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Does AHB Specification prohibit a combo path from HTRANS to HREADYOUT?

alinx

Hello, 

I am trying to find information for AHB Specification (IHI0033C). Are AHB subordinates allowed to have a combo path from  HTRANS to HREADYOUT?

Thanks

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  • 0 in reply to Colin Campbell

    Hi . Thank you for your response. Yes, that makes sense. So, it looks like it is inferred from the AHB spec that there shouldn't be a path from HTRANS to HREADYOUT. In my case, HTRANS never really combinatorially changes the HREADYOUT in the same cycle - it is a synthesis path which exists from HTRANS to HREADYOUT (gated by another signal in the path which prevents a direct relationship in the same cycle). However, since the initiator also has a combo path from HREADYOUT to HTRANS, it creates a combo loop. 

     If I may ask, can an initiator have a combo path from HREADYOUT to HTRANS?

    Looking at the AHB Specification, it seems to be that the HTRANS driven out should be registered (depending on the HREADYOUT in the current cycle) - is that correct? Is there a special case where the initiator would want to change HTRANS combinatorially based on HREADYOUT input from the subordinate - is it allowed to do so as per the spec?

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  • 0 in reply to Colin Campbell

    Hi . Thank you for your response. Yes, that makes sense. So, it looks like it is inferred from the AHB spec that there shouldn't be a path from HTRANS to HREADYOUT. In my case, HTRANS never really combinatorially changes the HREADYOUT in the same cycle - it is a synthesis path which exists from HTRANS to HREADYOUT (gated by another signal in the path which prevents a direct relationship in the same cycle). However, since the initiator also has a combo path from HREADYOUT to HTRANS, it creates a combo loop. 

     If I may ask, can an initiator have a combo path from HREADYOUT to HTRANS?

    Looking at the AHB Specification, it seems to be that the HTRANS driven out should be registered (depending on the HREADYOUT in the current cycle) - is that correct? Is there a special case where the initiator would want to change HTRANS combinatorially based on HREADYOUT input from the subordinate - is it allowed to do so as per the spec?

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