No. 5213-11/16
LC74725, 74725M
Second byte
⑤ 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
6LC
0
An LC oscillator is used for the dot clock.
Selects the dot clock used in horizontal
1A crystal oscillator is used for the dot clock.
character display.
5
HP5
0
(MSB)
1
4
HP4
0
1
3
HP3
0
1
2
HP2
0
1
HP1
0
1
0
HP0
0
(LSB)
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 × (2Σ 2nHPn)
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
5—
0
Display control setup
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
1
Erase display RAM (set to 3F hexadecimal)
500 s (It is executed in the DSPOFF state.)
1
OSCSTP
0
Do not stop the crystal oscillator and LC oscillator circuits.
Valid when character display is off in
1
Stop the crystal oscillator and LC oscillator circuits.
external synchronization mode.
0
SYSRST
0
Reset occurs when the CS1 pin is low, and
1
Reset all registers and turn the display off.
the reset is cleared when CS1 goes high.
Register content
DA0 to DA7
Register name
State
Function
Note
7—
0
Second byte identification bit
6
EGL
0
Border level 0 (VBK0)
Switches the border level
1
Border level 1 (VBK1)
5
NON
0
Interlaced (262.5H per field)
Switches between interlaced and
1
Noninterlaced (263H per field)
noninterlaced
4EG
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
2
BK0
characters, the blinking will be between
1
Blinking on
normal character and reversed character
display.
1RV
0
Reverse (character reversing) off
1
Reverse (character reversing) on
0
DSPON
0
Character display off
1
Character display on