Your hardware and uClinux

Hi Ken !

I want to write a driver in uClinux ( from Microtronix plug-in in NIOS II IDE ), so i need a c example of using iow ( iowrite ) / ior ( ioread )

Please help me.

Thank you very much !

Linux doesn't make use of the IORD and IOWR commands that Altera defines. So you won't find any examples of those.

What I would recommend would be to take a look at some of the freebie sites with information on how to write device drivers. That's usually a good starting point.

For instance, I learned how to write my first modular driver using:

http://lwn.net/articles/driver-porting/ (http://lwn.net/articles/driver-porting/)

A few mods have to be made to some of the Makefile examples but all in all it worked pretty well.

A few things to note:

(1) any type of kernel work (device drivers, making mod's to the kernel, etc). cannot be performed from within Eclipse. It needs to be done from the commandline (Nios II SDK Shell)

(2) the kernel source code can be found at $KERNEL_PLUGIN/linux-2.6.x

(3) your kernel build directory can be found at $ECLIPSE_WORKSPACE/<project>/build

Hope this helps...

Hi Ken !

But, there should be a function to access a hardware on the board ( ie: 4 pins of speaker on the Altera Cyclone 1c12 eval board )

Please show me if there is

Thank you very much,

OneNet

All hardware in any Nios II based system can be accessed via simple memory reads/writes.

So, for example, if your hardware has registers at 0x00920830, then you can read from the first 4 bytes of your register by using something as simple as:

int *addr = 0x80920830;

int reg = *addr;

Notice that I turned on the high bit for the address of the registers. This bypasses the data cache so that I&#39;m guaranteed to receive current data. Writing is done in the same fashion.

Since access is so simple, there are no macro&#39;s to read and write from hardware for Linux as far as I know.