7-segment (FND)

Kaluma library for multi-digit 7-segment display (aka. FND - flexible numeric display). This support flexible number of digits, so it can be used for 1-digit, 2-digit, 3-digit, 4-digit and more.

Each segment is labeled as below:

    a
   ---
f |   | b
   -g-
e |   | c
   --- . dp
    d

Wiring

Here is a wiring example with a 4-digit 7-segment display (common-cathode type).

Raspberry Pi Pico	Resistor	FND (4-digit)
GP0	220(Ohm)	a
GP1	220(Ohm)	b
GP2	220(Ohm)	c
GP3	220(Ohm)	d
GP4	220(Ohm)	e
GP5	220(Ohm)	f
GP6	220(Ohm)	g
GP7	220(Ohm)	dp
GP21		COM1
GP20		COM2
GP19		COM3
GP18		COM4

Install

npm install https://github.com/niklauslee/7-segment

Usage

Here is an example for a 4-digit FND:

const FND = require('7-segment').FND;
const segments = [0, 1, 2, 3, 4, 5, 6, 7]; // 'a' to 'dp'
const digits = [21, 20, 19, 18]; // digit-0 to digit-3
const fnd = new FND(segments, digits);

fnd.display(25.4, 1);
fnd.on();

If you are using a common-anode type, create an instance with an option as below:

const fnd = new FND(segments, digits, {type: FND.ANODE});

If you are using 1-digit display and connect the common pin to GND (cathode) or 3V3 (anode), you can omit the digits parameter as below:

// common cathode
const fnd = new FND(segments);

// common anode
const fnd = new FND(segments, [], {type: FND.ANODE});

If you want to display non-numeric characters, you can use setDigit() with segment data.

// display 'E' on digit-0.
var seg = FND_SEG_A | FND.SEG_F | FND.SEG_E | FND.SEG_D | FND.SEG_G;
fnd.setDigit(seg, 0);

// or,
var seg = 0b01111001;
fnd.setDigit(seg, 0);

API

Class: FND

new FND(segments, digits[, options])

• segments <number[]> An array of pin numbers for segments (in the order of a, b, c, d, e, f, g, and dp).
• digits <number[]> An array of pin numbers for common-cathode(or anode) of each digits. The pin number should be in the order of digit-0 (left-most), digit-1, ..., digit-n (right-most).
• options <object> Options.
  • type <number> The type of FND. FND.CATHODE(=0) for common-cathode type or FND.ANODE(=1) for common-anode type. Default: 0.
  • fps <number> Number of frames per a second. It means how many shows all digits in a second. Greater value is more faster. Default: 60.

Create an instance of FND class.

setDigit(data, digit)

• data <number>
• digit <number>

Set the segment data at the digit in the internal buffer.

const FND = require('7-segment').FND;
// ...
// turn on 'b' and 'c' on digit-0.
var seg = FND.SEG_B | FND.SEG_C; 
fnd.setDigit(seg, 0);

display(value, fixed)

• value <number>
• fixed <number> Default: 0.

Display the number on the display with the size of fixed point. The number will not be displayed until you call on().

fnd.display(25.687, 0); // show `26`.
fnd.display(25.647, 1); // show `25.6`.
fnd.display(25.647, 2); // show `25.65`.

clear()

Clear the display. This means that clear the internal buffer.

on()

Turn on the display.

off()

Turn off the display.

FND.CATHODE

• <number> = 0

FND.ANODE

• <number> = 1

FND.SEG_A

• <number> = 0b00000001

FND.SEG_B

• <number> = 0b00000010

FND.SEG_C

• <number> = 0b00000100

FND.SEG_D

• <number> = 0b00001000

FND.SEG_E

• <number> = 0b00010000

FND.SEG_F

• <number> = 0b00100000

FND.SEG_G

• <number> = 0b01000000

FND.SEG_DP

• <number> = 0b10000000

FND.NUM

• <number[]>

An array of segment data for numbers from 0 to 9.