RapidIO II Intel® FPGA IP User Guide

ID 683444
Date 9/28/2020
Public
Document Table of Contents

4.3.5.1. Transaction ID Ranges

To limit the required storage, the RapidIO II IP core shares a single pool of transaction IDs among all destination IDs, although the RapidIO specification allows for independent pools for each Source-Destination pair.

To simplify the routing of incoming ftype=13 response packets, the IP core assigns an exclusive range of transaction IDs to each of the instantiated Logical layer modules. This set of assignments simplifies response routing, but places a constraint on your design. If you implement custom logic that communicates to the RapidIO II IP core through the Avalon-ST pass-through interface, you must ensure your logic does not use a transaction ID assigned to another instantiated Logical layer module for transmitting request packets that expect an ftype=13 response packet. If you use such a transaction ID, the response routes away from the Avalon-ST pass-through interface and your custom module never receives the response.
Table 31.  Transaction ID Ranges and Assignments
Range Assignments
0-63 This range of Transaction IDs is used for ftype=8 responses by the Maintenance Logical layer Avalon-MM slave module.
64-127 ftype=13 responses in this range are reserved for exclusive use by the Input-Output Logical layer Avalon-MM slave module.
128-143 ftype=13 responses in this range are reserved for exclusive use by the Doorbell Logical layer module.
144-255 This range of Transaction IDs is currently unused and is available for use by Logical layer modules connected to the pass-through interface.
The RapidIO II IP core Transport layer routes response packets of ftype=13 with transaction IDs outside the 64–143 range to the Avalon-ST pass-through interface. Your system should not use transaction IDs in the 0-63 range if the Maintenance Logical layer Avalon-MM slave module is instantiated, because their use might cause the uniqueness of transaction ID rule to be violated.

If the Input-Output Avalon-MM slave module or the Doorbell Logical layer module is not instantiated, the RapidIO II IP core Transport layer routes the response packets in the corresponding Transaction IDs ranges for these layers to the Avalon-ST pass-through interface.

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