fix functions arguments
extended sam3x GPIO from 16 to 31
fix GPIO_NUMOF to 32
add GPIOs
extend GPIO 16-31 for ArduinoDue/UDOO
fix white space at the end gpio_clear
- removed the __attribute__((naked)) from ISRs
- removed ISR_ENTER() and ISR_EXIT() macros
Rationale: Cortex-Mx MCUs save registers R0-R4 automatically
on calling ISRs. The naked attribute tells the compiler not
to save any other registers. This is fine, as long as the
code in the ISR is not nested. If nested, it will use also
R4 and R5, which will then lead to currupted registers on
exit of the ISR. Removing the naked will fix this.
