2–10
SCD5580/5581/5582/5583/5584
Socket manufacturers are Aries Electronics, Inc., French-
town, NJ; Garry Manufacturing, New Brunswick, NJ; Robin-
son-Nugent, New Albany, IN; and Samtec Electronic
Hardward, New Albany, IN.
For further information refer to Appnote 22 in the current Sie-
mens Optoelectronic Data Book.
Optical Considerations
The 0.145" high character of the SCD558X gives readability
up to eight feet. Proper lter selection enhances readability
over this distance.
Using lters emphasizes the contrast ratio between a lit LED
and the character background. This will increase the dis-
crimination of different characters. The only limitation is cost.
Take into consideration the ambient lighting environment for
the best cost/benet ratio for lters.
Incandescent (with almost no green) or uorescent (with
almost no red) lights do not have the at spectral response of
sunlight. Plastic band-pass lters are an inexpensive and
effective way to strengthen contrast ratios. The SCD5580/2
are red/high efciency red displays and should be matched
with long wavelength pass lter in the 570 nm to 590 nm
range. The SCD5583/4 should be matched with a yellow-
green band-pass lter that peaks at 565 nm. For displays of
multiple colors, neutral density grey lters offer the best com-
promise.
Additional contrast enhancement is gained by shading the
displays. Plastic band-pass lters with built-in louvers offer
the next step up in contrast improvement. Plastic lters can
be improved further with anti-reective coatings to reduce
glare. The trade-off is fuzzy characters. Mounting the lters
close to the display reduces this effect. Take care not to
overheat the plastic lter by allowing for proper air ow.
Optimal lter enhancements are gained by using circular
polarized, anti-reective, band-pass lters. The circular polar-
izing further enhances contrast by reducing the light that
travels through the lter and reects back off the display to
less than 1%.
Several lter manufacturers supply quality lter materials.
Some of them are: Panelgraphic Corporation, W. Caldwell,
NJ; SGL Homalite, Wilmington, DE; 3M Company, Visual
Products Division, St. Paul, MN; Polaroid Corporation, Polar-
izer Division, Cambridge, MA; Marks Polarized Corporation,
Deer Park, NY, Hoya Optics, Inc., Fremont, CA.
One last note on mounting lters: recessing displays and
bezel assemblies is an inexpensive way to provide a shading
effect in overhead lighting situations. Several Bezel manufac-
turers are: R.M.F. Products, Batavia, IL; Nobex Components,
Grifth Plastic Corp., Burlingame, CA; Photo Chemical Prod-
ucts of California, Santa Monica, CA; I.E.E.–Atlas, Van Nuys,
CA.
Microprocessor Interface
The microprocessor interface is through the serial port, SPI
port or one out of eight data bits on the eight bit parallel port
and also control lines SDCLK and LOAD.
Power Up Sequence
Upon power up display will come on at random. Thus the dis-
play should be reset at power-up. The reset will set the
Address Register to Digit 0, User RAM is set to 0 (display
blank) the Control Word is set to 0 (100% brightness with
Lamp Test off) and the internal counters are reset.
Figure 12. SCD Interface to Siemens/Intel 8031 Microprocessor (using serial port in mode 0)
VCC
U1
8031
9 RST
18
19
XTAL2
XTAL1
40
RXD
TXD
10
11
28
27
23
20 19 16
15 28
27
23
2019 16
15
1 2
6
9
6
9
13 14
DATA
SCD
SLAVE
MASTER
LOAD
SD
CLK
SD
CLK
22
F
TAN
.01
F
P3.7 17
P3.3 13
P3.4 14
+