Figure 22 frame frequency – Rainbow Electronics HD44780 User Manual

Page 38

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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

µ

s).

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

µ

s

Ч

400

Ч

8 = 11850

µ

s = 11.9 ms

Frame frequency = = 84.3 Hz

1

11.9 ms

1 frame = 3.7

µ

s

Ч

400

Ч

11 = 16300

µ

s = 16.3 ms

Frame frequency = = 61.4 Hz

1

16.3 ms

1 frame = 3.7

µ

s

Ч

200

Ч

16 = 11850

µ

s = 11.9 ms

Frame frequency = = 84.3 Hz

1

11.9 ms

Figure 22 Frame Frequency

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