Hitachi AP1 Data Book page 79

~------------------------------------------------------HMCS45C,HMCS45CL
Both input and output are at high impedance
state. Since an input circuit is OFF, any current
other than the Stand-by Supply Current (or Halt
Current) does not flow even if an input signal
changes.
45C gets into operation from the status just before the Halt State.
The halt timing is shown in Figure 23.
CAUTION
If, during the Halt State, the external reset input is applied
(RESET = "1" ("High" leve!), the internal status is not held. When the
Hr:T
pin is set to "1" ("High" level), the HMCS-
Vcc ________________
~
HIT
~------------------tHLT--------------~
..
Figure 23 Halt Timing
• OSCILLATOR
The HMCS45C 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 Rf
Wiring of OSC, and OSC2 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 HMCS45Cl.)
~ C'
__ --.--IOSC,
~i~::rmic
c::I
C2
-+----,
OSC2
GND
~------
Ceramic Filter: CSB400P (MURATA)
R, : 1MO:!:10%
C, : 2200pF:!: 10% (ceramic capacitor)
C2 : 47OpF:!: 10% (ceramic capacitor)
F
C
' _-_-IOSC,
~~:e~miC
c::I
Rf
C2
..... - -....... -IOSC2
L.--_ _
Ceramic Filter: FCR-400K (TDK)
RI : 1MO:!:10%
C, 1 000 pF
!:
10% (ceramic capacitor)
C2 : 1000pF! 10% (ceramic capacitor)
The ceramic filter oscillation does not apply when using "Half' 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.
(c) Exte,.o' C'ock Ope'O.O" (E.te,.o'
CP~
T., T' J -=
~n
: : :
2=~
3:;
V
Duty= _T_I_
x
100%
Th+TI
Figure 24 Clock Operation Mode
77