SCD55100A Datasheet, PDF (8/17 Pages) OSRAM GmbH – Dot Addressable Intelligent Display® Devices

SCD55100A, SCD55101A, SCD55102A, SCD55103A, SCD55104A
The following explains how to format the serial data to be loaded
into the display. The user supplies a string of bit mapped decoded
characters. The contents of this string is shown in Figure „Loading
Serial Character Data a“ (page 8). Figure „Loading Serial Charac-
ter Data b“ (page 8) shows that each character consist of six 8 bit
words. The first word encodes the display character location and
the succeeding five bytes are row data. The row data represents
the status (On, Off) of individual column LEDs. Figure „Loading
Serial Character Data c“ (page 8) shows that each 8 bit word is
formatted to include a three bit Operational Code (OPCODE)
defined by bits D7–D5 and five bits (D4–D0) representing Column
Data, Character Address, or Control Word Data.
Figure „Loading Serial Character Data d“ (page 8) shows the
sequence for loading the bytes of data. Bringing the LOAD line low
enables the serial register to accept data. The shift action occurs
on the low to high transition of the serial data clock (SDCLK). The
least significant bit (D0) is loaded first. After eight clock pulses the
LOAD line is brought high. With this transition the OPCODE is
decoded. The decoded OPCODE directs D4–D0 to be latched in
the Character Address register, stored in the RAM as Column
data, or latched in the Control Word register. The control IC
requires a minimum 600 ns delay between successive byte loads.
As indicated in Figure „Loading Serial Character Data a“ (page 8),
a total of 660 clock cycles (60-8 bit words) are required to load all
ten characters into the display.
The Character Address Register bits, D4–D0 (Table „Load Charac-
ter Address“ (page 9)) and Row Address Register bits, D7–D5
(Table „Load Column Data“ (page 9)) direct the Column Data bits,
D4–D0 (Table „Load Column Data“ (page 9)) to specific RAM loca-
tion. Table „Character ’D’“ (page 8) shows the Row Address for the
example character “D.” Column data is written and read asynchro-
nously from the 250 bit RAM. Once loaded the internal oscillator
and character multiplexer reads the data from the RAM. These
characters are row strobed with column data as shown in Figures
„Row and Column Location“ (page 9) and „Row Strobing“
(page 10). The character strobe rate is determined by the internal
or user supplied external MUX Clock and the IC’s ÷ 320 counter.
Character “D”
Op code
Column Data
Hex
D7 D6 D5 D4 D3 D2 D1 D0
C0 C1 C2 C3 C4
Row 0 0 0 0
1 1 1 1 0 1E
Row 1 0 0 1
1 0 0 0 1 31
Row 2 0 1 0
1 0 0 0 1 51
Row 3 0 1 1
1 0 0 0 1 71
Row 4 1 0 0
1 1 1 1 0 9E
Loading Serial Character Data
Example: Serial Clock = 5 MHz, Clock Period = 200 ns
660 Clock Cycles, 132 µs
a. Character 0 Character 1 Character 2 Character 3 Character 4 Character 5 Character 6 Character 7 Character 8 Character 9
66 Clock Cycles, 13.2 µs
b.
Character 0 Row 0 Column Row 1 Column Row 2 Column Row 3 Column Row 4 Column
Address
Data
Data
Data
Data
Data
11 Clock Cycles, 2.2 s
11 Clock Cycles, 2.2 s
Character Address OPCODE
Time
Column Data
OPCODE
Time
c.
D0
0
D1
0
D2
0
D3
0
D4
0
D5
1
D6
0
D7
0
Between
Loads
600 ns(min.)
D0 D1
C4 C3
D2
C2
D3
C1
D4
C0
D5
D6
Between
D7 Loads
600 ns(min.)
LOAD
Serial
Clock
Clock
Period
d.
DATA
D0 D1 D2 D3 D4 D5 D6 D7 Time between LOADS
t0
2006-02-20
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