Part

Four-digit seven segment, multiplexed

Four digits on twelve legs: one digit at a time, fast enough that the eye sees all four.

12 pins
2 settings
In 1 project
In 1 lesson

Drawn live by the editor's own code, at the size you see it.

At a glance

The Four-digit seven segment, multiplexed in brief

What it is, and every setting the properties panel gives it.

The 5641AS is the bare four-digit seven-segment display in starter kits: four 0.56 inch digits on twelve legs, with no driver chip. Eight legs are the segments A to G and DP, each wired to that segment in all four digits, and four are the digit commons DIG1 to DIG4. The 5641AS is common cathode and the 5641BS common anode, a property. On an Uno the usual wiring is the segments on pins 2 to 9 through 220 ohm resistors and the commons on 10 to 13; on an ESP32 it is twelve free GPIOs, and 3.3 volts lights the segments more dimly. Only one digit can show at a time, so the sketch scans them. Mokxi models the 32 segments as LEDs and the eye as two poles of 15 milliseconds: a scan of 50 Hz or faster reads as four steady digits a quarter as bright, a slower one flickers, and changing the segments before switching the old digit off paints a faint ghost. The classic mistakes are resistors on the commons, which dims a digit as more segments light, and a delay() elsewhere in loop() that stalls the scan. Colon variants and brightness spread are not modeled.

Family: Displays
Pins: 12
common: cathode (or anode); cathode (a 5641AS, digits selected by pulling their common low) or anode (a 5641BS, digits selected by pulling their common high and segments lit by pulling them low).
color: red (or green, blue, yellow, white); the LED color.

Pins

12 pins

Named as the editor names them, so a wire lands where you expect it.

E
D
DP
C
G
DIG4
B
DIG3
DIG2
F
A
DIG1

How to use it

How to use a 4-digit 7-segment display with an Arduino

Segments A to G and DP go to pins 2 to 9, each through its own 220 ohm resistor, and the four digit commons, DIG1 to DIG4, go straight to pins 10 to 13. Each segment leg feeds that segment in all four digits, so only one digit can show at a time: the counter here shows each digit for four milliseconds and moves on, and the eye reads four steady digits.

On this common-cathode 5641AS a digit is on while its common is LOW and a segment lit while its leg is HIGH. Switch every common off before you change the segments, or the old digit shows a faint ghost of the new one; move that line in the sketch and look closely. A delay() anywhere else in loop() stops the scan and leaves one digit lit.

Part pin

Board pin

A, B, C, D, E, F, G, DP

Pins 2 to 9, each through 220 ohm

DIG1

Pin 10

DIG2

Pin 11

DIG3

Pin 12

DIG4

Pin 13

On an ESP32 the same scan runs on twelve free GPIOs; from 3.3 V the segments get less current through the same 220 ohm and look dimmer.

Arduino Uno: four-digit counterlive0.000 s 0.00x

Click to open it in the editor

This is the simulator itself, running here. Click anything to open it in the editor.

Open this project in the editor Read the full tutorial

One digit of the scan, from the four-digit counter

static void show(uint8_t digit, uint8_t pattern) {
  for (uint8_t d = 0; d < 4; d++) digitalWrite(DIGIT_PINS[d], HIGH);  // all off first
  for (uint8_t s = 0; s < 8; s++) {
    digitalWrite(SEGMENT_PINS[s], (pattern >> s) & 1 ? HIGH : LOW);
  }
  digitalWrite(DIGIT_PINS[digit], LOW);  // then this one on
  delay(4);
}

How it is modeled

What is true about the Four-digit seven segment, multiplexed, here

In its help article’s own words: what the simulation gets right, and where it stops.

Modeled

Each segment is the same diode as the LED. A common leg carries the current of every segment lit on it, which is eight segments' worth for an "8." and more than a microcontroller pin should sink: the textbook circuit puts a transistor on each common, and the part will tell you the current if you probe it. Put the resistors on the segment legs, not the commons, or the digit dims as more segments come on.