HD66421 Datasheet, PDF (31/46 Pages) Hitachi Semiconductor – (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)

Preliminary
Rev. 1.1E '99.02.10
HD66421
Power On/Off Procedure
Figure 29 shows the procedure for turning the
power supply on and off. This procedure must be
strictly followed to prevent incorrect display
because the HD66421 incorporates a power
supply circuit.
Turn on power (power-on reset)
Set PWR,AMP bit to 1 (control register 1)
Boosting starts
Set CNF, ADC, DTY1, DTY0, INC bits according to
the operating mode (control register1 and 2)
Power on
Write data to registers and RAM as required
Set DISP bit to 1 (control register 1)
Clear DISP bit to 0 (control register 1)
Clear PWR,AMP bit to 0 (control register 1)
Boosting halts ^{Power off}
Turn off power
Figure 29 Procedure for Turning Power Supply On/Off
31