common cathode 7 segment display pin diagram

COMMON CATHODE 7 SEGMENT DISPLAY PIN DIAGRAM HOW TO
COMMON CATHODE 7 SEGMENT DISPLAY PIN DIAGRAM PLUS

The individual segments are illuminated by applying a ground, logic “0” or “LOW” signal via a suitable current limiting resistor to the Cathode of the particular segment (a-g). The Common Anode (CA) – In the common anode display, all the anode connections of the LED segments are joined together to logic “1”. The individual segments are illuminated by application of a “HIGH”, or logic “1” signal via a current limiting resistor to forward bias the individual Anode terminals (a-g). The Common Cathode (CC) – In the common cathode display, all the cathode connections of the LED segments are joined together to logic “0” or ground. The difference between the two displays, as their name suggests, is that the common cathode has all the cathodes of the 7-segments connected directly together and the common anode has all the anodes of the 7-segments connected together. As each LED has two connecting pins, one called the “Anode” and the other “Cathode”, there are therefore two types of LED 7-segment display called: Common Cathode (CC) and Common Anode (CA). The display’s common pin is generally used to identify which type of 7-segment display it is. This then allows us to display each of the ten decimal digits 0 through to 9 on the same 7-segment display. So by forward biasing the appropriate pins of the LED segments in a particular order, some segments will be light and others will be dark allowing the desired character pattern of the number to be generated on the display. The other LED pins are connected together and wired to form a common pin. These LED pins are labeled from a through to g representing each individual LED. An additional 8th LED is sometimes used within the same package thus allowing the indication of a decimal point (DP) when two or more 7-segment displays are connected together to display numbers greater than ten.Įach one of the seven LEDs in the display is given a positional segment with one of its connection pins being brought straight out of the rectangular plastic package. Each of the seven LEDs is called a segment because when illuminated the segment forms part of a numerical digit (both Decimal and Hex) to be displayed. The 7-segment display consists of seven LEDs arranged in a rectangular fashion.

COMMON CATHODE 7 SEGMENT DISPLAY PIN DIAGRAM HOW TO

In this lesson you will learn how to use such a display to display characters. Different letters/numbers can be represented by connecting different pins on the display to the power source, thus turning on the LEDs in parallel. If you are out of microcontroller pins, consider using a 74HC595 Shift Register to drive the display.A 7-segment display is a device made up of seven LEDs connected in parallel that can be used for displaying numerals and some letters.

On the Raspberry Pi Pico: The PIO peripheral can take care of refreshing the display for you.

Luckily, there are libraries that can help:

Controlling the display in this mode is a bit tricky, as you'll need to continuously alternate between the different digits. So if you have 4 digits, you'll need 12 microcontroller pins in total.

COMMON CATHODE 7 SEGMENT DISPLAY PIN DIAGRAM PLUS

Turn a segment on by driving the corresponding segment on (or HIGH for the common cathode variant).įor multiple digits, you'll need 8 microcontroller pins for the segments and the dot plus one extra microcontroller pin for each digit. You can spare one pin (DP) if you don't use the dot LED. Each pin should be connected to a single segment through a resistor,Īnd the common pin should be connected to 5V (or GND if you are using the common cathode variant). Set to '1' to show the colon (clock mode)įor a single digit, you'll need 8 microcontroller GPIO pins. Setting common to cathode reverses this behavior, with the segment pins turning on when high. Segments are lit by driving their pins low. With the default common attribute setting of anode, the segment pins (A…G, DP, CLN) are connected to the cathode (negative side) of the LEDS, and the common pins (COM, DIG1…DIG4) are connected to the anode (positive side) of the LEDs. * COM is the common pin for a single digit 7-segment display. Seven segment LED display Pin names Name

Common cathode 7 segment display pin diagram