HD44780U Hitachi Semiconductor (acquired by Renesas), HD44780U Datasheet - Page 39

• Manufacturer Part Number: HD44780U
• Description: Dot Matrix Liquid Crystal Display Controller/driver
• Manufacturer: Hitachi Semiconductor (acquired by Renesas)

Relationship between Oscillation Frequency and Liquid Crystal Display Frame
Frequency
The liquid crystal display frame frequencies of Figure 24 apply only when the oscillation frequency is
270 kHz (one clock pulse of 3.7 µs).
1/8 duty cycle
COM1
1/11 duty cycle
COM1
1/16 duty cycle
COM1
V
V1
V2 (V3)
V4
V5
1 frame = 3.7 s
Frame frequency =
V
V1
V2 (V3)
V4
V5
1 frame = 3.7 s
Frame frequency =
V
V1
V2
V3
V4
V5
1 frame = 3.7 s
Frame frequency =
CC
CC
CC
1
1
1
400
400
200
11.9 ms
11.9 ms
16.3 ms
1
1
1
8 = 11850 s = 11.9 ms
11 = 16300 s = 16.3 ms
16 = 11850 s = 11.9 ms
Figure 24 Frame Frequency
2
2
2
400 clocks
400 clocks
200 clocks
= 84.3 Hz
= 84.3 Hz
= 61.4 Hz
3
3
3
1 frame
1 frame
1 frame
4
4
4
16
11
8
1
1
1
2
2
2
HD44780U
205