TCA8418E：To use gpio mode, what steps are required to configure

What is the value in register 0x1E? What do you read from register 0x15, and what did you expect?

The value read out is 0xff, we used COL1-4, COL5-7 is not used, connected to the pull-up resistor, ready to be used as a gpio, want to read the gpio status of COL7，For example, COL7 is currently in the pull-up state, and the read state should be 1, if the pull-up resistor is not connected, the read state should be 0

If I want to read the gpio status, what configuration do I need to do

What is the value in register 0x1E?

The value of 0x1E is 0xFF

This configures the first eight columns for keypad mode. To get GPIOs, set 0x1E to 0x00.

we used COL1-4, COL5-7 is not used, connected to the pull-up resistor, ready to be used as a gpio, want to read the gpio status of COL7，For example, COL7 is currently in the pull-up state, and the read state should be 1, if the pull-up resistor is not connected, the read state should be 0,If we want this result, what should we do

Clear the corresponding bits in the KP_GPIOx registers. (This is the default.) Clear the corresponding bits in the GPIO_DIRx registers. (This is the default.)

How do I clear this? What should I do after clearing? How can I read COL7 when used as a gpio. If the hardware is connected to a pull-up resistor, the read is 1 and the ground read is 0. Which register is used to read

These bits are cleared by default; you do not need to do anything. (But you can write a zero to these registers.)

To read the current state of the COL0..7 pins, read register 0x15.

Are you sure that your I²C communication works correctly? Does your code check for NACK? When you read register 0x1E after powering up, is it zero?

I used to write the value to register 0x1E when the driver was just loaded. I also read it and it was written in. I2c was for communication. I read the 0x15 register but it was 0x00.

I also tried to write the 0x24 register as output to read, but the result is still the same as 0x00

What is the voltage at the pin?