HCMS-2819 Datasheet, PDF (7/12 Pages) AVAGO TECHNOLOGIES LIMITED – High Performance CMOS 5x7 AlphaNumeric InGaN Blue Display

Pixel Map
In a 4-character display, the 160-bits are arranged as 20
columns by 8 rows. This array can be conceptualized as
four 5x8 dot matrix character locations, but only 7 of the
8 rows have LEDs (see Figure 3 & 4). The bottom row (row
0) is not used. Thus, latch location 0 is never displayed.
Column 0 controls the left-most column. Data from Dot
Latch locations 0-7 determine whether or not pixels in
Column 0 are turned-on or turned off. Therefore, the lower
left pixel is turned-on when a logic high is stored in Dot
Latch location 3. Characters are loaded in serially, with the
left-most character being loaded first and the right-most
character being loaded last. By loading one character
at a time and latching the data before loading the next
character, the figures will appear to scroll from right to left.
Control Register
The Control Register allows software modification of
the IC’s operation and consists of two independent 7-bit
control words. Bit D₇ in the shift register selects one of the
two 7-bit control words. Control Word 0 performs pulse
width modulation brightness control, peak pixel current
brightness control, and sleep mode. Control Word 1 sets
serial/simultaneous data out mode, and external oscillator
prescaler. Each function is independent of others.
DATA TO
NEXT
CHARACTER
PIXEL
Figure 3. Pixel Map
DATA FROM
PREVIOUS
CHARACTER
ROW 7
ROW 6
ROW 5
ROW 4
ROW 3
ROW 2
ROW 1
ROW 0
(NOT USED)
DATA IN
CLK
CHIP
ENABLE
REGISTER
SELECT
RESET
L
H
DATA IN
DQ
CLR
RS
(LATCHED)
PRESCALE
VALUE
CONTROL
REGISTER
REFRESH
CONTROL
RST
÷8
H
OSC
L
H
OSCILLATOR
L
L
H
OSC
SELECT
RS (LATCHED)
HL
DATA OUT
SER/PAR
MODE
DATA
OUT
HL
CURRENT
REFERENCE
PWM BRIGHTNESS
CONTROL
DI
40 BIT
S.R.
DO
DI
40 BIT
S.R.
DO
DI
40 BIT
S.R.
DO
DI
40 BIT
S.R.
DO
DOT
REGISTERS
AND
LATCHES
V LED +
ANODE
CURRENT SOURCES
DOT
REGISTER
BIT # 159
ROW 7
0xx xx
xx x x x
xx x x x
ROW 1
x x x x x ROW 0 (NO LEDS)
COLUMN 0
CHAR 0
CHAR 1
CHAR 2
COLUMN 19
CHAR 3
GND (LED)
BLANK
Figure 4. Block diagram
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