HD404818 Datasheet, PDF (39/100 Pages) Hitachi Semiconductor – 16-digit LCD driver

HD404818 Series
Internal Oscillator Circuit
Figure 20 shows the block diagram of the internal oscillator circuit. A ceramic oscillator can be connected
to OSC ₁ and OSC₂. A 32.768-kHz crystal oscillator can be connected to X1 and X2. External clock
operation is available for the system oscillator.
OSC₁
OSC₂
X1
X2
System ^{f OSC}
oscillator
1/4
divider
circuit
Subsystem ^f X
oscillator
1/8
divider
circuit
Timing
f _cyc
generator
Mode
circuit
control
circuit
Timing
generator
circuit
f _SUB
Figure 20 Internal Oscillator Circuit
System clock
(ø_CPU)
System clock
(ø_PER)
Timer-base
clock (ø_CLK)
,_D0
RESET
OSC₂
OSC₁
V_CC
$&',-!"'.0$*+ ^NUMG
GND
COMP₁/D₁₃
TEST
X1
X2
GND
SCK/R0₀
Figure 21 Layout of Crystal and Ceramic Oscillators
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