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14. Dot Matrix LCD Controller (H8/3854 Group)
14.3.8
Power-On and Power-Off Procedures
As the LCD controller incorporates a complete power supply circuit, the procedures shown in
figure 14.10 must be followed when powering on and off. Failure to follow these procedures may
result in an abnormal display.
Note: * Do not set to 1 when an external power supply is used.
14.3.9
Power Supply Circuit
The LCD controller has a built-in bleeder resistance circuit for LCD drive. In standby mode, the
voltage circuits are automatically turned off and the power consumption of the power supply
circuit falls to zero. The power supply circuit can be turned on and off by a command, and an
external power supply circuit should be used if the current capacity of the built-in step-up circuit is
insufficient.
LCD Drive Level
Six power supply levels⎯V1, V2, V3, V3, V4, V5, and V
V1 to V
power supplies are normally generated by means of resistive division.
SS
When 1/4 bias is used for LCD display, the V3OUT and V4OUT pins should be shorted; when 1/5
bias is used, the V3OUT and V4OUT pins should be left open.
Rev.3.00 Jul. 19, 2007 page 396 of 532
REJ09B0397-0300
Starting
display
Set DDTY1 according to mode used
Set LPS1*, LPS0*, and DISP to 1
Halting
display
Clear LPS1, LPS0, and DISP to 0
Figure 14.10 Power-On and Power-Off Procedures
Write data
⎯are necessary for LCD drive. The
SS
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