HD66750 Datasheet, PDF (49/96 Pages) Hitachi Semiconductor – 128 x 128-dot Graphics LCD Controller/Driver with Four-grayscale Functions

HD66750/1
Oscillation Circuit
The HD66750/1 can either be supplied with operating pulses externally (external clock mode) or oscillate
using an internal R-C oscillator with an external oscillator-resistor (external resistor oscillation mode).
Note that in R-C oscillation, the oscillation frequency is changed according to the internal capacitance
value, the external resistance value, or operating power-supply voltage.
1) External clock mode
Cloc k
(70 kHz)
OSC1
HD66750/1
Dumping resistance
(1.5 kΩ)
2) External resistor oscillation mode
The oscillator frequency can be
OSC 1
adjusted by oscillator resistor
Rf
OSC 2
(Rf). If Rf is increased or power
supply voltage is decreased, the
HD66750/1
oscillation frequency decreases.
For the relationship between Rf
resistor value and oscillation
frequency, see the Electric
Characteristics Notes section.
Figure 32 Oscillation Circuits
Table 18 Relationship between Liquid Crystal Drive Duty Ratio and Frame Frequency
LCD Duty
Recommended Frame
NL3Ð0 Set Value Drive Bias Value Frequency
One-frame Clock
1/16
0001
1/6
70 Hz
1024
1/24
0010
1/6
70 Hz
1032
1/32
0011
1/6
70 Hz
1024
1/40
0100
1/7
69 Hz
1040
1/48
0101
1/8
71 Hz
1008
1/56
0110
1/8
71 Hz
1008
1/64
0111
1/9
70 Hz
1024
1/72
1000
1/9.5
71 Hz
1008
1/80
1001
1/10
69 Hz
1040
1/88
1010
1/10
68 Hz
1056
1/96
1011
1/10
68 Hz
1056
1/104
1100
1/11
69 Hz
1040
1/112
1101
1/11
71 Hz
1008
1/120
1110
1/11
67 Hz
1080
1/128
1111
1/11
70 Hz
1024
Note: The frame frequency above is for 72-kHz operation and proportions the oscillation frequency (fosc).
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