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Konrad-Techtest's avatar
Konrad-Techtest
Icon for New Contributor rankNew Contributor
4 years ago

Avalon-ST SOP with Ready/backpressure

A simple question about the streaming interface. I can see examples of the relationship between 'Valid' and 'Ready' and successfully implemented some stuff, but only mid-packet.

What is the relationship between 'Start Of Packet' and 'Ready'?

If 'Ready' is low and a new packet presents on the interface, 'Valid' will signal high.

What does 'SOP' do?

Does it go high for one clock cycle or does it stay high until 'Ready' goes high?

I cannot seem to find a definition for this in the streaming spec.

3 Replies

  • sstrell's avatar
    sstrell
    Icon for Super Contributor rankSuper Contributor
    4 years ago

    startofpacket is always single-cycle. You would not assert it and mark it as valid if ready from the sink is not already asserted, and it's not held while waiting for ready to go high like when a host sees the waitrequest signal in a memory-mapped interface.

  • SyafieqS's avatar
    SyafieqS
    Icon for Super Contributor rankSuper Contributor
    4 years ago

    We do not receive any response from you to the previous reply, thus I will put this case to close pending. Please post a response in the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you with your follow-up questions.