Datasheet

Table Of Contents
Section 21 LCD Controller/Driver
Rev. 2.00 Jul. 04, 2007 Page 460 of 692
REJ09B0309-0200
21.3.2 LCD Control Register (LCR)
LCR controls LCD drive power supply and display data, and selects the frame frequency.
Bit Bit Name
Initial
Value
R/W Description
7 — 1 Reserved
This bit is always read as 1 and cannot be modified.
6 PSW 0 R/W LCD Drive Power Supply Control
Can be used to turn off the LCD drive power supply when
LCD display is not required in power-down mode, or when
an external power supply is used. When the ACT bit is
cleared to 0 or in standby mode, the LCD drive power
supply is turned off regardless of the setting of this bit.
0: LCD drive power supply is turned off
1: LCD drive power supply is turned on
5 ACT 0 R/W Display Function Activate
Specifies whether or not the LCD controller/driver is used.
Clearing this bit to 0 halts operation of the LCD
controller/driver. The LCD drive power supply is also
turned off, regardless of the setting of the PSW bit.
However, register contents are retained.
0: LCD controller/driver halts
1: LCD controller/driver operates
4 DISP 0 R/W Display Data Control
Specifies whether the LCD RAM contents are displayed or
blank data is displayed regardless of the LCD RAM
contents.
0: Blank data is displayed
1: LCD RAM data is displayed
3
2
1
0
CKS3
CKS2
CKS1
CKS0
0
0
0
0
R/W
R/W
R/W
R/W
Frame Frequency Select 3 to 0
Select the operating clock and the frame frequency.
However, in subactive mode, watch mode, and subsleep
mode, the system clock (φ) is halted. Therefore display
operations are not performed if one of the clocks from φ/2
to φ/256 is selected. If LCD display is required in these
modes, φ
W
, φ
W
/2, or φ
W
/4 must be selected as the operating
clock.
For details, see table 21.4.