Hitachi AP1 Data Book page 57

-------------------------------------------------------HMCS44C,HMCS44CL
• OSCILLATOR
The HMCS44C contains its own oscillator and frequency di-
vider (CPO). The user can obtain the desired timing for opera-
tion of the LSI by merely connecting an resistor Rf or ceramic
filter circuit (Internal Clock Operation).
The OSC
I
clock frequency is internally divided by four to pro-
duce the internal system clocks.
The user may exchange the external parts for the same LSI to
select either of these two operational modes as shown in Figure
24. There is no need of specifying it by using the mask option.
(a) Internal Clock Operation Using Resistor Rt
Wiring of OSC. and OSCz terminals should be as short as
possible because the oscillation frequency is
modified by capacitance of these terminals.
(b) Internal Clock Operation Using Ceramic Filter Circuit (Built-in CPG ; Ceramic Filter Oscillator)
(This is not applied to HMCS44Cl.)
Ceramic p C '
Filter
C2
GND
OSC.
Ceramic Filter: CSB400P (MURATA)
At :
lMO:!:10%
C. : 2200pF± 10% (ceramic capacitor)
C2 : 4 70pF:!: 10% (ceramic capacitor)
F
C
• _ -....... --10SC.
~~~~mic ~
C2
--+--IOSCz
'-----
Ceramic Filter: FCR-400K (TDK)
R, : lMO±10%
C. l000pF:!: 10% (ceramic capacitor)
C2 : l000pF:!: 10% (ceramic capacitor)
The. ceramic filter oscillation does not apply when using "Halt" and
not resetting at the time of "Halt" cancellation.
This circuit is the example of the typical use. As the oscillation
characteristics is not guaranteed. please consider and examine the
circuit constants carefully on your application.
Figure 24 Clock Operation Mode
55
DUty=-TT'T xl00%
h+ I