HD404849 Datasheet, PDF (100/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404849 Series
LCD Control Register (LCR: $01B): Four-bit write-only register which controls LCD blanking, on/off
switching of the liquid-crystal display’s power supply division resistor, display in watch and subactive
modes, and connection of the LCD division resistor, as shown in figure 86.
• Blank/display
Blank: Segment signals are turned off, regardless of LCD RAM data setting.
Display: LCD RAM data is output as segment signals.
• Power switch on/off
Off: The power switch is off.
On: The power switch is on and V₁ is V_CC.
• Watch/subactive mode display
Off: In watch and subactive modes, all common and segment pins are grounded and the liquid-crystal
power switch is turned off.
On: In watch and subactive modes, LCD RAM data is output as segment signals.
• LCD power supply division resistor switch
Off: Division resistor is disconnected.
On: Division resistor is connected.
LCD display control register (LCR: $01B)
Bit
Initial value
Read/Write
Bit name
3
0
W
LCR3
2
0
W
LCR2
1
0
W
LCR1
0
0
W
LCR0
LCR3
LCD power supply division
resistor switch
0
On
1
Off
LCR2
Display on/off selection in
watch and subactive modes
0
Off
1
On
LCR1
0
1
Power switch on/off
Off
On
LCR0
0
1
Blank/display
Blank
Display
Figure 86 LCD Control Register (LCR)
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