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Altera_Forum's avatar
Altera_Forum
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11 years ago

writing information into avalon slave in c

Hi,

I have a NIOS II which is connected to a vga component with avalon memory mapped slave.

In the VHDL entity, i have address, writedata, readdata, and chip select. the address base of the avalon memory mapped slave is 0x3008.

I am not sure how to write information into the memory mapped slave. The address is used so i can write data into different signals.

So far i have something like this in c:

# define x (char *) 0x3008

main(){

while(1)

*x=0x0F;

// whatever values i need to pass.

}

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    From NIOS you just treat it as if it is any other bit of memory and the processor will take care of the signalling (hence they are called memory-mapped).

    There are handy functions provided in the NIOS BSP that are useful when writing to slave devices such as:

    IOWR_32DIRECT(<base address>,<offset in bytes>,<32bit data>);

    IORD_32DIRECT(<base address>,<offset in bytes>);

    And similar ones for 8bit and 16 bit data.

    Alternative you can do something like:

    int main(){

    char* x = 0x3008;

    *x = 0x0F;

    }
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    --- Quote Start ---

    From NIOS you just treat it as if it is any other bit of memory and the processor will take care of the signalling (hence they are called memory-mapped).

    There are handy functions provided in the NIOS BSP that are useful when writing to slave devices such as:

    IOWR_32DIRECT(<base address>,<offset in bytes>,<32bit data>);

    IORD_32DIRECT(<base address>,<offset in bytes>);

    And similar ones for 8bit and 16 bit data.

    Alternative you can do something like:

    int main(){

    char* x = 0x3008;

    *x = 0x0F;

    }

    --- Quote End ---

    Thanks i got it working. Another question i have has regards to the altera monitor program. Has anyone used it?

    I'm trying to use the sleep function included from the unistd.h. However when i compile it tells me there is an undefined reference to sleep(). any ideas?

    ps. usleep() gives the same error