LC75844M
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9
Example of Serial Data Transfer
When used with 45 segments or more
Serial data must be transferred all 112-bit.
When fewer than 45 segments are used, only 56-bits of serial data need to be sent. However, the display data
D1 to D44 and the control data must be sent.
Note) When fewer than 45 segments are used, transfers such as that shown in the figure below cannot be used.
Control Data Description
(1) P0 to P2 Segment output port/General-purpose output port switching control data
This control data switching output S1/P1 to S4/P4 segment output port and general-purpose output port.
Control data Output pin state
P0 P1 P2 S1/P1 S2/P2 S3/P3 S4/P4
0 0 0 S1 S2 S3 S4
0 0 1 P1 S2 S3 S4
0 1 0 P1 P2 S3 S4
0 1 1 P1 P2 P3 S4
1 0 0 P1 P2 P3 P4
The following shows the correspondence between output pins and display data when the general-purpose output port
is selected.
Output pin Correspondence display data
S1/P1 D1
S2/P2 D5
S3/P3 D9
S4/P4 D13
For example, if output pin S4/P4 is for the general-purpose output port, output pin S4/P4 outputs high and low-level
when display data D13=“1” and D13= “0”, respectively.
(2) DR 1/2 bias drive, 1/3 bias driver switching control data
This control data switching LCD 1/2 bias driver and 1/3 bias driver.
DR Driver method
0 1/3 bias driver
1 1/2 bias driver
Note) Sn (n=1 to 4): Segment output port
Pn (n=1 to 4): General-purpose output port
1 1 0 0 0 0 0 0
56-bit 8-bit
A3 A2 A1 A0 B3 B2 B1 B0
D3 D2 D1 0
D44 D43 D42 D41 D40 D39 D38 D37
1 1 0 0 0 0 0 0
A3 A2 A1 A0 B3 B2 B1 B0
P1 0 BU SC DR P2 P0 0 0 0 0
0
D88 D87 D86 D85 D84 D83 D82 D47 D46 D45 D81
0 1 0 0 0 0 0 0 0 0 0
1 1 0 0 0 0 0 0
56-bit
8-bit
A3 A2 A1 A0 B3 B2 B1 B0
D3 D2 D1 0
D44 D43 D42 D41 D40 D39 D38 D37
P1 0 BU SC DR P2 P0 0 0 0 0
1 1 0 0 0 0 0 0
56-bit 8-bit
A3 A2 A1 A0 B3 B2 B1 B0
0
D88 D87 D86 D85 D84 D83 D82 D81 D47 D46 D45
0 1 0 0 0 0 0 0 0 0 0
