User Manual

HD44780U
38
Relationship between Oscillation Frequency and Liquid Crystal Display Frame
Frequency
The liquid crystal display frame frequencies of Figure 22 apply only when the oscillation frequency is 270
kHz (one clock pulse of 3.7 µs).
1
2
3
4
8
1
2
1
2
3
4
11
1
2
1
2
3
4
16
1
2
400 clocks
400 clocks
200 clocks
1 frame
1 frame
1 frame
1/8 duty cycle
1/11 duty cycle
1/16 duty cycle
V
CC
V1
V2 (V3)
V4
V5
V
CC
V1
V2 (V3)
V4
V5
V
CC
V1
V2
V3
V4
V5
COM1
COM1
COM1
1 frame = 3.7 µs × 400 × 8 = 11850 µs = 11.9 ms
Frame frequency = = 84.3 Hz
1
11.9 ms
1 frame = 3.7 µs × 400 × 11 = 16300 µs = 16.3 ms
Frame frequency = = 61.4 Hz
1
16.3 ms
1 frame = 3.7 µs × 200 × 16 = 11850 µs = 11.9 ms
Frame frequency = = 84.3 Hz
1
11.9 ms
Figure 22 Frame Frequency