LC75890W
www.onsemi.com
25
Display Control and the
INH
Pin
Since the LSI internal data (1/4 duty drive : the display data D1 to D148 and the control data, Static drive : the display
data D1 to D37 and the control data) is undefined when power is first applied, applications should set the INH
pin low
at the same time as power is applied to turn off the display (This sets the S1/P1 to S12/P12, S13 to S36, COM4 to
COM1, and S37/OSCI pins to the V
SS
level.) and during this period send serial data from the controller. The controller
should then set the INH
pin high after the data transfer has completed. This procedure prevents meaningless display at
power on.
(See Figure 4 and Figure 5.)
Notes on the Power On/Off Sequences
Applications should observe the following sequences when turning the LC75890 power on and off.
(See Figures 4 and Figure 5.)
• At power on : Logic block power supply (V
DD
) on LCD driver block power supply (V
LCD
) on
• At power off : LCD driver block power supply (V
LCD
) off Logic block power supply (V
DD
) off
However, if the logic and LCD driver block use a shared power supply, then the power supplies can be turned on and
off at the same time.
(1)1/4 duty drive
Note1 : t10
t20
t30 (t2t3)
tc 10 s min
[Figure 4]
Internal data (D49 to D96)
Internal data (D97 to D148)
BD1 to BD37,BF0 to BF2,
FC0 to FC2,DT,EXF,OC,SC,BU
V
DD
Internal data
Internal data (D1 to D48)
V
LCD
CE
INH
Internal data
W10 to W15,W20 to W25,
W30 to W35,PF0 to PF3,P1A,
P1B to P12A,P12B,P0 to P3
t1
Display data and control
data transferred
t2
Undefined Defined
Undefined
V
IL
1
tc
V
IL
1
t3
Undefined Defined
Undefined
Undefined Defined
Undefined
Undefined Defined Undefined
Undefined Defined Undefined
