TM1638

Arduino library for modules based on the TM1638 controller.

The library provides simple functions for

• 8 seven-segment displays
• 8 LEDs
• 8 push buttons
• Display brightness control

The interface uses only three GPIO pins.

datasheet

https://fr.aliexpress.com/wholesale?SearchText=TM1638

Features

• Read individual buttons or all buttons at once
• Control individual LEDs or all LEDs
• Display hexadecimal digits (0-F)
• Display raw segment bitmaps
• Adjustable brightness
• Display on/off control
• Reset and hardware test functions

---

Wiring

TM1638	Arduino
STB	Any digital output
CLK	Any digital output
DIO	Any digital I/O

Example:

TM1638 display(2, 3, 4);
//              CLK DIO STB

---

Creating an object

#include <TM1638.h>

TM1638 display(2,3,4);

Constructor

TM1638(clkPin, dioPin, stbPin);

Parameter	Description
clkPin	Clock pin
dioPin	Data pin
stbPin	Strobe (Chip Select) pin

---

Public Methods

reset()

Clears everything.

• All digits off
• All LEDs off

display.reset();

---

displayVal()

Displays one hexadecimal digit.

display.displayVal(position, value);

Parameters

Parameter	Range
position	0-7
value	0-15

Example

display.displayVal(0,10);   // A
display.displayVal(1,15);   // F
display.displayVal(2,5);    // 5

---

displayDig()

Displays raw segment data.

display.displayDig(position, bitmap);

The bitmap uses

bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
 DP    G    F    E    D    C    B    A

Example

display.displayDig(0,0b01111111);

Lights every segment except the decimal point.

---

displayClear()

Turns off all seven-segment displays.

display.displayClear();

LEDs are not affected.

---

displayTurnOn()

Turns the display back on.

display.displayTurnOn();

---

displayTurnOff()

Turns off all display outputs without losing display memory.

display.displayTurnOff();

---

displaySetBrightness()

Sets display brightness.

display.displaySetBrightness(PULSE10_16);

Available brightness levels

Constant
PULSE1_16
PULSE2_16
PULSE4_16
PULSE10_16
PULSE11_16
PULSE12_16
PULSE13_16
PULSE14_16

Higher values produce a brighter display.

---

writeLed()

Controls one LED.

display.writeLed(1, ON);
display.writeLed(5, OFF);

Parameters

Parameter	Range
LED	1-8
State	ON/OFF or true/false

---

writeLeds()

Controls all LEDs simultaneously.

display.writeLeds(0b10101010);

Bit 0 controls LED1.

Bit 7 controls LED8.

---

getButton()

Reads one button.

if(display.getButton(S3))
{
    ...
}

Available button constants

S1
S2
S3
S4
S5
S6
S7
S8

Returns

true
false

---

getButtons()

Reads all eight buttons.

uint8_t keys = display.getButtons();

Bit mapping

Bit0 -> S1
Bit1 -> S2
Bit2 -> S3
Bit3 -> S4
Bit4 -> S5
Bit5 -> S6
Bit6 -> S7
Bit7 -> S8

---

test()

Hardware test.

display.test();

The function repeatedly flashes every LED and every segment.

Useful for verifying wiring.

---

Constants

Button constants

S1
S2
S3
S4
S5
S6
S7
S8

---

LED states

ON
OFF

---

Brightness

PULSE1_16
PULSE2_16
PULSE4_16
PULSE10_16
PULSE11_16
PULSE12_16
PULSE13_16
PULSE14_16

---

Example

#include <TM1638.h>

TM1638 display(2,3,4);

void setup()
{
    display.reset();

    display.displaySetBrightness(PULSE14_16);

    display.displayVal(0,1);
    display.displayVal(1,2);
    display.displayVal(2,3);
    display.displayVal(3,4);

    display.writeLed(1,ON);
}

void loop()
{
    if(display.getButton(S1))
    {
        display.writeLed(8,ON);
    }
    else
    {
        display.writeLed(8,OFF);
    }
}

License

MIT License.