gw1770df / micropython-tm1638

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

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

# 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

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

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

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

License

Licensed under the MIT License.