SOPC Warning

[Altera_Forum]

Hello, please can anybody explain me, what does mean this SOPC warning? I can´t find it anywhere. 

 Warning: user_rapidio_SOPC_0_0.sys_mnt_s: blok_IOMasterWindow_0.write must be the only master because waitrequest is missing.  I use SOPC 10.1 Build 153   Thank you very much.

[Altera_Forum]

It looks like you generated a custom SOPC builder symbol using the sopc builder editor (which incidentally is a piece of crap) that contains an Avalon-MM io Slave - you either misdefined the ports to the object or failed to define a waitrequest to for the symbol that is needed (or the POS editor didn't work in its entirety and failed to either update an interface properly or left the remnants of an edited interface there. 

 When using the editor, I typically import a design and write out "strawman" files - something that is a start to show you interface format, naming conventions etc, but you know that the file is incomplete - I then edit the file using an external editor and re-import it, using the GUI editor to prune unused interfaces (since somehow it keeps a memory of ports no longer on your component) Hope this helps... crayner

[Altera_Forum]

..... what the message really means is that you have a master that lacks the waitrequest signal. Waitrequest is used to tell the master that the fabric is not ready to accept a read or write request. Reasons for this blocking could be that some other master is accessing the slave or the slave can't accept any more transfers. 

 The Avalon spec states that waitrequest is a mandatory signal for any master in your system: http://www.altera.com/literature/manual/mnl_avalon_spec.pdf  So if you hooked up this problematic master to a slave that already has another master connected to it then the fabric would have no way to tell the master lacking the waitrequest signal to hold off. If you are familiar with shared bus interconnects waitrequest is very similar to ~master_grant.

[Altera_Forum]

I had signal waitrequest_n in my avalon interface of "problematic" master component, so I was suprised, that this warning SOPC BUILDER call. I solved this problem by changing the type of this signal in SOPC builder component editor to waitrequest (positive logic). 

Thank you for your answers.