HCMS-2819 Datasheet, PDF (8/12 Pages) AVAGO TECHNOLOGIES LIMITED – High Performance CMOS 5x7 AlphaNumeric InGaN Blue Display

Control Register Data Loading
Data is loaded into the Control Register, MSB first, accord-
ing to the procedure shown in Table 1 and Figure 2. First,
RS is brought to logic high and then CE is brought to logic
low. Next, each successive rising CLK edge will shift in the
data on the DIN pin. Finally, when 8 bits have been loaded,
the CE line is brought to logic high. When CLK goes to
logic low, new data is copied into the selected control
word. Loading data into the Control Register takes place
while the previous control word configures the displays.
Control Word 0
Loading the Control Register with D₇- = Logic Low selects
Control Word 0 (see Table 2). Bits D₀-D₃ adjust the display
brightness by pulse width modulating the LED on time,
while Bits D₄-D₅ adjusts the display brightness by chang-
ing the peak pixel current. Bit D₆ selects normal operation
or sleep mode.
Sleep mode (Control Word 0, bit D₆ = Low) turns off the
Internal Display Oscillator and the LED pixel drivers. This
mode is used when the IC needs to be powered up, but
does not need to be active. Current draw in sleep mode
is nearly zero. Data in the Dot Register and Control Words
are retained during sleep mode.
Control Word 1
Loading the Control Register with D₇ = Logic High selects
Control Word 1. This control Word performs two functions:
serial/simultaneous data out mode and external oscillator
prescale select (see Table 2).
Table 2. Control Shift Register
CONTROL WORD 0
L
D₆
D₅
D₄
D₃
D₂
D₁
D₀
↑
Bit D ₇
Set Low
to Select
Control
Word 0
PWM Brightness
Control
L
L
L
L
L
L
L
H
L
L
H
L
L
L
H
H
L
H
L
L
L
H
L
H
L
H
H
L
L
H
H
H
H
L
L
L
H
L
L
H
H
L
H
L
H
L
H
H
H
H
L
L
H
H
L
H
H
H
H
L
H
H
H
H
On-Time
Oscillator
Cycles
0
1
2
3
4
5
7
9
11
14
18
22
28
36
48
60
Duty
Factor
(%)
0
0.2
0.4
0.6
0.8
1.0
1.4
1.8
2.1
2.7
3.5
4.3
5.5
7.0
9.4
11.7
Relative
Brightness
(%)
0
1.7
3.3
5.0
6.7
8.3
11.7
15
18
23
30
37
47
60
80
100
Peak Current
Brightness
Control
HL
LH
LL
HH
Typical Peak
Pixel Current
(mA)
4.0
6.4
9.3
12.8
Relative Full
Scale Current
(Relative Brightness, %)
31
50
73 (Default at Power Up)
100
SLEEP MODE
L - DISABLES INTERNAL OSCILLATOR-DISPLAY BLANK
H - NORMAL OPERATION
CONTROL WORD 1
H
L
L
L
L
L
↑
Bit D ₇
Set High
to Select
Control
Word 1
Reserved for Future
Use (Bits D₂-D₆
must be set Low)
D₁
D₀
Serial/Simultaneous Data Out
L - D _out holds contents of Bit D ₇
H - D _out is functionally tied to D_in
External Display Oscillator Prescaler
L - Oscillator Freq ÷ 1
H - Oscillator Freq ÷ 8
8