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CHAPTER 12 APPLICATIONS OF LCD CONTROLLER/DRIVER
The LCD controller/driver of the
μ
PD78064, 78064Y, 780308, and 780308Y subseries is described next.
(a) Function of LCD controller/driver
The LCD controller/driver has the following functions:
<1> Automatically outputs segment and common signals by automatically reading the display data memory.
<2> Five types of display modes are available:
Static mode
1/2 duty mode (1/2 bias)
1/3 duty mode (1/2 bias)
1/3 duty mode (1/3 bias)
1/4 duty mode (1/3 bias)
<3> Four types of frame frequencies can be selected in each display mode.
<4> Up to 40 segment signal outputs (S0 through S39) and four common signal outputs (COM0 through
COM3) are available. Sixteen segment outputs can be set in the input/output port mode in 2-bit units
(P80/S39 through P87/S32, and P90/S31 through P97/S24).
<5> Divider resistors for generating the LCD drive voltage can be provided to the mask ROM model by mask
option.
<6>
Can operate on the subsystem clock.
Table 12-1 shows the maximum number of pixels that can be displayed in each display mode.
Table 12-1. Maximum Number of Pixels for Display
Bias
Time Division
Common Signal Used
Maximum Number of Pixels
–
Static
COM0 (COM0-COM3)
40 (40 segments
×
1 common)
Note 1
1/2
2
COM0, COM1
80 (40 segments
×
2 common)
Note 2
3
COM0-COM2
120 (40 segments
×
3 common)
Note 3
1/3
3
COM0-COM2
4
COM0-COM3
160 (40 segments
×
4 common)
Note 4
Notes 1.
Can display 5 digits with eight segments for each digit on an 8-segment LCD panel.
2.
Can display 10 digits with four segments for each digit on an 8-segment LCD panel.
3.
Can display 13 digits with three segments for each digit on an 8-segment LCD panel.
4.
Can display 20 digits with two segments for each digit on an 8-segment LCD panel.