H49R50A-1 Datasheet, PDF (24/45 Pages) Holtek Semiconductor Inc – LCD Type 8-Bit MCU

HT49R50A-1/HT49C50-1/HT49C50L
Application Circuits
For HT49R50A-1/HT49C50-1 Application Circuit
V DD
0 .0 1 m F *
VDD
100kW
0 .1 m F
RES
10kW
0 .1 m F *
VSS
O SC
C ir c u it
S e e r ig h t s id e
O SC1
O SC2
C O M 0~C O M 3
S E G 0~S E G 31
V LC D
C1
C2
V1
V2
32768H z
O SC3
10pF
O SC4
P A 0~P A 7
P B 0~P B 7
P C 0~P C 3
IN T 0
IN T 1
TM R 0
TM R 1
H T 4 9 R 5 0 A -1 /H T 4 9 C 5 0 -1
LC D
PANEL
L C D P o w e r S u p p ly
0 .1 m F
0 .1 m F
0 .1 m F
V DD
470pF
R O SC
fS Y S /4
O SC1
O SC2
C1
O SC1
C2
R1
O SC2
R C S y s te m O s c illa to r
30kW < R OSC< 750kW
C r y s ta l S y s te m O s c illa to r
F o r th e v a lu e s ,
s e e ta b le b e lo w
O SC1
O SC2
3 2 7 6 8 H z C ry s ta l S y s te m
O s c illa to r
O S C 1 a n d O S C 2 le ft
u n c o n n e c te d
O S C C ir c u it
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
10kW
4MHz Resonator
10pF
12kW
3.58MHz Crystal
0pF
10kW
3.58MHz Resonator
25pF
10kW
2MHz Crystal & Resonator
25pF
10kW
1MHz Crystal
35pF
27kW
480kHz Resonator
300pF
9.1kW
455kHz Resonator
300pF
10kW
429kHz Resonator
300pF
10kW
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.
Rev. 2.00
24
November 29, 2005