HT46R48 Просмотр технического описания (PDF) - Holtek Semiconductor
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HT46R48 Datasheet PDF : 42 Pages
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HT46R48
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~3.3V, such as changing a battery, the LVR will au-
tomatically reset the device internally.
The LVR includes the following specifications:
· 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.
· The LVR uses the ²OR² function with the external RES
signal to perform chip reset.
V DD
5 .5 V
The relationship between VDD and VLVR is shown below.
V DD
V O PR
5 .5 V 5 .5 V
V LV R
3 .0 V
2 .2 V
Note:
0 .9 V
VOPR is the voltage range for proper chip
operation at 4MHz system clock.
V LV R
0 .9 V
0V
R e s e t S ig n a l
L V R D e te c t V o lta g e
R eset
N o r m a l O p e r a tio n
R eset
*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 the low voltage has to maintain in its original state and exceed 1ms, therefore 1ms delay enter the
reset mode.
Options
The following table shows all kinds of options in the microcontroller. All of the options must be defined to ensure proper
system functioning.
No.
Options
1
WDT clock source: WDTOSC or T1 (fSYS/4)
2 WDT function: enable or disable
3 CLRWDT instruction(s): one or two clear WDT instruction(s)
4 System oscillator: RC or crystal
5 Pull-high resistors (PA, PB, PC, PD): none or pull-high
6 PWM enable or disable
7 PA0~PA7 wake-up: enable or disable
8 PFD enable or disable
9 Low voltage reset selection: enable or disable LVR function.
Rev. 1.10
20
March 24, 2006
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