Lcd Control Register (Lcr) - Hitachi HD6473867 Hardware Manual

13.2.2

LCD Control Register (LCR)

Bit
—
Initial value
Read/Write —
LCR is an 8-bit read/write register which performs LCD drive power supply on/off control and
display data control, and selects the frame frequency.
LCR is initialized to H'80 upon reset.
Bit 7: Reserved bit
Bit 7 is reserved; it is always read as 1 and cannot be modified.
Bit 6: LCD drive power supply on/off control (PSW)
Bit 6 can be used to turn the LCD drive power supply off when LCD display is not required in a
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.
Bit 6
PSW Description
0 LCD drive power supply off
1 LCD drive power supply on
Bit 5: Display function activate (ACT)
Bit 5 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.
Bit 5
ACT Description
0 LCD controller/driver operation halted
1 LCD controller/driver operates
7 6
PSW ACT
1 0
R/W R/W
5 4 3
DISP CKS3
0 0 0
R/W R/W
(initial value)
331
2 1
CKS2 CKS1 CKS0
0 0
R/W R/W
(initial value)
0
0
R/W