Velleman VMP502, User Manual

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VMP502
V. 02
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25/10/2019 33 ©Velleman nv
6.10 Driving a 7-Segment Display by 74HC595
We will learn to use the 74HC595 to drive a 7-segment display to cycle a figure from 0 to 9.
Required Hardware
•
1 x Raspberry Pi
®
•
1 x breadboard
•
1 x 74HC595
•
1 x 7-segment display
•
3 x 1 k
Ω resistor
•
jumper wires as needed
7-segment displays can be categorized into two types: a common cathode and a common anode, depending on
the different light-emitting diode connections. They are widely used in electronic appliances, especially home
appliances such as air conditionings, water heaters, etc.
We use a common cathode 7-segment display, which connects all the LED cathodes to form a common cathode
(COM) electrode. It should be connected to ground. When the anode of an LED in a certain segment is at high
level, the corresponding segment will light. When it is at low, the segment will not light.