Very simple question about PIO

Question

typedef volatile struct

{

int np_piodata; // read/write, up to 32 bits

int np_piodirection; // write/readable, up to 32 bits, 1->output bit

int np_piointerruptmask; // write/readable, up to 32 bits, 1->enable interrupt

int np_pioedgecapture; // read, up to 32 bits, cleared by any write

} np_pio;

can you explain me how to use PIO register...for example if i want to read

a pio register... i do PIO->np_piodata..

Why does the function of " np_piodirection"

altera_forum · Answer

Hi,

in general if you want learn something about the peripherials, you might want to read "Altera Embeeded Peripherals Handbook" (n2cpu_nii5v3.pdf).

However you should use inl(...) for reading and outl(...) for writing the hardware register.

Accessing the hardware register with such a structure is a "Nios speciality".

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