HD44780U Datasheet, PDF (38/59 Pages) Hitachi Semiconductor – Dot Matrix Liquid Crystal Display Controller/Driver

HD44780U
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).
1/8 duty cycle
COM1
1
V_CC
V1
V2 (V3)
V4
V5
400 clocks
2
3
4
1 frame
1 frame = 3.7 µs × 400 × 8 = 11850 µs = 11.9 ms
Frame frequency = ¹ = 84.3 Hz
11.9 ms
8
1
2
1/11 duty cycle
COM1
1
V_CC
V1
V2 (V3)
V4
V5
400 clocks
2
3
4
1 frame
1 frame = 3.7 µs × 400 × 11 = 16300 µs = 16.3 ms
Frame frequency =
1
= 61.4 Hz
16.3 ms
1/16 duty cycle
200 clocks
COM1
V_CC
V1
V2
V3
V4
V5
1
2
3
4
1 frame
11
1
2
16
1
2
1 frame = 3.7 µs × 200 × 16 = 11850 µs = 11.9 ms
Frame frequency = ¹ = 84.3 Hz
11.9 ms
Figure 22 Frame Frequency
38