Timing analysis of asynchronous bus peripherals
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From: primiano on 16 Jul 2010 06:40 Hello everyone, I have a (maybe) simple problem I don't know exactly how to face up. I am given a design (which is made by a third person) that realizes simple bus peripherals upon a Altera CPLD. The design is quite simple: the address bus along with the data bus and the READ signals are brought as inputs of the CPLD (outputs are not considered). There is a combinatorial network which, starting from the adresses bus and the READ signal, derives some internal Chip Select signals used to drive the Clock of internal FFD registries. Now, I am asked to perform timing analysis to such design to verify if it is feasible (I have the timing specs of the bus). How can I perform such kind of *asynchronous* analysis? I am used to analyze pure synchronous circuits, but this situation is totally different! Theoretically, I should verify that the propagation delay of the combinatorial decoding network is compatible with the timings of the FFDs, but actually I do not know exactly the timings of the FFD (I suppose they are not a fixed value but depend on the decisions of the place and route) Paradoxically, I would be able to verify timings if the FFDs were realized as physical chips OFF the CPLD (verifying that the pin-to-pin combinatorial delay is feasible according to the external FFD chips timings). How should I model such constrains when everything is modeled inside a CPLD design? I am currently using Quartus II tools. Thank you in advance, Primiano Tucci -- Primiano Tucci http://www.primianotucci.com --------------------------------------- Posted through http://www.FPGARelated.com |