HMS8132E/HMS81032TL
Nov. 2001 Ver 2.00
61
16.3 Low voltage detection mode
(1) Low voltage detection condition
An on board voltage comparator checks that VDD is at the
required level to ensure correct operation of the device. If
VDD is below a certain level, Low voltage detector forces
the device into low voltage detection mode.
(2) Low Voltage Detection Mode
There is no power consumption except stop current, stop
mode release function is disabled. All I/O port is config-
ured as input mode and Data memory is retained until volt-
age through external capacitor is worn out. In this mode,
all port can be selected with Pull-up resistor by Mask op-
tion. If there is no information on the Mask option sheet,
the default pull up option (all port connect to pull-up resis-
tor) is selected.
(3) Release of Low Voltage Detection Mode
Reset signal result from new battery (normally 3V) wakes
the low voltage detection mode and come into normal reset
state. It depends on user whether to execute RAM clear
routine or not
Figure 16-4 Timing Diagram of Reset
MAIN PROGRAM
Oscillator
(X
IN
pin)
?
?
FFFE FFFF
Stabilization Time
RESET
ADDRESS
DATA
1
2
3
4
5
6
7
?
?
Start
?
?
?
FE
?
ADL
ADH
OP
BUS
BUS
RESET Process Step
~~
~~
~~
~~
~~
~~
ADL and ADH are start addresses of interrupt service routine as vector contents.
Figure 16-5 Low Voltage vs Temperature
1.55
1.60
1.65
1.70
1.75
1.80
1.85
-25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
LVD(V)
Temperature (
°
C)
Содержание HMS81004E
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