ML9040 View Datasheet(PDF) - Oki Electric Industry

Part Name

Description

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ML9040

DOT MATRIX LCD CONTROLLER WITH 16-DOT COMMON DRIVER AND 40-DOT SEGMENT DRIVER

Oki Electric Industry 

¡ Semiconductor

ML9040-Axx/-Bxx

Interface with LCD and MSM5259

Display examples when setting the 5 x 7 dots character font 1-line mode, 5 x 10 dots character font

1-line mode, and 5 x 7 dots character font 2-line mode through instructions are shown in Figures

4, 5, and 6, respectively.

When the 5 x 7 dots character font is set in the 1-line display mode, the COM signals COM9 to

COM16 are output for extinguishing.

Likewise, when the 5 x 10 dots character font (1-line is set), the COM signals COM12 to COM16

are output for display-off.

The display example shows a combination of 16 characters (32 characters for the 2-line display

mode) and the LCD. When the number of MSM5259s are increased according to the increase in

the number of characters, it is possible to display a maximum of 80 characters.

Besides, it is necessary to generate bias voltage required for LCD operation by splitting resistors

outside the IC to input it to ML9040-Axx/-Bxx and MSM5259.

Examples of these bias voltages are shown in Figures 7, 8, 9, and 10. Basically, this can be done

by dividing the voltage by the resistors as shown in Figures 7 and 8. If the value of resistor R is

made larger to reduce system power consumption, the LCD operating margin decreases and the

LCD driving waveform is distorted. To prevent this, a by-pass capacitor is serially connected to

the resistor to lower voltage division impedance caused by the splitting of resistors as shown in

Figures 9 and 10.

As the values of R, VR, and C vary according to the LCD size used and VLCD (LCD drive voltage),

these values have to be determined through actual experimentation in combination with the

LCD.

(Example set values: R = 3.3 to 10kW, VR = 10 to 30kW, and C = 0.0022 mF to 0.047 mF)

Figure 17 shows an application circuit for the ML9040-Axx/-Bxx and MSM5259 including a bias

circuit.

The bias voltage has to maintain the following potential relation:

VDD > V1 > V2 ≥ V3 > V4 > V5

• In the case of 1-line 16 characters display (5 x 7 dots/font)

COM1

LCD

COM8

SEG1

SEG40

ML9040-Axx/-Bxx/-Cxx/-Dxx

DO

CP

DF

L

O1

O40

DI1

MSM5259

CP

LOAD DF DO20 DI21

Figure 4

33

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