Digital input pin voltage drop while using no pull config

[Kapil Rawat]

Hi I'm using nrf51822 with soft device 11.0 & want to read a 12 volt digital signal for this I'm converting 12v to 3v3 (4.5 & 1.5 Kohm Resistor) using voltage divider ckt but my voltage level is around 1v4 if I remove the pin from nrf then the voltage is around 3v3.

here is config: nrf_gpio_cfg_input(IGT_PIN, NRF_GPIO_PIN_NOPULL);

For reading: nrf_gpio_pin_read(IGT_PIN)

I Aslo try with pull up config but facing same problem

[Ole Bauck]

4.5 & 1.5 Mohm? or Kohm?

[Kapil Rawat]

4.5 & 1.5 K ohm resistor

[Ole Bauck]

Which pin do you use? Is this a custom board?

Is it different if you only run the config and reading in main (no other code)?

[Kapil Rawat]

@Ole Yes, it's custom board. After changing the pin (PO12 to PO16) system working fine.