sh6636 SinoWealth Micro-Electronics Corp. Ltd, sh6636 Datasheet - Page 12

• Manufacturer Part Number: sh6636
• Description: Mask 4-bit Microcontroller With Remote Control Carrier Synthesizer
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

11. Low Power Detection (LPD)
The LPD function is to monitor the supply voltage and applies an internal reset in the microcontroller at the time of battery
replacement. If the applied circuit satisfies the following conditions, the LPD can be incorporated by the software control.
High reliability is not required.
Power supply voltage V
Operating ambient temperature T
(a) Functions of the LPD Circuit:
The LPD circuit has the following functions:
Generates an internal reset signal when V
Cancels the internal reset signal when V
Stops the oscillator operation and forces the CPU to enter STOP mode when V
Here, V
V
reset will delay about 1ms to be triggered. If V
(b) LPD Control Register
LPDX
Address
Reset
V
V
LPD
2.5V
LPDH
LPDL
3.6V
$15
V
DD
is always in range of CPU operating, so there is no malfunction existing when V
DD
: power supply voltage, V
LPD3
Bit3
DD
= 2.2 to 3.6 V
LPD2
Bit2
A
= -20 C to + 70 C
LPDL
1ms
: POWER DOWN LPD-detect voltage, V
DD
LPD1
Bit1
DD
V
DD
LPDH
V
LPDL
goes back to V
.
.
LPD0
Bit0
12
DD
R/W
W
V
LPDH,
without any delay then cancel the LPD reset.
LPD Enable Control (LPD3 - 0):
0101: LPD Enable (Power-on initial)
1010: LPD Disable
DD
LPDH
V
: Power rise LPD-detect voltage.
LPDX
LPDL
.
is reached. As V
Remark
DD
V
LPDL,
SH6636
the LPD