Avalon® Interface Specifications

ID 683091
Date 1/24/2022
Public

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3.5.2.4. waitrequestAllowance Compatibility for Avalon® -MM Host and Agent Interfaces

Avalon® -MM hosts and agents that support the waitrequest signal support backpressure. Hosts with backpressure can always connect to agents without backpressure. Hosts without backpressure cannot connect to agents with backpressure.
Table 11.  waitrequestAllowance Compatibility for Avalon-MM Hosts and Agents
Host and Agent waitrequestAllowance Compatibility

host = 0

agent = 0

Follows the same compatibility rules as standard Avalon-MM interfaces.

host = 0

agent > 0

Direct connections are not possible.

Simple adaptation is required for the case of a host with a waitrequest signal. A connection is impossible if the host does not support the waitrequest signal.

host > 0

agent = 0

Direct connections are not possible.

Adaptation (buffers) are required when connecting to a agent with a waitrequest signal or fixed wait states.

host > 0

agent> 0

No adaptation is required if the host's allowance <= agent's allowance.

If the host allowance < agent allowance, pipeline registers may be inserted.

For point-to-point connections, you can add the pipeline registers on the command signals or the waitrequest signals. Up to <d> register stages can be inserted where <d> is the difference between the allowances.

Connecting a host with a higher waitrequestAllowance than the agent requires buffering.