Decoder/analyser package aids automotive Ethernet testing

BroadR-Reach allows multiple in-vehicle systems to simultaneously access information over single unshielded twisted-pair cables. The technology delivers relatively high-speed data, 100 Mbps, with low connectivity costs and cabling weight.

The BroadR-Reach physical layer (BR-PHY) uses three-level pulse amplitude modulation (PAM3) signalling, limited to 33⅓ MHz bandwidth, and a data scrambling technique to equalize power spectral density within the allocated band.

It operates as a full-duplex connection with simultaneous Master-Slave/Slave-Master transmissions, so is more challenging to test than previous-generation networks such as CAN, CAN-FD and FlexRay.

Until now, most automotive Ethernet testing solutions required insertion of a hardware directional coupler to separate the bidirectional data streams.

But such couplers can interfere with normal functioning of the network and deliver misleading test results.

The PicoScope Software Directional Coupler utilises two non-intrusive differential voltage probing points a known distance apart, together with the known velocity of propagation in standard RG58 or Cat5 cable, to separate the transmitted data waveforms in each direction.

Once the waveforms have been separated to show up- and downstream traffic, the PicoScope BroadR-Reach decoder can be used to display the contents of each data packet, aligned with the transmitted waveform.

If required, two software directional couplers can be set up and decoded to show both the Master > Slave and Slave > Master communications at once. The decoded data can also be displayed in tabular listing format for ease of viewing.

Filtering and search tools are provided to help engineers focus on specific packet and field contents of interest.

Trevor Smith, Business Development Manager at Pico Technology, said “BroadR-Reach technology has been widely adopted for the next generation of automotive networks. The PicoScope decoder/analyzer enables engineers to solve the critical signal analysis and network verification challenges that they face when bringing those designs to market. It is included as standard with PicoScope 6.14.10 application software, and builds on our heritage of support for automotive protocols that includes CAN, CAN-FD, FlexRay, LIN and SENT.”

Smith added “We offered beta versions of the decoder/analyser to some key automotive customers during the summer, and received very positive responses and useful feedback. It helped us to validate the Software Directional Coupler algorithm and functionality of the decoder. Now the wider community of engineers working on automotive networks will benefit from that effort.”

Recommended hardware is the PicoScope 6000 – any model which offers bandwidth from 250 to 500MHz, 5GS/s sampling and capture memory up to 2 gigasamples.

Also recommended are the TA045 200 MHz differential probes (x2) for probing the two test points on the BroadR-Reach network.