Changing waitrequestallowance on the EMIF's slave Avalon Interface

[Gsus]

Hi,

We need a waitrequest allowance of 1 for the slave Avalon interface on the EMIF IP. Changing this value in the Signals & Interfaces tab under the Component instantiation window for both the master and slave interfaces and running Synch System Info, resets the waitrequestallowance to 0. Generating the HDL output without synchronizing the system info throws a warning pointing out the mismatch on waitrequestallowance between our definitions on Platform Designer and the IP files.

Trying to modify this value by opening the IP in Platform designer is also useless. These parameters are grayed out and trying to use the Interface Requirements tab is also a dead end since the user requirements are synchronized with the current system parameter values (which pretty much turns the Interface Requirements useless, except for pointing out the differences in the current system parameters vs what you wan't but apparently won't get).

Is the functionality for a waitrequestallowance setting different than 0 implemented in the EMIF IP?

Regards

[NurAida_A_Intel]

Dear Gsus,

By default the value of waitrequestAllowance is set to 0. But user can change the setting to 1 and 2 as well. However, waitrequestAllowance equals 2 is not recommended due to timing concern. For more details, you may refer to this Avalon Specification handbook on Chapter "3.5.2. Transfers Using the waitrequestAllowance Property" (page 23).

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/manual/mnl_avalon_spec.pdf

Thanks.

Regards,

NAli1

[Gsus]

Hi NAli1,

Do you have a specific procedure to do this change? As I said before, the option for changing this property is grayed out in the IP. Creating a new EMIF IP from scratch also shows this property read only. Modifying this value in Qsys (which is the only instance I've found the option is not grayed out) doesn't propagate to the IP and is reset to 0 after a synch system info. Should I modify a configuration file to do this?

Thanks,

Gsus

[sstrell · Accepted solution]

Since the EMIF is an IP, it may not allow you to change the waitrequest allowance. You can see it on the Signals & Interfaces tab because this is common for all Avalon interfaces, but the IP may be overriding it.

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