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MicroPython TM1638 LED Driver

A MicroPython library for LED&KEY modules with 8x 7-segment decimal LED modules, 8x individual LEDs and 8x switches using the TM1738 LED driver.

Examples

Copy the file to your device, using ampy, rshell, webrepl or compiling and deploying. eg.

$ ampy put tm1638.py

Basic usage

# TinyPICO / ESP32
import tm1638
from machine import Pin
tm = tm1638.TM1638(stb=Pin(5), clk=Pin(18), dio=Pin(23))

# Wemos D1 Mini / ESP8266
import tm1638
from machine import Pin
tm = tm1638.TM1638(stb=Pin(13), clk=Pin(14), dio=Pin(12))

# STM32F407VET6
import tm1638
from machine import Pin
tm = tm1638.TM1638(stb=Pin('B4'), clk=Pin('B5'), dio=Pin('B6'))

# every 2nd LED on
tm.leds(0b01010101)

# all LEDs off
tm.leds(0)

# segments
tm.show('cool')
tm.show('abcdefgh')
tm.number(-1234567)
tm.number(1234)
tm.number(5678, 4)
tm.hex(0xdeadbeef)

# dim both LEDs and segments
tm.brightness(0)

# all LEDs and segments off
tm.clear()

# get which buttons are pressed on LED&KEY module
tm.keys()

# get which buttons are pressed on QYF-TM1638 module
tm.qyf_keys()

For more detailed examples, see examples.

Seven Segment Font

They are called 7-segment displays as there are 7 LEDs for each digit (segment). One byte (7 lower bits) for each segment. The 8th bit (MSB) is for the decimal point on each segment.

      A
     ---
  F |   | B
     -G-
  E |   | C
     ---  * H
      D

  HGFEDCBA
0b01101101 = 0x6D = 109 = show "5"

Methods

Power up, power down or check status.

power(val=None)

Get or set brightness.

brightness(val=None)

Write zeros to each address.

clear()

Write to all 16 addresses from a given position. Order is left to right, 1st segment, 1st LED, 2nd segment, 2nd LED etc.

write(data, pos=0)

Set the value of a single LED.

led(pos, val)

Set all LEDs at once. LSB is left most LED. Only writes to the LED positions (every 2nd starting from 1).

leds(val)

Set one or more segments at a relative position. Only writes to the segment positions (every 2nd starting from 0).

segments(segments, pos=0)

Return a byte representing which keys are pressed. LSB is SW1.

keys()

Return a 16-bit value representing which keys are pressed. LSB is SW1.

qyf_keys()

Convert a single hex digit (0x00-0x0f) to a segment.

encode_digit(digit)

Convert a string to a list of segments. Dots are merged with the previous character.

encode_string(string)

Convert a single character to a segment.

encode_char(char)

Display a number in hexadecimal format 00000000 through FFFFFFFF, right aligned, leading zeros.

hex(val)

Display a numeric value -9999999 through 99999999, right aligned.

number(num)

Display a temperature -9 through 99 followed by degrees C.

temperature(num, pos=0)

Displays a relative humidity -9 through 99 followed by RH.

humidity(num, pos=4)

Displays as much of a string as will fit.

show(string, pos=0)

Display a string, scrolling from the right to left, speed adjustable. String starts off-screen right and scrolls until off-screen left at 4 FPS by default.

scroll(string, delay=250)

Parts

• WeMos D1 Mini $6.36 AUD
• LED&KEY TM1638 Module $2.30 AUD
• Female-Female Dupont wires $0.62 AUD

Connections

Links

• WeMos D1 Mini
• micropython.org
• TM1638 datasheet
• Titan Micro TM1638 product page
• Adafruit Ampy

License

Licensed under the MIT License.