Seven Segment Display

The Seven Segment Display is an Arduino library designed to simplify the control of a seven-segment display. Its main purpose is to display decimal digits one at a time.

There are two types of seven-segment displays:

• Common Anode: The common pin is connected to a positive voltage.
• Common Cathode: The common pin is connected to ground.

Usage

An example of displaying digits from 0 to 9 and the decimal point.

#include "SevenSegmentDisplay.h"

// Set to SEVEN_SEGMENT_DISPLAY_COMMON_ANODE for a common anode configuration
const seven_segment_display_type_t commonPin = SEVEN_SEGMENT_DISPLAY_COMMON_CATHODE;

const uint8_t pinA = 23;
const uint8_t pinB = 22;
const uint8_t pinC = 15;
const uint8_t pinD = 17;
const uint8_t pinE = 4;
const uint8_t pinF = 21;
const uint8_t pinG = 19;

// Use 0xFF if the decimal point is not connected
const uint8_t pinDp = 18;

seven_segment_display_wired_t displayWired = {
  .common_type = commonPin,
  .pin_a = pinA,
  .pin_b = pinB,
  .pin_c = pinC,
  .pin_d = pinD,
  .pin_e = pinE,
  .pin_f = pinF,
  .pin_g = pinG,
  .pin_dp = pinDp,
};
SevenSegmentDisplay myDisplay(displayWired);

void setup() {
  Serial.begin(9600);
}

void loop() {
  /* Turn on the decimal point */
  myDisplay.dp(true);

  delay(1000);

  /* Turn off the decimal point */
  myDisplay.dp(false);

  /* Display each digit from 0 to 9 */
  for(uint8_t digit = 0; digit < 10; digit++) {
    myDisplay.display(digit);
    delay(1000);
  }

  /* Turn off the display */
  myDisplay.off();
}

Types

seven_segment_display_type_t

/* Enumeration for seven-segment display types */
typedef enum
{
    SEVEN_SEGMENT_DISPLAY_COMMON_ANODE = 0,
    SEVEN_SEGMENT_DISPLAY_COMMON_CATHODE
} seven_segment_display_type_t;

seven_segment_display_wired_t

/* Structure for the wiring of the display */
typedef struct
{
    seven_segment_display_type_t common_type; /* Type of common pin */
    uint8_t pin_a;                           /* Pin for segment A */
    uint8_t pin_b;                           /* Pin for segment B */
    uint8_t pin_c;                           /* Pin for segment C */
    uint8_t pin_d;                           /* Pin for segment D */
    uint8_t pin_e;                           /* Pin for segment E */
    uint8_t pin_f;                           /* Pin for segment F */
    uint8_t pin_g;                           /* Pin for segment G */
    uint8_t pin_dp;                          /* Pin for the decimal point (0xFF if not used) */
} seven_segment_display_wired_t;

#endif /* SEVEN_SEGMENT_DISPLAY_T_H */

Methods

display

/**
 * @brief               Displays a digit on the Seven Segment Display
 *
 * @param digit         digit to display (0-9).
 */
void display(uint8_t digit);

dp

/**
 * @brief               Turns the Decimal Point (DP) segment on or off.
 *
 * @param on            `true` to turn on the Decimal Point; `false` to turn it off.
 */
void dp(bool on);

off

/**
 * @brief              Turns off the display.
 */
void off();

FAQ

Other libraries display more characters; why doesn’t this one?

I believe the purpose of a seven-segment display is to show digits only. Other characters may not be displayed clearly enough to be considered.

Why are there so many comments in the source code?

Most comments might be seen as 'well, duh' remarks, but they are meant for beginner programmers.