HT46R51/HT46R52
EXIT_INT_ISR:
mov
mov
mov
reti
a,status_stack
STATUS,a
a,acc_stack
; restore STATUS from user defined memory
; restore ACC from user defined memory
Low Voltage Reset - LVR
The relationship between VDD and VLVR is shown below.
There is a low voltage reset circuit (LVR) implemented in
the microcontrollers. The function can be enabled/dis-
abled by options.
V
D
D
V
O P R
5
.
5
V
5
.
5
V
If the supply voltage of the device is within the range
0.9V~VLVR such as changing a battery, the LVR will au-
tomatically reset the device internally.
V
L
V
R
3
.
0
V
The LVR includes the following specifications:
2
.
2
V
·
The low voltage (0.9V~VLVR) has to remain in their
original state to exceed 1ms. If the low voltage state
does not exceed 1ms, the LVR will ignore it and do not
perform a reset function.
0
.
9
V
·
The LVR uses the ²OR² function with the external RES
signal to perform chip reset.
Note: VOPR is the voltage range for proper chip
operation at 4MHz system clock.
V
D
D
5
.
5
V
L
V
R
D
e
t
e
c
t
V
o
l
t
a
g
e
V
L
V
R
0
.
9
0
V
V
R
e
s
e
t
S
i
g
n
a
l
R
e
s
e
t
N
o
r
m
a
l
O
p
e
r
a
t
i
o
n
R
e
s
e
t
*
1
*
2
Low Voltage Reset
Note: *1: To make sure that the system oscillator has stabilized, the SST provides an extra delay of 1024 system
clock pulses before entering the normal operation.
*2: Since low voltage state has to be maintained in its original state for over 1ms, therefore after 1ms delay,
the device enters the reset mode.
Rev. 1.40
19
July 12, 2005
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
