HT48R03 Holtek Semiconductor, HT48R03 Datasheet - Page 21

• Manufacturer Part Number: HT48R03
• Description: (HT48R01 - HT48R03) 10-Pin MSOP I/O Type 8-Bit OTP MCU
• Manufacturer: Holtek Semiconductor

Application Circuits
Note: The resistance and capacitance for the reset circuit should be designed to ensure that VDD is stable and
Rev. 1.00
remains in a valid range of the operating voltage before bringing RES high.
interference.
The following table shows the C1, C2 and R1 values corresponding to the different crystal values. (For refer-
ence only)
W
m
* Make the length of the wiring, which is connected to the RES pin as short as possible, to avoid noise
8MHz Crystal & Resonator
4MHz Crystal
4MHz Resonator
3.58MHz Crystal
3.58MHz Resonator
2MHz Crystal & Resonator
1MHz Crystal
480kHz Resonator
455kHz Resonator
429kHz Resonator
400kHz 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.
W
m
m
Crystal or Resonator
21
C1, C2
300pF
300pF
300pF
300pF
HT48R01/HT48R02/HT48R03
35pF
10pF
10pF
10pF
10pF
35pF
68pF
W
December 20, 2006
3.9k
10k
12k
12k
12k
12k
18k
10k
10k
10k
10k
R1
W