S1C63558 TECHNICAL MANUAL
EPSON
55
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (LCD Driver)
LPWR: LCD power control (ON/OFF) register (FF60H•D0)
Turns the LCD system voltage circuit ON and OFF.
When "1" is written: ON
When "0" is written: OFF
Reading: Valid
When "1" is written to the LPWR register, the LCD system voltage circuit goes ON and generates the LCD
drive voltage. When "0" is written, all the LCD drive voltages go to V
SS
level.
It takes about 100 msec for the LCD drive voltage to stabilize after starting up the LCD system voltage
circuit by writing "1" to the LPWR register.
At initial reset, this register is set to "0".
LDUTY0, LDUTY1: LCD drive duty switching register (FF60H•D2, D3)
Selects the LCD drive duty.
Table 4.7.7.2 Drive duty setting
LDUTY1
1
0
0
LDUTY0
∗
1
0
Drive
duty
1/8
1/16
1/17
Common terminal
used
COM0–COM7
COM0–COM15
COM0–COM16
Maximum segment
number
320 (40
×
8)
640 (40
×
16)
680 (40
×
17)
When 48
×
8 mask option
is selected
384 (48
×
8)
Invalid
Invalid
At initial reset, this register is set to "0". When 48
×
8 is selected by mask option, reset to 1/8 duty.
ALON: LCD all ON control register (FF61H•D1)
Displays the all LCD dots ON.
When "1" is written: All LCD dots displayed
When "0" is written: Normal display
Reading: Valid
By writing "1" to the ALON register, all the LCD dots goes ON, and when "0" is written, it returns to
normal display.
This function outputs an ON waveform to the SEG terminals, and does not affect the content of the
display memory.
ALON has priority over ALOFF.
At initial reset, this register is set to "0".
ALOFF: LCD all OFF control register (FF61H•D2)
Fade outs the all LCD dots.
When "1" is written: All LCD dots fade out
When "0" is written: Normal display
Reading: Valid
By writing "1" to the ALOFF register, all the LCD dots goes OFF, and when "0" is written, it returns to
normal display.
This function outputs an OFF waveform to the SEG terminals, and does not affect the content of the
display memory.
At initial reset, this register is set to "1".