Datasheet

RL78/L12 CHAPTER 14 LCD CONTROLLER/DRIVER

R01UH0330EJ0200 Rev.2.00 627

Dec 13, 2013

To use the LCD display data register when the number of time slices is static, two, three, or four, the lower four bits and

higher four bits of each address of the LCD display data register become an A-pattern area and a B-pattern area,

respectively.

The correspondences between A-pattern area data and COM signals are as follows: bit 0 ⇔ COM0, bit 1 ⇔ COM1, bit

2 ⇔ COM2, and bit 3 ⇔ COM3.

The correspondences between B-pattern area data and COM signals are as follows: bit 4 ⇔ COM0, bit 5 ⇔ COM1, bit

6 ⇔ COM2, and bit 7 ⇔ COM3.

A-pattern area data will be displayed on the LCD panel when BLON = LCDSEL = 0 has been selected, and B-pattern

area data will be displayed on the LCD panel when BLON = 0 and LCDSEL = 1 have been selected.

14.5 Selection of LCD Display Register

With RL78/L12, to use the LCD display data registers when the number of time slices is static, two, three, or four, the

LCD display data register can be selected from the following three types, according to the BLON and LCDSEL bit settings.

• Displaying an A-pattern area data (lower four bits of LCD display data register)

• Displaying a B-pattern area data (higher four bits of LCD display data register)

• Alternately displaying A-pattern and B-pattern area data (blinking display corresponding to the constant-period

interrupt timing of the real-time clock (RTC))

Caution If the normal liquid crystal waveform is displayed when the number of time slices is eight, LCD

display data registers (A-pattern, B-pattern, or blinking display) cannot be selected.

Figure 14-15. Example of Setting LCD Display Registers When Pattern Is Changed

Name

Address Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

COM

… … …

SEG5 F0405H

SEG4 F0404H

SEG3 F0403H

SEG2 F0402H

SEG1 F0401H

SEG0 F0400H

B-pattern area A-pattern area

Set these bits to 1 for blinking display

Set a complement to these bits for blinking display

A-pattern area and B-pattern area are alternately

displayed when blinking display (BLON = 1) is selected