what is the protected type of shared variable?

[omidsht]

what is protected type ?

Hi , when i declare a shared variable like this :
shared variable o1 : bit :='0';
the warning says : the shared variable mut be of a protected type ?

what is protected type and what shall i di ?

 

[kvingle]

Re: what is protected type ?

take a look at this

http://support.aldec.com/KnowledgeBase/Article.aspx?aid=000696

 

[omidsht]

Re: what is protected type ?

take a look at this

http://support.aldec.com/KnowledgeBase/Article.aspx?aid=000696

can it be synthesized ?
it seems that ISE 10.1 and leonardo 2007 cant synthesize it ! what to do ?

 

[tkbits]

They don't synthesize because it requires adding arbitration logic.

Asynchronous arbitration can be done by a request-acknowledge protocol.

Synchronous arbitration can be performed by choosing ONE clock event for synchronizing ALL assignments to a specific variable. This is equivalent to creating a new process, and moving all assignments (to a specific variable) into that new process. In addition to adding a clock event, you would need to add conditions that select which assignment to perform.