PIO set and clear bits

Make sure you enabled the "Enable individual bit setting/clearing" option in the pio properties in sopc builder.

Cris

Hi Cris!

Yes, thanks a lot for your quick reply. You are right: i did not enable the individual bit setting and clearing in the SOPC builder. I will report to this forum if this has the desired effect.

FredFlintstone

Ok, now the "Enable individual bit setting/clearing" option in the sopc builder is checked for my pio (it must be the right pio because i only have one).

I regenerated the BSP in the "Nios II 9.1 Software Build Tools for Eclipse". Afterwards i did a full rebuild.

Result: The macros IOWR_ALTERA_AVALON_PIO_SET_BITS() and

IOWR_ALTERA_AVALON_PIO_CLEAR_BITS() still do not work. From the debug messages i can see that they must have been called ("Msg = set_bits", "Msg = clear_bits").

Is there any possibility to check if the pio now really has the set/clear registers?

My source code:

# include "sys/alt_stdio.h"# include "sys/alt_sys_wrappers.h"# include "system.h"# include "altera_avalon_pio_regs.h"# include "Msg.h"# include "Str.h"# include "io.h"

static char c;

static int n;

int main()

{

alt_putstr("\n\nNios ii speaking...\n");

/* Event loop never exits. */

while (1)

{

n = read(0,&c,1); // read one char from stdin/0

if( n == 1 )

{

Msg_DataIn(c);

}

if( Msg_Available() )

{

alt_printf("The message is: %s\n",Msg());

if( Str_Equal(Msg(),"set_bits") )

{

alt_putstr("Msg = set_bits\n");

IOWR_ALTERA_AVALON_PIO_SET_BITS(PIO_0_BASE, 0x0003FFFF);

}

if( Str_Equal(Msg(),"clear_bits") )

{

alt_putstr("Msg = clear_bits\n");

IOWR_ALTERA_AVALON_PIO_CLEAR_BITS(PIO_0_BASE, 0x0003FFFF);

}

if( Str_Equal(Msg(),"on") )

{

alt_putstr("Msg = on\n");

IOWR_ALTERA_AVALON_PIO_DATA(PIO_0_BASE, 0x0003FFFF);

}

if( Str_Equal(Msg(),"off") )

{

alt_putstr("Msg = off\n");

IOWR_ALTERA_AVALON_PIO_DATA(PIO_0_BASE, 0x00000000);

}

Msg_Clear();

// alt_putchar(c);

// write(1,&c,1); // write one char to stdout/1

}

}

return 0;

}

I never used this feature, anyway you can check system.h file. I think you should have this define: # define PIO_0_BIT_MODIFYING_OUTPUT_REGISTER 1

It would be 0 if individual set/clear is not enabled.

Enabling individual set/clear in sopc builder, generates two extra pio registers at offset 4 and 5.

You'll find complete (and more reliable than mine...) information in Nios reference handbook, vol 5, chapter 9

http://www.altera.com/literature/hb/nios2/n2cpu_nii51007.pdf

Cris

Another idea; probably you already tried it.

Did you try to set/clear a single bit instead of the complete 18bit pio?

Hi Chris!

Ok, i checked this my system.h file:

Before enabling "Enable individual bit setting/clearing" ==># define PIO_0_BIT_MODIFYING_OUTPUT_REGISTER 0

Now after enabling "Enable individual bit setting/clearing" ==># define PIO_0_BIT_MODIFYING_OUTPUT_REGISTER 1

So the registers for setting and clearing the pio should be there...

> Did you try to set/clear a single bit instead of the complete 18bit pio?

Yes, i also tried this but it did not have any effect.

FredFlintstone

I tried with pio on my system and the bit set/clear feature works.

I only had to enable individual bit setting/clearing in sopc builder.

Hi Cris!

Thank you for your efforts! It still does not work for me. I think i will try to rebuild the nios in sopc builder from scratch.

But just another though: Could it be that the IOWR_ALTERA_AVALON_PIO_SET_BITS() and

IOWR_ALTERA_AVALON_PIO_CLEAR_BITS() macro do not work because i derived my project from the "Hello World Small" template?

Regards

FredFlintstone

--- Quote Start ---

Could it be that the IOWR_ALTERA_AVALON_PIO_SET_BITS() and

IOWR_ALTERA_AVALON_PIO_CLEAR_BITS() macro do not work because i derived my project from the "Hello World Small" template?

Regards

FredFlintstone

--- Quote End ---

I don't think so. I can't see any relation with the template. No OS or drivers are involved. This is only a matter of writing a register.

Further suggestions:

- try to write the actual set/clear registers (base+4, base+5) instead of using the macros

- make sure you are loading the correct fpga configuration which includes the sopc where you enabled the bit set feature.

- try with another pio port, 8bit wide (if you don't have free fpga pins for the new pio, add one more pio for reading the status with a loopback )

Hi Cris!

Yes, now it works (The macros IOWR_ALTERA_AVALON_PIO_SET_BITS() and

IOWR_ALTERA_AVALON_PIO_CLEAR_BITS() work). After i have recreated my nios with sopc builder from scratch it suddenly worked. No change to my c-code. My pio still has a width of 18 bit.

Just to sum it up for the thread followers:

The macros IOWR_ALTERA_AVALON_PIO_SET_BITS() and

IOWR_ALTERA_AVALON_PIO_CLEAR_BITS() did not work because i missed to enable the individual bit setting/clearing when i set up the pio in the sopc builder. After enabling it and a nios rebuild the macros work fine.

Thanks for that advice Cris!

Best regards

FredFlintstone