Copyright © Matrix Technology Solutions Ltd.
4
General information
This board provides a quad seven-segment common
anode display, with an option to operate off only one
port using links. This display requires two E-blocks
ports to operate all four displays. If only one seven
segment display is needed then only one E-block port is
required and a jumper link of the board can be used to
permanently engage one of the display digits.
1. Features
• E-blocks compatible
• Quad common anode displays
Circuit description
The EB008 quad 7-segment display board circuit can be
observed on page 6.
To use the full quad 7-segment displays the board must
be connected to two I/O ports of an upstream board via
connectors J1 and J2. Also note that the link (on J4) MUST
NOT be connected. As there are not enough pins on the
connectors, each of the 4 7-segment displays are turned
on in sequence using connector J2 and the appropriate
data on connector J1 is displayed. Connector J2 [Pins
1 (left display) - 4 (right display)] are used to select
which of the four 7-seg display digits are active. The
signals from J2 are buffered by NPN transistors which
provide power for the anodes of each digit. The bits on
connector J1 [Pins 1-8] connect to the cathodes of each
segment and hence dictate which segments are lit. Note
that each cathode must go low for the segment to light.
For a program showing 4 digit numbers a multiplexing
algorithm is required.
The device can still operate using only one I/O port
connected to J1, but this only allows one (the far left)
display to be operational. Placing a link on J4 will
permanently power the anode of the left hand digit so
that only cathode data is needed for the individual LEDs
to illuminate. Again J1 dictates which segments are
illuminated.
The board is usually operated off a +5V supply. This can
easily be achieved by connecting a +5V supply via a wire
into the screw terminals.
The diagram below shows which pins illuminate which
corresponding segment in an individual digital display.
Please note that in the E-block acrhitecture than pin 1
will represent bit 0 of which ever port it is connected to.
1. 3.3V operation
This board is compatible with 3.3V systems.
• Operational link allows operation from only one I/O
port (two I/O ports required for full quad operation)
• Compatible with most I/O ports in the E-block range
• Ease to develop programming code using Flowcode
icons
• 3.3 voltage compatible
2. Block schematic
Not supplied.
a [Pin 1]
g [Pin 7]
d [Pin 4]
f [P
in 6]
e [P
in 5]
b [P
in 2]
c [P
in 3]
dp [Pin 8]