LC75879PT_13 Datasheet, PDF (33/35 Pages) ON Semiconductor – LCD Display Driver

LC75879PT
Notes on Controller Transfer of Display Data
When using the LC75879PT in 1/4 duty, applications transfer the display data (D1 to D272) in four operations,
and in 1/3 duty, they transfer the display data (D1 to D207) in three operations. In either case, applications
should transfer all of the display data within 30 ms to maintain the quality of displayed image.
S69/OSCI Pin Peripheral Circuit
(1) Internal oscillator operating mode (control data OC=0)
Connect the S69/OSCI pin to the LCD panel when the internal oscillator operating mode is selected.
OSCI/S69
To LCD panel
(2) External clock operating mode (control data OC=1)
When the external clock operating mode is selected, insert a current protection resistor Rg (2.2 to 22kΩ) between
the S69/OSCI pin and external clock output pin (external oscillator). Determine the value of the resistance according
to the allowable current value at the external clock output pin. Also make sure that the waveform of the external
clock is not heavily distorted.
External clock output pin
External oscillator
OSCI/S69
Rg
Note: Allowable current value at external clock output pin >
VDD
Rg
(3) Unused pin treatment
When the S69/OSCI pin is not to be used, select the internal oscillator operating mode (setting control data OC to 0)
to keep the pin open.
OSCI/S69
OPEN
P1 to P4 pin peripheral circuit
It is recommended the circuit shown below be used to adjust the brightness of the LED backlight using the PWM output
P1 to P4
+5V
LED
P1 to P4
No.A1687-33/35