ST7920
Instructions
ST7920 offers basic instruction set and extended instruction set:
Instruction Set 1: (RE=0: Basic Instruction)
Code
Exec time
(540KHZ)
Inst.
Description
RS RW DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
Display
Clear
Fill DDRAM with "20H" and set DDRAM address counter (AC)
to "00H".
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
1
X
S
1.6 ms
72 us
72 us
Return
Home
Set DDRAM address counter (AC) to "00H", and put cursor
；
to origin the content of DDRAM are not changed
Entry Mode
Set
Set cursor position and display shift when doing write or read
I/D
operation
D=1: Display ON
C=1: Cursor ON
B=1: Character Blink ON
Display
Control
0
0
0
0
0
0
0
0
0
0
0
1
1
D
C
X
B
X
72 us
72 us
Cursor
Display
Control
Cursor position and display shift control; the content of
DDRAM are not changed
S/C R/L
DL=1 8-bit interface
Function
Set
0
X
DL=0 4-bit interface
0
0
0
0
1
1
DL
X
X
72 us
RE
RE=1: extended instruction
RE=0: basic instruction
Set
Set CGRAM address to address counter (AC)
CGRAM
Address.
Set
0
0
0
0
0
1
0
1
AC5 AC4 AC3 AC2 AC1 AC0 Make sure that in extended instruction SR=0 (scroll or
72 us
72 us
0 us
RAM address select)
0
Set DDRAM address to address counter (AC)
AC5 AC4 AC3 AC2 AC1 AC0
DDRAM
Address.
Read
AC6
AC6 is fixed to 0
Read busy flag (BF) for completion of internal operation, also
Busy Flag
(BF) & AC.
BF AC6 AC5 AC4 AC3 AC2 AC1 AC0
Read out the value of address counter (AC)
Write data to internal RAM
(DDRAM/CGRAM/GDRAM)
Read data from internal RAM
(DDRAM/CGRAM/GDRAM)
Write RAM
Read RAM
1
1
0
1
D7 D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
72 us
72 us
V4.0
16/49
2008/08/18
SITRONIX [ SITRONIX TECHNOLOGY CO., LTD. ]
