TCA8418: TCA8418

Thanks for your reply.
Any other IC that can support continues function. The TCA8418 is doing everything perfect except for 4 keys, i need continues press function as well. I tried to do it in programming but not able to do it. Maybe someone can help me to fix in programming otherwise, suggest me some other IC that can support complete keyboard function.
For now by using TCA8418, i don't need all keyboard function except if arrows keys function implement somehow.
Thanks

Hi Tyler Townsend

I got an idea if you can confirm me.

1. Key press
2. Even occur
3. perform function on key press continues
4. Key release
5. clear flag and interrupts

Is it possible that when a key press and release two even generate?

Thanks

Hi Tyler Townsend

Yes that's what i meant for point 3.
Can you tell me what register is responsible to generate event for both press and release with bit setting?
Should i read the voltage of interrupt pin because this is the only pin other than I2C connected with MCU?

Thanks
This is the code that print event table location when any key press but only when press, not release.

// Arduino I2C Library
#include <Wire.h>

// Keyboard Constants
#define KEYBOARD_ADDRESS 0x34
#define KEYBOARD_INT_PIN 1
#define KEYBOARD_EVENT_REGISTER 0x04
#define KEYBOARD_FLAG_REGISTER 0x02
#define KEYBOARD_KEY_DOWN 0x80
#define KEYBOARD_KEY_MASK 0x7F

// Debounce Constants
#define DEBOUNCE_DELAY 50 // Adjust this delay as needed

// Configuration commands (configures the 3x9 matrix as inputs with pull-ups, interrupts, etc.)
// For more information, refer to the code in the repository linked above
const uint8_t KEYBOARD_CONFIG_COMMANDS[] = {
  0x1D, 0x07,
  0x1E, 0xFF,
  0x1F, 0x03,
  0x01, 0xB9,
  0x02, 0x1F
};

// Define our functions before use
void keyboard_configure();
void keyboard_clearFlag();
uint8_t keyboard_getState();

// Debounce variables
uint8_t lastKeyCode = 0;
unsigned long lastKeyPressTime = 0;

// keyInt allows our event to ultimately be handled in the loop
volatile bool keyInt = false;

void setup() {
  Serial.begin(9600);
  Wire.begin();
  keyboard_configure();
  pinMode(KEYBOARD_INT_PIN, INPUT); // There is an external pull-up on the pin

  // Set up a falling edge pin interrupt on pin 1  
  attachInterrupt(digitalPinToInterrupt(KEYBOARD_INT_PIN), keyboard_ISR, FALLING); 
}

void loop() {
  if (keyInt) {
    uint8_t key_code = keyboard_getState(); // Get first keycode from FIFO
    if(key_code & KEYBOARD_KEY_DOWN) 
    {

      Serial.print(key_code & KEYBOARD_KEY_MASK);
      Serial.println(",");
    }

    keyboard_clearFlag();
    keyInt = false;
  }

  delay(10);
}

// WRITING I2C SLAVE
void keyboard_configure() {
  for (uint8_t i = 0; i < 7; i += 2) {
    Wire.beginTransmission(KEYBOARD_ADDRESS);
    Wire.write(KEYBOARD_CONFIG_COMMANDS[i]);
    Wire.write(KEYBOARD_CONFIG_COMMANDS[i + 1]);
    Wire.endTransmission();
  }
}

// READING I2C SLAVE
uint8_t keyboard_getState() {
  uint8_t key;
  Wire.beginTransmission(KEYBOARD_ADDRESS);
  Wire.write(KEYBOARD_EVENT_REGISTER);
  Wire.endTransmission();
  Wire.requestFrom(KEYBOARD_ADDRESS, 1); // request 1 byte from slave device 0x34
  while (Wire.available()) {
    // Slave may send less than requested
    key = Wire.read(); // Receive a byte as character
  }
  return key;
}

void keyboard_clearFlag() {
  Wire.beginTransmission(KEYBOARD_ADDRESS);
  Wire.write(KEYBOARD_FLAG_REGISTER); // Interrupt Status Register
  Wire.write(0x1F);
  Wire.endTransmission();
}

void keyboard_ISR() {
  keyInt = true;
}

Hi Tyler Townsend

Yes, I did the same and it worked.
Thanks for all your help.
Now it is working as a continuous key function.