If i am using a button conntected to pin 1 of GPIOA .. GPIOA_ENABLE_CLOCK(); GPIOA->MODER |=PIN_INPUT; GPIOA->PUPD |=NO_PULLUP_NO_PULL_DOWN; GPIOA->ODR |=(1 << 1); //this for external pull up resistor when i debug GPIOA IDR I found that IDR = 0x0000DFD9 . which means that pin 1 level is low , although i am connecting it to an external pull resistor ... why GPIOA->IDR is not 0x0000DFDB???why it is set to 0 pin 1?????
This is not an ARM question - and certainly doesn't belong in 'Infrastructure Solutions'!
You need to ask the Chip manufacturer: