Datasheet
SCE5740, SCE5741, SCE5742, SCE5743, SCE5744, SCE5745
2006-03-30 9
Row Strobing
Multiplexer and Display Driver
The four characters are row multiplexed with RAM resident column
data. The strobe rate is established by the internal or external
MUX Clock rate. The MUX Clock frequency is divided by a 448
counter chain. This results in a typical strobe rate of 768 Hz. By
pulling the Clock SEL line low, the display can be operated from an
external MUX Clock. The external clock is attached to the CLK I/O
connection (pin 8). The maximum external MUX Clock frequency
should be limited to 3 MHz.
When a high speed external clock is used the frequency can be
further divided down by 16 by using the built in prescaler. In the
control word format data bit D4 is set high (D4=1). It is not recom-
mended to use the prescaler with the internal clock.
An asynchronous hardware Reset (pin 6) is also provided. Bring-
ing this pin low will clear the Character Address Register, Control
Word Register, RAM, and blanks the display. This action leaves the
display set at Character Address 0, and the Brightness Level set at
100%.
The user can activate four Control functions. These include: LED
Brightness Level, IC Power Down, Prescaler, or Display Clear.
OPCODEs and six bit words are used to initiate these functions.
The OPCODEs and Control Words for the Character Address and
Loading Column Data are shown in Tables „Load Character
Address“ (page 10) and „Load Column Data“ (page 10).
Control Word Format
0
4
5
6
Columns
1234
Load
Row Load Row 0
1
2
3
0
Columns
01
234
Columns
012
34
Load Row 1 Load Row 2 Load Row 5
Columns
Columns
0123
40
Columns
1234 01
Load Row 4Load Row 3
Columns
IDXX5184
234 01234
Load Row 6
6
5
3
4
2
0
1
6
5
3
4
2
0
1
6
5
3
4
2
0
1
6
5
3
4
2
0
1
6
5
3
4
2
0
1
6
5
3
4
2
0
1
Basic Instruction Set
Instruction Opcode Address/Data Comments
LCD 000 D4 D3 D2 D1 D0 Load Column Data
LDA 101 X X A2 A1 A0 Load Digit Address
SCL 110 PS B3 B2 B1 B0 Software Clear
LCWD 111 PS B3 B2 B1 B0 Load Control Word Data
IDCW5162
D7
1
D6
1
D5
1
D4
PS
D3
B3
D2
B2
D1
B1
D0
B0
6.6%
0
0
1
1
B2
100%
27%
40%
20%
13%
53%
0
0
1
BrightnessB1
0
B0
0
0
1
1
010
010
101
111 Blank Display &
Power Down
0
1
Full
Reduce to 12.5%
Pre-Scalar
MUX Clock/16
0 No Divide
1
by 16
PS
B3 Peak Current