How to Use TM1638 display & switch: Examples, Pinouts, and Specs

The TM1638 is an integrated circuit designed by TM that combines an LED display driver and a key scan interface. This versatile component is widely used in microcontroller projects to control 7-segment displays and read input from a matrix of switches. Its ability to handle both display and input functions makes it an excellent choice for creating user interfaces in embedded systems.

• Digital clocks and timers
• Scoreboards
• User interfaces for embedded systems
• Home automation control panels
• Educational projects and prototyping

1. Power Supply: Connect the VDD pin to a 5V power supply and the GND pin to ground.
2. Data Communication: Connect the DIO, CLK, and STB pins to the corresponding pins on your microcontroller.
3. Display Connection: Connect the SEG1-SEG8 and GRID1-GRID8 pins to the 7-segment displays.
4. Key Scan: Connect the K1-K8 pins to the matrix of switches.

• Power Supply: Ensure a stable 5V power supply to avoid display flickering and erratic key inputs.
• Decoupling Capacitors: Place a 0.1µF capacitor close to the VDD and GND pins to filter out noise.
• Pull-up Resistors: Use pull-up resistors on the key scan lines to ensure reliable key detection.
• Serial Communication: Use appropriate timing for the serial communication to avoid data corruption.

#include <TM1638.h>

// Define the pins for the TM1638 module
#define DIO_PIN 2
#define CLK_PIN 3
#define STB_PIN 4

// Create an instance of the TM1638 class
TM1638 module(DIO_PIN, CLK_PIN, STB_PIN);

void setup() {
  // Initialize the module
  module.setupDisplay(true, 7); // Turn on display, set brightness to max (7)
}

void loop() {
  // Display a number on the 7-segment display
  module.setDisplayToDecNumber(12345678, 0x00, true);

  // Read the key inputs
  uint8_t keys = module.getButtons();
  
  // Check if any key is pressed
  if (keys != 0) {
    // Display the key value on the first digit
    module.setDisplayDigit(keys, 0, false);
  }

  delay(100); // Small delay to debounce keys
}

1. Display Flickering: This can be caused by an unstable power supply or insufficient current. Ensure a stable 5V supply and check the current rating.
2. No Display Output: Verify the connections, especially the DIO, CLK, and STB pins. Ensure the microcontroller is correctly programmed.
3. Erratic Key Inputs: This can be due to noise or lack of pull-up resistors. Add pull-up resistors to the key scan lines and use decoupling capacitors.

• Check Connections: Ensure all connections are secure and correctly mapped.
• Use a Multimeter: Measure the voltage levels at the VDD and GND pins to ensure proper power supply.
• Verify Code: Double-check the code for any logical errors or incorrect pin assignments.
• Consult Datasheet: Refer to the TM1638 datasheet for detailed information and advanced configurations.

The TM1638 display and switch module is a powerful and versatile component for creating interactive displays and user interfaces in microcontroller projects. By following the guidelines and best practices outlined in this documentation, users can effectively integrate the TM1638 into their projects and troubleshoot common issues with ease.