TM1638plus RPI

Table of contents

• Overview
• Installation
• Test
• Software
• Hardware
• See Also

Overview

• Name: TM1638plus_RPI

• Author: Gavin Lyons.

• Description:

A Raspberry pi library to display data on a 8-digit TM1638 seven segment module. Dynamic install-able system level Raspberry Pi C++ library.

• Development Tool chain.
  1. Raspberry PI 3 model b
  2. C++, g++ (Debian 12.2.0)
  3. Raspbian , Debian 12 bookworm OS, , 64 bit.
  4. kernel : aarch64 Linux 6.1.0-rpi7-rpi-v8
  5. bcm2835 Library 1.73 dependency. Provides low level I2C bus, delays and GPIO control.

Installation

1. Install the dependency bcm2835 Library if not installed

   • The bcm2835 library is a dependency and provides delays and GPIO control.
   • Install the C libraries of bcm2835, Installation instructions here

2. Download the TM1638plus_RPI library

   • Open a Terminal in a folder where you want to download,build & test library
   • Run following command to download from github.

curl -sL https://github.com/gavinlyonsrepo/TM1638plus_RPI/archive/2.1.tar.gz | tar xz

3. Run "make" to run the makefile in base folder to install library, it will be installed to usr/lib and usr/include

cd TM1638plus_RPI-2.1
make
sudo make install

Test

Wire up your Display. Next step is to test LED display and the just installed library with an example file.

There are six examples files. The default example file is model 1 "hello world". To decide which one the makefile(In examples folder) builds simply edit "SRC" variable at top of the makefile(In examples folder). i.e. SRC=src/HELLOWORLD_Model1 in the "User SRC directory Option Section" at top of file. Pick an example "SRC" directory path and ONE Only. Comment out the rest.

List No	example file name	Model Num	Desc
1	HELLOWORLD_Model1	1	Hello world
2	HELLOWORLD_Model2	2	Hello world
3	HELLOWORLD_Model3	3	Hello world
4	TEST_Model1	1	test routines
5	TEST_Model2	2	test routines
6	TEST_Model3	3	test routines

Next enter the examples folder and run the makefile in THAT folder, This makefile builds the examples file using the just installed library. and creates a test exe file in "bin".

cd examples/
make
make run

Software

This library is a port of my Arduino Library. There at link below you will find the full documentation including the Application programming interface(API), which is similar to RPI version except ::

1. Examples files for Arduino are .ino files.
2. High freq data member flag is not needed in RPI library.
3. The text alignment enum has an extra enumerator for leading zeros.
4. Constructor has GPIO parameters in base class.
5. In file dependency graphs ,High level file includes will differ. eg "#include <bcm2835.h>" will be missing.
6. Model 3 code is in a separate file and separate sub-class of Model1.
7. Enumerators and constants are used instead of #defines

Arduino library github Link

Comms delay

Communications optional delay. It may be necessary to adjust the constant TMCommDelay in the TM1638plus_common.h file. It is Microsecond delay used in communications clocking, it is currently set to 1, It can be set to 0 or higher. On a different CPU Frequency to one tested, it may be necessary to increase/decrease this. The user can do this with the Getter method provided. TMCommDelayGet.

Hardware

Connections to RPI:

1. GPIO = STB = Strobe
2. GPIO = CLK = Clock
3. GPIO = DIO = Data input / output
4. GND
5. VCC 3.3V (or 5V see Note)

NOTE : If VCC is set to 5V, level shift GPIO to 3.3V or damage could result.

This library supports three variants of the TM1638, which for purposes of this documentation, will be named Model 1 ,Model 2 and Model 3. Pictured at from left to right.

Model No	Module Name	LEDS	Push buttons
Model 1	TM1638 LED & KEY	8 red only	8
Model 2	TM1638 KEYS, QYF	0	16
Model 3	TM1638 V1.3 or LKM1638	8 bi color, red and green	8

See Also

Combined Display library 'Display_Lib_RPI'