Specifications

SED1220
EPSON 4–21
SED1220
The cursor position indicates the position of address
counter.
Therefore, whenever moving the cursor, change
the address counter value using the RAM address
set command or the auto increment done by writing
the RAM data.
ISelective flashing symbol display is possible by
selecting (C, B) = (1, 0) and thus locating the
address counter to the position of the symbol register
through selecting (since the symbol is corresponding
to the character at each 5 dots).
(3) Power Save
This command is used to controlling the oscillation
circuit and setting or resetting the sleep mode.
PS = 0 : Power save off (reset)
1 : Power save on (set)
O = 0 : Oscillating circuit off (stop of
oscillation)
1 : Oscillating circuit on (oscilla
tion)
(4) Supply Control
This command is used for controlling operation of
the built-in power circuit.
P = 0 : Amplifying circuit off
1 : Amplifying circuit on
Note: The oscillation circuit must be turned on
for the amplitying circuit to be active.
C B Cursor display
0 0 Non-display
0 1 Non-display
1 0 Underbar cursor
1 1 Alternate display of display
characters in black and white.
The cursor position indicates the
position of address
COMMAND
Table 4 lists the commands. SED1220 identifies the data
bus signal using different combinations of A0 and WR
(E). High speed command interpretation and execution
are possible since only the internal timing is used.
• Command Overview
Instruction execution duration of dependents on the
internal process time of SED1220, therefore it is neces-
sary to provide a duration larger than the system cycle
time (t
CYC) between execution of two successive in-
struction.
• Description of Commands
(1) Cursor Home
This command presets the address counter to 30H
and moves the cursor, when it is present, to the first
digit of the first line.
(2) Display ON/OFF Control
This command performs on or off of display and
cursor setting.
Note: Symbols driven by COMSA and SEGSA – E
must be controlled through the static icon
RAM.
D = 0 : Display off
1 : Display on
B = 0 : Cursor blink off
1 : Cursor blink on
Blink displays characters in black and white,
alternately. The alternating display will be repeated
with approx. 1 second interval.
C = 0 : Display of cursor
1 : Does not display
Following table shows relationship between B and
C registers and the cursor.
Command type Command name A0 WR
Display control Cusor Home 0 0
instruction Display ON/OFF Control 0 0
Power control Power Save 0 0
Power Control 0 0
System set System set 0 0
Address control Address Set 0 0
instruction
Data input Data Write 1 0
instruction
A0 WR D7 D6 D5 D4 D3 D2 D1 D0
00 0001
****
∗ : Don't Care
A0 WR D7 D6 D5 D4 D3 D2 D1 D0
000011CB
*
D
(C, B) (0, 0) (1, 0) (1, 1)
f Blink
A0 WR D7 D6 D5 D4 D3 D2 D1 D0
000100
**
OPS
∗ : Don't Care
A0 WR D7 D6 D5 D4 D3 D2 D1 D0
0001010VC
VF
P