PEDL9040A-03
¡ Semiconductor
ML9040A-Axx/-Bxx
Interface with LCD and MSM5259
Displayexampleswhensettingthe5x7dotscharacterfont1-linemode, 5x10dotscharacterfont
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 COM to
9
COM are output for extinguishing.
16
Likewise, when the 5 x 10 dots character font (1-line is set), the COM signals COM to COM
12
16
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 ML9040A-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 valuesof R, VR, and CvaryaccordingtotheLCDsizeused andV
(LCDdrivevoltage),
LCD
these values have to be determined through actual experimentation in combination with the
LCD.
(Example set values: R = 3.3 to 10kW, V = 10 to 30kW, and C = 0.0022 mF to 0.047 mF)
R
Figure 17 shows an application circuit for the ML9040A-Axx/-Bxx and MSM5259 including a
bias circuit.
The bias voltage has to maintain the following potential relation:
V
DD
> V > V ≥ V > V > V
1 2 3 4 5
• In the case of 1-line 16 characters display (5 x 7 dots/font)
COM
COM
1
LCD
8
SEG
SEG
O
1
O
1
40
1
40
DO
CP
DI
MSM5259
DF DO
ML9040A-Axx/-Bxx
CP
DF
L
LOAD
DI
20
21
Figure 4
33/49
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