I2C Bus Monitor FAQ (Frequently Asked Questions)

Which I2C Bus Monitor do I need?

We currently offer two I2C Bus monitor/analyzers. Both instruments connect directly to an I2C, SMBus, or other derived bus, and captures, filters, and displays bus activity. The two instruments differ in capabilities, hardware, features, and host computer interfaces. This FAQ will help you decide which monitor/analyzer is right for you.

The I2C Bus Monitor Plus (#MIIC-102, Data Sheet, User's Guide) is our most powerful and configurable laboratory grade troubleshooting instrument for the Inter-Integrated Circuit (I2C) Bus, SMBus, and other derived protocols. When connected to an I2C or derived protocol bus, the I2C Bus Monitor Plus captures, filters, and displays bus message data and timing information.

I2C Bus Monitor Plus features include:

1. Data capture at up to 400K bps (Fast Mode).
2. Filtering of displayed messages by slave address and message data.
3. Timestamping of each bit, byte, and message with microsecond accuracy.
4. Software selectable I2C Bus signal logic level voltage thresholds (down to 1.8V).
5. High speed host computer interface options (ISA, PCI, or PC Card).
6. Extensive software for message filtering, analysis, logging, and display.
7. Displays SMBus Smart Battery System data in engineering units.

This I2C Bus Monitor Plus uses dedicated hardware technology to collect and deliver bus data to a host PC for logging, analysis, and display. It cannot clock stretch, and is non-intrusive on bus operation.

Recommendation: We recommend the I2C Bus Monitor Plus for traffic intensive I2C Bus, SMBus, or derived protocol applications, 400K bps (Fast Mode) applications, low voltage applications, and applications requiring timing analysis or extensive content filtering.

The I2C Bus Monitor (#MIIC-101, Data Sheet, User's Guide) is our most cost effective troubleshooting instrument for I2C, SMBus, and other derived protocols. Operating either hand-held or remotely via an RS-232 serial communication link to a PC, this unit can:

1. Collect bus traffic at up to 100K* bits per second (bps).
2. Filter message data by slave address.
3. Work with bus signal levels down to 3.3 volts.
4. Display bus data on its built-in LCD display.

With the aid of our optional Windows based I2C/SMBus Analysis Software, the I2C Bus Monitor can:

5. Display bus message data on the screen of a host PC.
6. Log captured bus data to a file.
7. Display SMBus Smart Battery System data in engineering units.

*The I2C Bus Monitor uses microprocessor/firmware technology to collect bus data. This technology makes use of I2C Bus clock stretching (holding the SCL line low) during data collection. Clock stretching can slow the bus for up to twelve (12) microseconds during a byte transfer. Since not all bus master devices support clock stretching (wait for the clock stretch to complete), connection of the Bus Monitor to such an "out of specification" systems may cause the system to fail.

Recommendation: We recommend the I2C Bus Monitor for low to middle intensity I2C Bus, SMBus, or derived protocol applications, 100K bps (Standard Mode) applications, 3.3 to 5 volt applications, applications with elevated ground planes, and applications requiring hand-held instrumentation.

I2C is just a mouse click away ^TM

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Page up-dated at June 04, 2007