hd66712u Renesas Electronics Corporation., hd66712u Datasheet - Page 72

Manufacturer Part Number

hd66712u

Description

Dot-matrix Liquid Crystal Display Controller/driver - Hitachi Semiconductor

Manufacturer

Renesas Electronics Corporation.

Datasheet

1.HD66712U.pdf (88 pages)

Low Power Mode

When the extension driver is not used (EXT = Low) with extension register enabled (RE = 1), the

HD66712 enters low power mode by setting the low-power mode bit (LP) to 1. During low-power mode,

as the internal operation clock is divided by 2 (2-line/4-line display mode) or by 4 (1-line display mode),

the execution time of each instruction becomes two times or four times longer than normal. In addition,

as the frame frequency decreases to 5/6, display quality might be affected.

In addition, since the display is not shifted in low power mode, display shift must be cleared with the

return home instruction before setting low power mode. The amount of horizontal scroll must also be

cleared (HDS = 000000). Moreover, because the display enters a shift state after clearing low-power

mode, the home return instruction must be used to clear display shift at that time.

Clear horizontal scroll quantity

Extended register enable

Set a low power mode

Clear low power mode

Low power operation

HDS = 000000

Return home

Figure 33 Usage of Low Power Mode

Note: The execution time of an instruction in low-power

Note: Up until this instruction, execution time is two

Note: Because the display enters a shift state, be sure

RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

RS R/W

RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

R/W

mode becomes two times or four times longer

then normal. The frame frequency also

decreases by 5/6.

times or four times longer than normal.

to execute this instruction.

DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0

HD66712U

435