LC75844M Datasheet, PDF (11/14 Pages) Sanyo Semicon Device – 1/4 Duty General-Purpose LCD Driver

LC75844M
The INH pin and Display Control
Since the IC internal data (the display data 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 S4/P4, S5
to S22, and COM1 to COM4 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 displays at
power on. (See Figure 3.)
Notes on the Power On/Off Sequences
Applications should observe the following sequence when turning the LC75844M power on and off.
• 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.
Internal data
D1 to D44
P0 to P2
DR, SC, BU
Display and control data transfer
Undefined
Defined
Internal data (D45 to D88)
Undefined
Defined
Undefined
Undefined
Note: t1 ≥ 0
t2 > 0
t3 ≥ 0 (t2 > t3)
tc ^... 10 µs min
Figure 3
Notes on Controller Transfer of Display Data
Since the LC75844M accept display data (D1 to D88) divided into two separate transfer operations, we recommend that
applications transfer all of the display data within a period of less than 30 ms to prevent observable degradation of
display quality.
No. 6235-11/14