23 Power Monitoring Function
The MPC82G516A incorporates power monitoring functions designed to prevent incorrect operation during initial
power-up and power loss or reduction during operation. This is accomplished with two hardware functions:
Power-on Detection and Brownout Detection. Figure 23-1 shows the block diagram of power monitoring function.
Figure 23-1. Power Monitor Block Diagram
Inside the Chip
VDD
Low Drop-Out
Voltage Regulator
(LDO)
3.0V Output
V30
Power-on Detection
Brownout Detection
"1"
-
Input/Output
Buffer
Load
Comparator
VPOR(2.1V)
+
Power-on
Reset
POF
"1"
CPU Core,
RAM,
-
Load
Comparator
Flash,
ENLVRO
VOPF(3.7V)
+
Peripherals,
Glue Logic
OPF
"1"
Brownout
Reset
-
Load
Comparator
ENLVRC
VCPF (2.4V)
+
CPF
Note: ENLVRO and ENLVRC are the Hardware Options.
23.1 Power-on Detection
The POF flag (PCON.4) is set by hardware to indicate an initial power-up condition. It remains set until cleared by
software, and therefore helps the user to check if the start-running of the MCU comes from cold start (i.e., power
up) or warm start (such as hardware reset from RST pin, software reset or WDT reset). In addition to an initial
power-up condition, the POF flag will also be set by hardware whenever the VDD power falls below VPOR
.
PCON (Address=87H, Power Control Register, Reset Value=00xx,0000B (or 00x1,0000B after Power-On Reset))
7
6
5
-
4
3
2
1
0
SMOD SMOD0
POF
GF1
GF0
PD
IDL
POF: Power-ON Flag. This bit is set during power-on reset. It can also be set by software. However, it can only
be cleared by software.
115
MPC82G516A Data Sheet
MEGAWIN
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
