Analog Devices Serial Port Development and Troubleshooting Guide

About this manual

This document serves as an Engineer-to-Engineer note designed to assist engineers in designing and debugging serial port communications within systems utilizing Analog Devices DSPs. It addresses general system design strategies to ensure low noise levels and valid signals, focusing on hardware construction and decoupling techniques.

What's inside

• General ADSP-21xx / 2106x DSP SPORT Design Issues
• Decoupling the DSP's Vcc and GND Pins
• Hardware Construction (PCB vs. Wirewrap)
• Signal Trace Length
• DSP is Receiving and/or Transmitting Corrupt Data
• Shifted Data
• Incorrect Bits
• No activity on serial port lines
• Invalid line levels on serial port lines
• Noise on serial port lines

Specifications

Frequently asked questions

What causes shifted data in serial communication?

Shifted data usually indicates a data synchronization problem, often caused by a noisy serial clock or system noise when transmitting unframed data.

What causes incorrect bits in received serial data?

Incorrect bits in received serial data are usually caused by a system noise problem.

When should serial port traces be treated as transmission lines?

Serial lines greater than about 3 inches require reflection compensation and must be treated as transmission lines.