Embedded Design Handbook

ID 683689
Date 8/28/2023
Public
Document Table of Contents

3.4.1.1. Hardware Endianness

Hardware developers can map the data bits of an interface in any order. There must be coordination and agreement among developers so that the data bits of an interface correctly map to address offsets for any master or slave interface connected to the interconnect. Consistent hardware endianness or bus byte ordering is especially important in systems that contain IP interfaces of varying data widths because the interconnect performs the data width conversion between the master and slave interfaces. The key to simplifying bus byte ordering is to be consistent system-wide when connecting IP cores to the interconnect. For example, if all but one IP core in your system use little endian bus byte ordering, modify the interface of the one big endian IP core to conform to the rest of the system.

The way an IP core presents data to the interconnect is not dependent on the internal representation of the data within the core. IP cores can map the data interface to match the bus data byte ordering specification independent of the internal arithmetic byte ordering.