![](http://datasheet.mmic.net.cn/220000/LC74725_datasheet_15479700/LC74725_11.png)
No. 5213-11/16
LC74725, 74725M
Second byte
|
COMMAND4 (Display control setup command)
First byte
Second byte
Register content
DA0 to DA7
Register name
State
Function
Note
7
—
0
Second byte identification bit
6
LC
0
An LC oscillator is used for the dot clock.
Selects the dot clock used in horizontal
character display.
1
A crystal oscillator is used for the dot clock.
5
HP5
(MSB)
0
1
4
HP4
0
1
3
HP3
0
1
2
HP2
0
1
1
HP1
0
1
0
HP0
(LSB)
0
1
The horizontal display start position is
set by the 6 bits HP0 to HP5.
The weight of bit 1 is 2Tc.
If HS is the horizontal start position then:
5
HS = Tc
×
(2
2
n
HP
n
)
n = 0
Tc: Period of the oscillator connected to OSCIN/OSCOUT in
operating mode.
Register content
DA0 to DA7
Register name
State
Function
Note
7
—
1
6
—
1
Command 4 identification code
Display control setup
5
—
0
4
—
0
3
TSTMOD
0
Normal operating mode
This bit must be zero.
1
Test mode
2
RAMERS
0
The RAM erase operation requires about
500 μs (It is executed in the DSPOFF state.)
1
Erase display RAM (set to 3F hexadecimal)
1
OSCSTP
0
Do not stop the crystal oscillator and LC oscillator circuits.
Valid when character display is off in
external synchronization mode.
1
Stop the crystal oscillator and LC oscillator circuits.
0
SYSRST
0
Reset occurs when the CS1 pin is low, and
the reset is cleared when CS1 goes high.
1
Reset all registers and turn the display off.
Register content
DA0 to DA7
Register name
State
Function
Note
7
—
0
Second byte identification bit
6
EGL
0
Border level 0 (V
BK0
)
Border level 1 (V
BK1
)
Interlaced (262.5H per field)
Switches the border level
1
5
NON
0
Switches between interlaced and
noninterlaced
1
Noninterlaced (263H per field)
4
EG
0
Border off
1
Border on
3
BK1
0
Blinking period: about 0.5 s
Switches the blinking period.
1
Blinking period: about 1.0 s
0
Blinking off
When blinking is specified for reversed
characters, the blinking will be between
normal character and reversed character
display.
2
BK0
1
Blinking on
1
RV
0
Reverse (character reversing) off
1
Reverse (character reversing) on
0
DSPON
0
Character display off
1
Character display on