Analog Devices EE-220 Using External Memory with ADSP-2126x SHARC DSPs

About this manual

This Engineer-to-Engineer Note (EE-220) describes the changes in external memory addressing functionality for the third generation SHARC family of processors, specifically those using the Parallel Port. Unlike previous SHARC DSPs that used an External Port with built-in address translation, the Parallel Port requires physical word addresses and lacks automatic translation, necessitating special software considerations.

What's inside

• Introduction
• External Memory Addressing
• Organizing Data using LDF
• 48-bit Address Translation
• Operation of Parallel Port DMA Count Registers
• Using the Emulator to View External Memory

Specifications

Frequently asked questions

What is the main difference between the Parallel Port and the previous External Port?

The Parallel Port no longer accepts logical addresses from the core and requires the physical word address to be supplied to the DMA engine.

Is address translation built-in for the Parallel Port?

No, the Parallel Port does not have the address translation built-in and operates on physical addresses only.

Which VisualDSP++ command is required for external memory initialization?

The LDF must include the PACKING() command to enable the linker to generate addresses the Parallel Port can use.