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MicroPython driver for TM1638 dual quad 7-segment LED modules with switches
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tm1638.py

README.md

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.

demo

Examples

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

$ ampy put tm1638.py

Basic usage

# 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
tm.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"
Display Bin Hex Dec
0 0b00111111 0x3F 63
1 0b00000110 0x06 6
2 0b01011011 0x5B 91
3 0b01001111 0x4F 79
4 0b01100110 0x66 102
5 0b01101101 0x6D 109
6 0b01111101 0x7D 125
7 0b00000111 0x07 7
8 0b01111111 0x7F 127
9 0b01101111 0x6F 111
A 0b01110111 0x77 119
b 0b01111100 0x7C 124
C 0b00111001 0x39 57
d 0b01011110 0x5E 94
E 0b01111001 0x79 121
F 0b01110001 0x71 113
G 0b00111101 0x3D 61
H 0b01110110 0x76 118
I 0b00000110 0x06 6
J 0b00011110 0x1E 30
K 0b01110110 0x76 118
L 0b00111000 0x38 56
M 0b01010101 0x55 85
n 0b01010100 0x54 84
O 0b00111111 0x3F 63
P 0b01110011 0x73 115
q 0b01100111 0x67 103
r 0b01010000 0x50 80
S 0b01101101 0x6D 109
t 0b01111000 0x78 120
U 0b00111110 0x3E 62
v 0b00011100 0x1C 28
W 0b00101010 0x2A 42
X 0b01110110 0x76 118
y 0b01101110 0x6E 110
Z 0b01011011 0x5B 91
blank 0b00000000 0x00 0
- 0b01000000 0x40 64
* 0b01100011 0x63 99

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()

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

Connections

WeMos D1 Mini LED&KEY TM1638 Module
3V3 (or 5V) VCC
G GND
D7 (GPIO13) STB
D5 (GPIO14) CLK
D6 (GPIO12) DIO
STM32F407VET6 LED&KEY TM1638 Module
3V3 VCC
G GND
B4 STB
B5 CLK
B6 DIO

Links

License

Licensed under the MIT License.

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