RapidIO Intel FPGA IP User Guide

ID 683884
Date 9/15/2021
Public
Document Table of Contents

4.4.2. Transaction ID Ranges

To limit the required storage, a single pool of transaction IDs is shared between all destination IDs, although the RapidIO specification allows for independent pools for each Source-Destination pair. Further simplifying the routing of incoming ftype=13 response packets to the appropriate Logical layer module, the Input-Output Avalon® -MM slave module and the Doorbell Logical layer module are each assigned an exclusive range of transaction IDs that no other Logical layer module can use for transmitted request packets that expect an ftype=13 response packet.

Table 18.  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.

Response packets of ftype=13 with transaction IDs outside the 64–143 range are routed to the Avalon® -ST pass-through interface. Transaction IDs in the 0-63 range should not be used 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, response packets in the corresponding Transaction IDs ranges for these layers are routed to the Avalon® -ST pass-through interface.