Application Circuits

The following table shows the C1, C2 and R1 values corresponding to the different crystal values. (For reference only)

Crystal or Resonator

C1, C2

R1

4MHz Crystal

0pF

10k

W

4MHz Resonator

10pF

12k

W

3.58MHz Crystal

0pF

10k

W

3.58MHz Resonator

25pF

10k

W

2MHz Crystal & Resonator

25pF

10k

W

1MHz Crystal

35pF

27k

W

480kHz Resonator

300pF

9.1k

W

455kHz Resonator

300pF

10k

W

429kHz Resonator

300pF

10k

W

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.

Note:

The resistance and capacitance for reset circuit should be designed in such a way as to ensure that the VDD is

stable and remains within a valid operating voltage range 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.

HT46R46/HT46C46/HT46R47/HT46C47

Rev. 1.00

22

December 28, 2004

O S C 1

O S C 2

O S C

C i r c u i t

R E S

0 . 1 m F *

1 0 0 k W

V D D

V S S

0 . 1 m F

0 . 0 1 m F *

1 0 k W

R C S y s t e m O s c i l l a t o r

O S C 1

O S C 2

4 7 0 p F

O S C 1

O S C 2

R 1

C 1

C 2

C r y s t a l S y s t e m O s c i l l a t o r

F o r t h e v a l u e s ,

s e e t a b l e b e l o w

O S C C i r c u i t

S e e R i g h t S i d e

H T 4 6 R 4 6 / H T 4 6 C 4 6

H T 4 6 R 4 7 / H T 4 6 C 4 7

P D 0 / P W M

P B 0 / A N 0

P B 3 / A N 3

P A 0 ~ P A 2

P A 3 / P F D

P A 4 / T M R

P A 5 / I N T

P A 6 ~ P A 7