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 VSS 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

LDUTY0

Drive

Common terminal

Maximum segment

When 48 8 mask option

duty

used

number

is selected

 

 

1

1/8

COM0–COM7

320 (40

8)

384 (48 8)

0

1

1/16

COM0–COM15

640 (40

16)

Invalid

0

0

1/17

COM0–COM16

680 (40

17)

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".

S1C63558 TECHNICAL MANUAL

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