PEDL9040A-03
¡ Semiconductor
ML9040A-Axx/-Bxx
Cursor/Blink Control Circuit
This is a circuit that generates the LCD cursor and blink.
This circuit is under the control of the CPU program.
The display of the cursor and blink on the LCD is made at a position corresponding to the
DD RAM address that is set in the ADC.
The figure below shows an example of the cursor/blink position when the value of ADC
is set to "07" (hex.).
DB6
L
DB0
H
ADC
L
0
L
L
H
H
7
First
digit
2
3
4
5
6
7
8
9
79 80
4E 4F
In 1-line display mode
00 01 02 05 04 05 06 07 08
Cursor and blink position
First
digit
2
3
4
5
6
7
8
9
39 40
26 27
First line
00 01 02 03 04 05 06 07 08
40 41 42 43 44 45 46 47 48
In 2-line display mode
Second line
66 67
Cursor and blink position
(Note) The cursor and blink are displayed even when the CG RAM address is set in the
ADC. For this reason, it is necessary to inhibit the cursor and blink display while
the CG RAM address is set in the ADC.
LCD Display Circuit (COM to COM , SEG to SEG , L, CP, DO, and DF)
1
16
1
40
As the ML9040A-Axx/-Bxx provides the COM signal outputs (16 outputs) and the SEG
signal outputs (40 outputs), it can display 8 characters (1-line display) or 16 characters (2-
line display) as a unit.
SEG to SEG are used to display 8-digit display on the LCD. To expand the display, an
1
40
MSM5259 is used.
The MSM5259, 40-dot segment driver, is used for expansion of the SEG signal output.
Interface with the MSM5259 is made through data output pin (DO), clock output pin (CP),
latch output pin (L), and display frequency pin (DF). The character pattern data is serially
transferred to MSM5259 through DO and CP. When the data of 72 characters 360-bit (= 5-
bit/ch. x 72 ch. = 1-line display) or 32 characters 160-bit (5-bit/ch. x 32 ch. = 2-line display)
is output, the latch pulse is also output through pin L. By this latch pulse, the data
transferred serially to MSM5259 is latched to be used as display data. The display
frequency signal (DF) required when LCD is displayed is also output from DF pin
synchronously with this latch pulse.
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