Protocol analyzers

A protocol analyzer is a measuring instrument that analyzes one or more signals that are used to communicate between electronic devices according a specific protocol. A protocol analyzer examines the signals and decodes the information that is transferred. De decoded information can be displayed in graphs, meter sinks and table sinks.

A protocol analyzer is a useful tool when developing a hardware and/or software implementation of a communication bus. It can also be used when debugging device or bus failures.

The Multi Channel oscilloscope software contains the following protocol analyzers:

CAN analyzer

The CAN analyzer in the Multi Channel oscilloscope software can be used to decode messages which are transmitted on a CAN bus. The source for the CAN analyzer can either be the differential CAN signal or the CAN-high signal. All CAN bus bitrates are supported. Various fields from the CAN bus messages are decoded and can be displayed in a table as shown below.

Measurement on a CAN bus in a car, with data decoded by a CAN analyzer.Figure 1: Measurement on a CAN bus in a car, with data decoded by a CAN analyzer.

J1939 decoder

The J1939 decoder in the Multi Channel oscilloscope software extracts SAE J1939 SPN values from CAN messages. It has one input to receive CAN messages, from e.g. a CAN analyzer and can have multiple outputs. Each output contains the values of a single SPN (Suspect Parameter Number), selected from a database or loaded from a custom INI file. The data from these outputs can be used in graphs, meters, tables and by other I/Os.

J1939 decoder showing decoded engine coolant and manifold temperatures.Figure 2: J1939 decoder showing decoded engine coolant and manifold temperatures.

I²C analyzer

The I²C analyzer in the Multi Channel oscilloscope software analyzes both I²C signals and displays the transferred messages. Besides I²C busses, it also supports related buses like SMBus, ACCESS.bus and TWI.

I²C analyzer displaying multiple decoded eeprom read and write operations.Figure 3: I²C analyzer displaying multiple decoded eeprom read and write operations.

The I²C analyzer uses the SDA and SCL signals from the I²C bus and translates these into a chronological list of all instructions including their data. The I²C analyzer has the following features:

  • 10 kbps, 100 kbps, 400 kbps, 1 Mbps and 3.4 Mbps support
  • Missing ACK detection
  • 7 and 10 bits addressing support
  • Repeated start support
  • Clock stretching support
  • User defined alias per address for quick device recognition.

Serial analyzer

The Serial analyzer in the Multi Channel oscilloscope software analyzes one or more serial signals and displays the transferred messages. It supports RS232 serial interfaces, as well as related interfaces like RS485, MIDI, DMX and other compatible buses.

Serial analyzer displaying decoded serial data 'TiePie' transmitted in two directions.Figure 4: Serial analyzer displaying decoded serial data 'TiePie' transmitted in two directions.

The serial analyzer can simultaneously analyze and decode multiple communication signals. It features:

  • Automatic baudrate detection and user defined baudrate setting
  • Databits setting: 5, 6, 7 or 8
  • Parity setting: none, even, odd, mark or space
  • Stopbits setting: 1 or 2.