Normally we confine this blog to SPI/I2C/USB and CAN questions, but once in a while we're asked questions about other protocols.  This week, one customer wanted to know about MDIO.

Q:  Do any of your products support MDIO? Host Adapter? Analyzer?

The Beagle I2C/SPI Protocol Analyzer non-intrusively monitors I2C, SPI and MDIO data in real time.

A:  The Beagle I2C/SPI Protocol Analyzer non-intrusively monitors MDIO up to 2.5 MHz. The Beagle I2C/SPI analyzer monitors clause 22 and clause 45 MDIO using v2.20 of Data Center software or any version of the Beagle Software API. The Beagle MDIO signal, pin 8, is the management data input/output, and it is bidirectional signal, which is used to transfer data between the STA and the MMD. The Beagle MDC signal, pin 7, is the management data clock, which is a control line that is driven by the STA and synchronizes the flow of the data on the MDIO line.  The Beagle analyzer signals level is 3.3V. To monitor a lower voltage MDIO bus, you could use our level shifter board.

In order to properly capture MDIO signals, the sampling rate must be set properly. For MDIO monitoring, the minimum requirement for the sampling rate is twice the bus bit rate. In order to farther assist you, can you provide me the customer system requirements, application, and block diagram? For additional information take a look at the Beagle analyzer datasheet sections 1.4, 2.4 and 6.9, Data Center manual section 1.24, and knowledge base article 10056. Let me know, if you have additional questions.

Beagle Protocol Analyzer Datasheet Section2.4

Data Center Software Manual Section 1.24

Monitoring MDIO with the Beagle I2C/SPI protocol analyzer

Do you have a question about other protocols or suggestions for new protocols - let us know here.