Hitachi AP1 Data Book page 150

L C D - I I I - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Refer to LIQUID CRYSTAL DISPLAY for additional in-
formation.
• OSCILLATOR
A resistor, a ceramic filter circuit or an external oscillator
can be connected to OSC
1
and
O~.
However, a ceramic
filter circuit cannot be used on the HD44795. The oscillator
frequency is initially divided by four to produce the initial
system clock. The different connection methods are shown
in Figure 1.
(1)
External Clock
Oscillator
(2)
Resistor
VIH----h,::::===\...~---_I_I===
1/2
VCC------j~---+..l!r____----+_-­
VIL
:::::;:jtj--i4:::::::::::::::t---
trcp tfcp
tt
SC1
Rf
OS(1
Length of the wirings for OSc. and OS(1
terminals should be minimized because
the oscillation frequency veries depending
on the capacitance of these terminals.
500
400
N
:r
~
300
II
~
200
100
0
300
200
N
:r
~
j
100
o
Rf
"
100
100
HD44190
~
"
~
-
-----
I----
typo
200 300 400
500 600
Rf
(kn)
~
HD44795
~
~'
~
~
~
r------
tYPo (Vee· 5V)
typo (VCC
=
3V)
200 300
Rf(kn)
400
-
500 600
Figure 1 Connection Methods for Oscillator
(to
be continued)
148