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LCD sniffer for 12 pin custom LCD

VikramSaharan

Hello everyone 

I am trying to interface a TDS test pen with arduino. It has a 12 pin custom LCD. I want to get its LCD readings on serial monitor. I have no data sheet of the device under question.  Kindly help. 

  • 0

    Is there any other interface available on that device? Maybe an unpopulated connector on the PCB?
    Or do you know what microcontroller is used, and what pins of that controller go to the LCD?

    If the LCD has a driver IC, it may be (kind of) doable, because the signals will be digital.
    If the controller has the driver embedded (rare), the voltages on the interface pins may invert. Check that first with an oscilloscope.

    If you confirmed that the driver signals are digital 0/1 lines, you can start with the next activity:
    - use a digital analyser to capture communication, and try to relate it to what appears on the LCD. If you manage to solve that, you could build a gizmo, and write software to decode the LCD data into ascii and stream it over a serial.

  • +1 in reply to Jan Cumps

    This one has 12 pin lcd there is no any specification on main ic. A 8 pin another ic having marking ATMLH904 is also present 

  • 0 in reply to anniel747

    I connectd scl and sda and run I2C scanner on arduino i2c device foun at 0*50. when I run eprom read code 

    #include <Wire.h>

    #define EEPROM_ADDRESS 0x50  // The EEPROM I2C address

    void setup() {
      Serial.begin(9600);   // Start serial communication at 9600 baud
      Wire.begin();         // Initialize the I2C bus
     
      // Example: Write data to EEPROM and verify
      Serial.println("Writing 0x55 to address 0x01");
      writeEEPROM(0x01, 0x55);   // Write 0x55 to address 0x01
      delay(10);
     
      byte writtenData = readEEPROM(0x01);
      Serial.print("Data read from address 0x01: 0x");
      Serial.println(writtenData, HEX);  // Verify if data was written successfully
    }

    void loop() {
      Serial.println("Reading first 16 bytes of EEPROM:");
     
      // Read and display data from the first 16 addresses of the EEPROM
      for (int addr = 0; addr < 16; addr++) {  // You can increase the range to read more bytes
        byte data = readEEPROM(addr);
        Serial.print("Address 0x");
        Serial.print(addr, HEX);
        Serial.print(": Data 0x");
        Serial.println(data, HEX);
      }
     
      delay(5000);  // Delay 5 seconds before reading again
    }

    // Function to read a byte from a specific EEPROM address
    byte readEEPROM(int addr) {
      Wire.beginTransmission(EEPROM_ADDRESS);
      Wire.write((byte)addr);    // Specify the EEPROM address to read from
      Wire.endTransmission();
     
      Wire.requestFrom(EEPROM_ADDRESS, 1);  // Request 1 byte from EEPROM
     
      if (Wire.available()) {
        return Wire.read();      // Read and return the byte
      } else {
        return 0;  // Return 0 if no data is available
      }
    }

    // Function to write a byte of data to a specific EEPROM address
    void writeEEPROM(int addr, byte data) {
      Wire.beginTransmission(EEPROM_ADDRESS);
      Wire.write((byte)addr);  // Specify the EEPROM address to write to
      Wire.write(data);        // Write the data byte
      Wire.endTransmission();
      delay(10);               // EEPROM write requires a short delay
    }
    out put is   
    Address 0x3: Data 0xA0

    Address 0x4: Data 0xA0

    Address 0x5: Data 0xA0

    Address 0x6: Data 0xA0

    Address 0x7: Data 0xA0

    Address 0x8: Data 0xFF

    Address 0x9: Data 0xFF

    Address 0xA: Data 0xFF
  • 0 in reply to VikramSaharan

    I checked on PCB that eprom is connected with HOLD button to hold readings