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

AC Timing Characteristics Over Temperature Range (-40 to +85°C)
Timing
Diagram
Ref. Number
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Description
Register Select Setup Time to Chip Enable
Register Select Hold Time to Chip Enable
Rising Clock Edge to Falling Chip Enable Edge
Chip Enable Setup Time to Rising Clock Edge
Chip Enable Hold Time to Rising Clock Edge
Data Setup Time to Rising Clock Edge
Data Hold Time after Rising Clock Edge
Rising Clock Edge to DOUT ^[1]
Propagation Delay DIN to DOUT
Simultaneous Mode for one IC ^[1,2]
CE Falling Edge to DOUT Valid
Clock High Time
Clock Low Time
Reset Low Time
Clock Frequency
Internal Display Oscillator Frequency
Internal Refresh Frequency
External Display Oscillator Frequency
Prescaler = 1
Prescaler = 8
Symbol
t_rss
t_rsh
t_clkce
t_ces
t_ceh
t_ds
t_dh
t_dout
t_doutp
t_cedo
t_clkh
t_clkl
t_rstl
F_cyc
F_inosc
F_rf
F_exosc
Notes:
1. Timing specifications increase 0.3ns per pf of capacitive loading above 15pF.
2. This parameter is valid for Simultaneous Mode data entry of the Control Register.
4.5V<V_LOGIC<5.5V
Min Max
10
10
20
35
20
10
10
10
40
18
25
80
80
50
5
80
210
150
410
51.2 1000
410 8000
V_LOGIC = 3V
Min Max Units
10
ns
10
ns
20
ns
55
ns
20
ns
10
ns
10
ns
10
65 ns
30 ns
45 ns
100
ns
100
ns
50
ns
4 MHz
80
210 kHz
150 410 Hz
51.2 1000 kHz-
410 8000 kHz
Display Overview
The HCMS-281x blue LED displays are driven by on-board
CMOS ICs. The LEDs are configured as 5x7 font characters
and are driven in groups of 4 characters per IC. Each IC
consists of a 160-bit shift register (the Dot Register), two
7-bit Control Words, and refresh circuitry. The Dot Register
contents are mapped on a one-to-one basis to the display.
Thus, an individual Dot Register bit uniquely controls a
single LED.
8-character displays have two ICs that are cascaded. The
Data Out line of the first IC is internally connected to
the Data In line of the second IC forming a 320-bit Dot
Register. The display’s other control and power lines are
connected directly to both ICs.
Reset
Reset initializes the Control Register (sets all Control
Register bits to logic low) and places the display in the
sleep mode. The Reset pin shoud be connected to the
system power on reset circuit. The Dot Registers are not
cleared upon power-on or by Reset. After power-on, the
Dot Register contents are random; however, Reset will put
the display in sleep mode, thereby blanking the LEDs. The
Control Register and the Control Words are cleared to all
zeros by Reset.
To operate the display after being Reset, load the Dot
Register with logic lows. Then load Control Word 0 with
the desired brightness level and set the sleep mode bit
to logic high.
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