can only be woken up by a higher priority interrupt.