HT46R321 datasheet(24/45 Pages) HOLTEK

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Application Circuits

Note:

1. Crystal/resonator system oscillators

For crystal oscillators, C1 and C2 are only required for some crystal frequencies to ensure oscillation. For

resonator applications C1 and C2 are normally required for oscillation to occur. For most applications it is

not necessary to add R1. However if the LVR function is disabled, and if it is required to stop the oscillator

when VDD falls below its operating range, it is recommended that R1 is added. The values of C1 and C2

should be selected in consultation with the crystal/resonator manufacturer specifications.

2. Reset circuit

The reset circuit resistance and capacitance values should be chosen to ensure that VDD is stable and re-

mains within its operating voltage range before the RES pin reaches a high level. Ensure that the length of

the wiring connected to the RES pin is kept as short as possible, to avoid noise interference.

3. For applications where noise may interfere with the reset circuit and for details on the oscillator external

components, refer to Application Note HA0075E for more information.

HT46R321

Rev. 1.00

August 3, 2007

O S C 1

O S C 2

O S C

C i r c u i t

O S C C i r c u i t

H T 4 6 R 3 2 1

P D 0 / P W M 0

P D 1 / P W M 1

P D 2 / P C K

P D 3 , P D 4

P D 5 / T M R

P D 6 / I N T

P B 0 / A N 0 ~

P B 5 / A N 5

P A 0 ~ P A 2

P A 3 / P F D

P A 4 ~ P A 7

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

2 4 k W < R O S C < 1 M W

V D D

R O S C

f S Y S / 4

O S C 1

O S C 2

4 7 0 p F

A P N

A P P

P B 0 / A N 0 A P O

C r y s t a l / R e s o n a t o r

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

F o r R 1 , C 1 , C 2 s e e n o t e

C 1

O S C 1

O S C 2

R 1

C 2

R E S

0 . 1 m F

1 0 0 k W

V D D

V S S

0 . 1 m F

V D D

R e s e t

C i r c u i t

HT46R321 Datasheet(PDF) 24 Page - Holtek Semiconductor Inc

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