pnx1700 NXP Semiconductors, pnx1700 Datasheet - Page 805

• Manufacturer Part Number: pnx1700
• Description: Connected Media Processor
• Manufacturer: NXP Semiconductors

1. Introduction
1.1 Features
Two addressing conventions exist in the computer industry: little-endian and
big-endian.
The PNX17xx Series supports both big-endian mode and little-endian mode, allowing
it to run either little-endian or big-endian software, as required by the particular
application.
This chapter explains the concepts and programmer’s view of data structures
required for module control and module DMA. The chapter also contains a section
that shows how hardware modules, buses and bridges implement the programmer’s
view.
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Chapter 29: Endian Mode
PNX17xx Series Data Book – Volume 1 of 1
Rev. 1 — 17 March 2006
In the little-endian convention, a multi-byte number is stored in memory with the
least significant byte at the lowest memory address, and subsequent bytes at
increasing addresses.
In the big-endian convention, the most significant byte is stored at the lowest
memory address, and subsequent bytes are stored at increasing addresses.
The PNX17xx Series supports big-endian and little-endian operation.
The system as a whole (all CPUs and all on-chip DMA modules) must operate in
the same endian mode.
When used with an external CPU, the PNX17xx Series must operate in the same
endian mode as the external CPU. If the endian modes between the external
CPU and the PNX17xx Series are different, then the external CPU must be
aware of this difference and appropriately handle all data swapping.
The endian-mode choice is made at boot time. It can be changed by software, but
this requires a partial system reset.
Preliminary data sheet