Analog Devices EE-39 Interfacing Byte Programmed Flash Memories to the ADSP-218x

About this manual

This Engineering Note (EE-39) describes how to interface 5V Flash memories to the ADSP-218x Digital Signal Processor. It details the wiring connections between the DSP and Flash devices via the BDMA port and explains the byte-by-byte programming protocol used by AMD Flash memories. The document covers operations such as autoselect, byte write, sector erase, and chip erase.

What's inside

• Introduction
• BDMA Wiring
• Basic AMD FLASH Operation
• Flash Programming via the BDMA Port
• BDMA Wait State Generation
• Flash Server Software
• FLASH System Caveats
• Byte Programming

Specifications

Frequently asked questions

What is the purpose of the WR signal in Flash systems?

The WR signal is the only additional signal necessary for Flash systems when changing the contents of the Flash.

How can the BDMA Write Anomaly on some ADSP-218x revisions be countered?

It can be countered with a simple RC network attached to each data pin and to ground (R=120 Ω, C=47pF).

What is the only operation that converts a logic '0' to a logic '1' in Flash programming?

A sector or chip erase operation is the only operation that converts a logic '0' to a logic '1'.