Intel® Agilex™ Hard Processor System Technical Reference Manual

ID 683567
Date 11/11/2022
Public

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7.7. Data Width Sizing

The HPS-to-FPGA bridge allows 32, 64, and 128-bit interfaces to be exposed to the FPGA fabric. For 32-bit and 128-bit interfaces, the bridge performs data width conversion to the fixed 64-bit interface within the HPS. This conversion is called upsizing in the case of data being converted from a 64-bit interface to a 128-bit interface. It is called downsizing in the case of data being converted from a 64-bit interface to a 32-bit interface. If an exclusive access is split into multiple transactions, the transactions lose their exclusive access information.

During the upsizing or downsizing process, transactions can also be resized using a data merging technique. For example, in the case of a 32-bit to 64-bit upsizing, if the size of each beat entering the bridge’s 32-bit interface is only two bytes, the bridge can merge up to four beats to form a single 64-bit beat. Similarly, in the case of a 128-bit to 64-bit downsizing, if the size of each beat entering the bridge’s 128-bit interface is only four bytes, the bridge can merge two beats to form a single 64-bit beat.