Reading and writing pio(nios) in uclinux

Altera_Forum · ‎10-30-2010

hi,

I have uclinux on nios,

the memory is sdram,

but now i do not know how to read or write the pio(built in sopc) in uclinux.

can anybody help me?:)

thanks a lot!

my regards,

wangyipin

Altera_Forum · ‎10-31-2010

I'm not sure how it works in the latest versions of uClinux, but in the (old) version I use the build system generates a nios2_system.h header file from my .ptf that defines all my PIO addresses as a "np_pio" struct. It automatically names them na_<pio name>. You can then write/read to them directly from your application (assuming you aren't using an MMU). So, e.g., if you have a PIO named my_pio in SOPC builder then you can read/write it as follows:

#include "nios2_system.h"
  ...
  // Reads the PIO value.
  int currvalue = na_my_pio->np_piodata;
  // Writes a new value.
  na_my_pio->np_piodata = newvalue;
  ...

See the definition of the np_pio struct for info on more advanced features (e.g., bidirectional data, edge detection).

Altera_Forum · ‎10-31-2010

thanks Tristan,

i will try, and i know the header file is the point

Altera_Forum · ‎10-31-2010

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but now i do not know how to read or write the pio(built in sopc) in uclinux.

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In a device driver or in a user land program ?

Using NIOS with our without MMU ?

-Michael

Altera_Forum · ‎10-31-2010

In a user program without MMU.

What's the easiest way?

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In a device driver or in a user land program ?

Using NIOS with our without MMU ?

-Michael

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