SCDQ5541P/Q/R, SCDQ5542P/Q/R, SCDQ5543P/Q/R, SCDQ5544P/Q/R
2010-04-13
10
Row Strobe Example
The user can activate four Control functions. These include: LED
Brightness Level, Lamp Test, IC Power Down, or Display Clear.
OPCODEs and five bit words are used to initiate these functions.
The OPCODEs and Control Words for the Character Address and
Loading Column Data are shown in Instruction Set Table.
The user can select seven specific LED brightness levels. These
brightness levels (in percentages of full brightness of the display)
include: 100% (F0HEX), 53% (F1HEX), 40% (F2HEX), 27%
(F3HEX), 20% (F4HEX), 13% (F5HEX), and 6.6% (F6HEX). The
brightness levels are controlled by changing the duty factor of the
row strobe pulse.
The SCDQ554X offers a unique Display Power Down feature
which reduces I
CC to less than 50 A. When FFHEX is loaded the
display is set to 0% brightness and the internal multiplex clock is
stopped. When in the Power Down mode data may still be written
into the RAM. The display is reactivated by loading a new right-
ness Level Control Word into the display.
The Lamp Test is enabled by loading F8HEX into the serial shift
register. This Control Word sets all of the LEDs to a 53% bright-
ness level. Operation of the Lamp Test has no affect on the RAM
and is cleared by loading a Brightness Control Word.
The Software Clear (C0HEX) clears the Address Register and the
RAM. The display is blanked and the Character Address Register
will be set to Character 0. The internal counter and the Control
Word Register are unaffected. The Software Clear will remain
active until the next data input cycle is initiated.
Electrical & Mechanical Considerations
Interconnect Considerations
Optimum product performance can be had when the following
electrical and mechanical recommendations are adopted. The
SCDQ554XX’s IC is constructed in a high speed CMOS process,
consequently high speed noise on the SERIAL DATA, SERIAL
DATA CLOCK, and LOAD lines may cause incorrect data to be
written into the serial shift register. Adhere to transmission line ter-
mination procedures when using fast line drivers and long cables
(>10 cm).
Good digital grounds (pin 1) and power supply decoupling (pin 2)
will insure that I
CC (<350 mA peak) switching currents do not gen-
erate localized ground bounce. Therefore it is recommended that
each display package use a 0.1 F and 20 F capacitor between
V
CC and ground.
IDXX5182
Row 0
Row 1
Row 2
Row 3
Row 4
01 2 3 4
Columns
Load Row 0
Load
4
Row 4
Columns
1
0
2 3
Row 3
Row 1
Row 0
Row 2
Load Row 1
Columns
Row 4
1
0
2
4
3
Load Row 2
Row 2
Row 1
Row 3
Row 0
Row 4
0
Columns
2
13 4
Load Row 3
Row 0
Row 3
Row 1
Row 2
Row 4
Columns
01 2
4
3
Row 2
Row 1
Row 3
Row 0
Load Row 4
Row
Display Brightness
Op code
D7 D6 D5
Control Word
D4
D3
D2
D1
D0
Hex
Operation
Level
11
1
10
0
F0
100%
11
1
10
0
1
F1
53%
11
1
10
0
1
0
F2
40%
11
1
10
0
1
F3
27%
11
1
10
1
0
F4
20%
11
1
10
1
0
1
F5
13%
11
1
10
1
0
F6
6.6%
Power Down
Op code
D7 D6 D5
Control Word
D4
D3
D2
D1
D0
Hex
Operation
Level
11
1
11
1
FF
0%
brightness
Lamp Test
Op code
D7 D6 D5
Control Word
D4
D3
D2
D1
D0
Hex
Operation
Level
11
1
10
B
Lamp Test
(OFF)
11
1
11
0
F8
Lamp Test
(ON)
Software Clear
Op code
D7 D6 D5
Control Word
D4
D3
D2
D1
D0
Hex
Operation
Level
11
0
00
0
C0
CLEAR