HT48R70A-1 Holtek Semiconductor Inc, HT48R70A-1 Datasheet - Page 19

• Manufacturer Part Number: HT48R70A-1
• Description: I/O Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor Inc

Low Voltage Reset - LVR
The microcontroller provides low voltage reset circuit in
order to monitor the supply voltage of the device. If the
supply voltage of the device is within the range
0.9V~V
tomatically reset the device internally.
The LVR includes the following specifications:
Note:
Options
The following table shows all kinds of options in the microcontroller. All of the options must be defined to ensure proper
system functioning.
Rev. 1.60
The low voltage (0.9V~V
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.
The LVR uses the OR function with the external
RES signal to perform chip reset.
No.
10
1
2
3
4
5
6
7
8
9
LVR
*1: To make sure that the system oscillator has stabilized, the SST provides an extra delay of
*2: Since low voltage has to be maintained in its original state and exceed 1ms, therefore 1ms
, such as changing a battery, the LVR will au-
1024 system clock pulses before entering the normal operation.
delay enters the reset mode.
WDT clock source: WDT oscillator or f
CLRWDT instructions: 1 or 2 instructions
Timer/Event Counter 0 clock sources: f
Timer/Event Counter 1 clock sources: f
PA bit wake-up enable or disable
PA CMOS or Schmitt input
PA, PB, PC, PD, PE, PF, PG pull-high enable or disable (By port)
System oscillator
Ext. RC, Ext. crystal, Int. RC+RTC
Int. RC frequency selection 3.2MHz, 1.6MHz, 800kHz or 400kHz
LVR enable or disable
LVR
) has to remain in their
Low Voltage Reset
SYS
SYS
SYS
/4 or RTC oscillator or disable
/4 or RTCOSC
/4 or RTCOSC
19
Options
The relationship between V
Note:
V
tion at 4MHz system clock.
OPR
is the voltage range for proper chip opera-
HT48R70A-1/HT48C70-1
DD
and V
LVR
is shown below.
June 9, 2004