Forum Discussion

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

Qsys - Base Address Problem

Hello everyone,

i have created a qsys-system with a state machine working as an avalon memory mapped master and a pio working as an avalon memory mapped slave. The Master uses 32bit for addresses and 16bit data. The slave uses a 2 bit address and 8bit data. The pio slave is connected to leds.

Now the problem: If i use a base address for the slave like 00000000hex or 02000000hex than it seems to function as aspected but if i use a base address like 02000008hex nothing happen.

If i try to set the base address to an address like 02000001, i get an error that the base address cannot be at 02000001 (02000000 or 02000008 are acceptable).

Why can't i use base addresses like 02000008hex?

thanks and regards,

schlittk

19 Replies

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

    You modify QSYS : manually change base addresses for your Qsys component. QSYS can do this semi-automatically (menu ...). Why not.

    Did you regenerate Qsys ? YES, I think

    Did you recompile the whole project.

    I had similar when my Qsys was NOT in the root directory of my project (Nios II recognize an old qsys).

    Did you regenerate the associated BSP in NIOS II SBT ? In order to update the system.h (where "#define PIO_LED_BASE (0x02000008)"). I think your problem is here

    In your software, how do you write to your PIO ?

    by IOWR...(0x02000000, data)

    or IOWR_...(PIO_LED_BASE, data)

    You can let Quartus decide for base addresses except for Flash memory that should be locked at address 0x0000. Easier.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    Yes, i have regenerated QSYS and recompiled the quartus project.

    An old qsys can't be the error source because a change from working address 0x02000000 to working address 0x00000000 is not a problem.

    I don't use a NIOS. My system consist only of a state machine working as an avalon memory mapped master and a pio working as an avalon memory mapped slave. No more.

    For that reason there is no Software.

    The base address 0x02000008 was automatical generated by qsys but the components with lower addresses are removed for debug requirements. I plan to bring this components back to the design thats why i wanted to use this address.

    To use this address is not importend to me, more why i can't.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    I'm not sure whether you mean that i change the address i write to from 0x02000000 to 0x02000008 then yes i handle the offset.

    An another abnormal bahavior i have seen is when i set the base address for the pio in qsys to 0x02000008 and in my state machine Avalon Master the write destination address to 0x02000010 or 0x02000011 it seems to work correctly.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    Still looks to me that your state machine Avalon Master doesn't handle the offset 8 correctly. Maybe post the code?

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

    Looks OK to me.

    One observation: you use a 16-bit wide databus where the PIO expects a 32 bit databus. Maybe the fabric built by Qsys doesn't handle this well?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    So it is a custom PIO written by yourself?

    So far I have always used 32 bit transfers on the Avalon MM bus, even if addressing a register array of 8-bit objects