HDSP-2533 Datasheet, PDF (11/15 Pages) AVAGO TECHNOLOGIES LIMITED – Eight Character 5 mm Smart Alphanumeric Display

Control Word Register
Figure 6 shows how to access the Control Word Register.
This is an eight bit register which performs five functions.
They are Brightness control, Flash RAM control, Blinking,
Self Test and Clear. Each function is independent of the
others. How­ever, all bits are updated during each Control
Word write cycle.
Brightness (Bits 0-2)
Bits 0-2 of the Control Word adjust the brightness of the
display. Bits 0-2 are interpreted as a three bit binary code
with code (000) corresponding to maximum brightness
and code (111) corresponding to a blanked display. In
addition to varying the display brightness, bits 0-2 also
vary the average value of I_DD. I_DD can be calcu­lated at
any brightness level by multiplying the percent bright-
ness level by the value of I_DD at the 100% brightness level.
These values of I_DD are shown in Table 2.
Flash Function (Bit 3)
Bit 3 determines whether the flashing character attribute
is on or off. When bit 3 is a “1,” the output of the Flash RAM
is checked. If the content of a loca­tion in the Flash RAM is
a “1,” the associated digit will flash at approximately 2 Hz.
For an external clock, the blink rate can be calculated by
dividing the clock frequency by 28,672. If the flash enable
bit of the Control Word is a “0,” the content of the Flash
RAM is ignored. To use this function with multiple dis­play
systems see the Reset section.
Blink Function (Bit 4)
Bit 4 of the Control Word is used to synchronize blinking of
all eight digits of the display. When this bit is a “1” all eight
digits of the display will blink at approxi­mately 2 Hz. The
actual rate is dependent on the clockfrequency. For an
external clock, the blink rate can be calculated by dividing
the clock frequency by 28,672. This function will override
the Flash function when it is active. To use this function
with multiple display systems see the Reset section.
RST CE WR RD
0 0 UNDEFINED
1
0
0
1
1 WRITE TO DISPLAY
0 READ FROM DISPLAY
1 1 UNDEFINED
CONTROL SIGNALS
FL A₄ A₃ A₂ A₁ A₀
110XX X
CONTROL WORD ADDRESS
D₇ D₆ D₅ D₄ D₃ D₂ D₁ D₀
C S S BL F B B B
0 0 0 100%
0 0 1 80%
0 1 0 53% BRIGHTNESS
0 1 1 40% CONTROL
1 0 0 27% LEVELS
1 0 1 20%
1 1 0 13%
1 1 1 0%
0 DISABLE FLASH
1 ENABLE FLASH
0 DISABLE BLINKING
1 ENABLE BLINKING
0 X NORMAL OPERATION; X IS IGNORED
1 X START SELF TEST; RESULT GIVEN IN X
X = 0 FAILED X = 1 PASSED
0 NORMAL OPERATION
1 CLEAR FLASH AND CHARACTER RAMS
CONTROL WORD DATA FORMAT
0 = LOGIC 0; 1 = LOGIC 1; X = DO NOT CARE
Figure 6. Logic levels to access the control word register.
Table 2. Current Requirements at Different Brightness Levels for All Colors Except AlGaAs

Symbol
D₂
D₁
D₀
I_DD (V)
0
0
0
0
0
1
%
V_DD = 5.0 V
Brightness
25°C Typ.
Units
100
200
mA
80
160
mA
0
1
0
53
106
mA
0
1
1
40
80
mA
1
0
0
27
54
mA
1
0
1
20
40
mA
1
1
0
13
26
mA
11