HT48R70A-1 Holtek Semiconductor Inc, HT48R70A-1 Datasheet - Page 20

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

Application Circuits
Note:
Rev. 1.60
The resistance and capacitance for reset circuit should be designed to ensure that the VDD is stable and re-
mains in a valid range of the operating voltage before bringing RES to high.
²*² Make the length of the wiring, which is connected to the RES pin as short as possible, to avoid noise
interference.
The following table shows the C1, C2 and R1 value according different crystal values. (For reference only)
4MHz Crystal
4MHz Resonator
3.58MHz Crystal
3.58MHz Resonator
2MHz Crystal & Resonator
1MHz Crystal
480kHz Resonator
455kHz Resonator
429kHz Resonator
The function of the resistor R1 is to ensure that the oscillator will switch off should low voltage condi-
tions occur. Such a low voltage, as mentioned here, is one which is less than the lowest value of the
MCU operating voltage. Note however that if the LVR is enabled then R1 can be removed.
m
W
W
m
m
Crystal or Resonator
20
C1, C2
300pF
300pF
300pF
10pF
25pF
25pF
35pF
0pF
0pF
HT48R70A-1/HT48C70-1
W
W
9.1kW
10kW
12kW
10kW
10kW
10kW
27kW
10kW
10kW
R1
June 9, 2004