With each new emerging technology, the need for a reliable and robust, yet simple and interoperable communication infrastructure rises exponentially. Depending on the scope, various solutions take a different approach to this problem. Some older technologies are sometimes reused in a completely new way, offering their inherent simplicity, enhanced by some new and innovative features that are possible today. One such technology is Single Pair Ethernet (SPE). SPE relies on the simplicity of one of the first physical implementations of the Ethernet standard, using only a single twisted pair of wires as a data transport medium, while providing many advantages over more common T/TX implementations, especially in industrial and automotive applications.
OPEN Alliance BroadR-Reach and IEEE Standardization
Broadcom was one of the first companies to utilize SPE and its advantages, developing BroadR-Reach – its own proprietary technology, based around SPE. This technology was primarily designed for automotive applications, allowing full-duplex Ethernet network over unshielded twisted pair (UTP). As a result, in-vehicle cabling weight, complexity, and overall connectivity costs were reduced significantly. The success of the BroadR-Reach technology was recognized by several big names in the automotive and semiconductor industries, including BMW, Freescale, Harman, Hyundai, NXP, and STMicroelectronics. Together with Broadcom, they formed OPEN Alliance, a Special Interest Group (SIG) focused on establishing BroadR-Reach as an open standard and promoting its use in automotive networking applications. Today, OPEN Alliance SIG counts more than 140 members.
SPE in the form of the IEEE’s 100BASE-T1 standard (also known as IEEE 802.3bw) differs very little from the OEPN Alliance BroadR-Reach standard. Well-proven in the automotive industry, this standard lays the foundations for its use in other areas, including industrial automation and IIoT. As a result, more alliances were formed around this standard, bringing together leading technology companies from different industries and fields of application, all with the common goal: promoting the use of IEEE standardized SPE technology for industrial and IIoT applications.
Auto-Link-SPE-G Media Converter by i-Novative
However, to enable full interoperability between the T/TX and T1 networks, and overcome their physical differences, a special media conversion device is required. One such device is the Auto-Link-SPE-G Media Converter, developed by i-Novative, a partner company specialized in automotive networking and the design of customer-specific network solutions. Auto-Link-SPE-G Media Converter is based around Broadcom BCM89881 (T1 side) and BCM54811 (T/TX side) PHY ICs, supporting 100/1000 Mbps link speeds. It features IEEE 802.3bp auto-negotiation and proprietary master/slave detection functionality, even if the T1 partner does not support the IEEE 802.3bp auto-negotiation protocol (easily configurable via a DIP switch). The primary purpose of the Auto-Link-SPE-G Media Converter is to allow automotive and industrial T1-based network development and testing. As such, it provides link quality monitoring, cable diagnostics, and quick access to all configuration registers of both PHYs via the included software, enabling full control over the link parameters.
Broadcom’s BCM54811 triple-speed 10/100/1000BASE-T transceiver IC performs all the physical functions for the BASE-T/TX interface, providing connectivity over the standard RJ45 connector. This advanced PHY features Broadcom’s field-proven signal processing technology and accompanying circuitry, offering exceptional noise cancellation and very low jitter that exceeds IEEE specifications. The BCM54811 is designed for reliable operation over extended cable length, even when used with the worst-case scenario CAT5 cable plants, featuring auto-negotiation functionality to determine the optimal link speed with its partner (Ethernet@WireSpeed™). It also features an extensive cable diagnostics subsystem (CableChecker™), providing detection of the most common cable problems (cable shorted, cable break, cable length). Some of its key features include compliance with the IEEE 802.3az standard and support for Energy Efficient Ethernet (EEE). Finally, this PHY also supports BroadR-Reach with auto-negotiation up to 100 Mbps. However, i-Novative selected another, more specialized PHY for the T1 interface, allowing seamless media conversion for data rates up to 1000 Mbps on both sides.
The BCM89881 is a monolithic 100/1000BASE-T1 Ethernet transceiver that performs all the physical functions for the T1 side of the Auto-Link-SPE-G Media Converter, providing connectivity over a Mini50 four-pin connector. This device is a highly integrated 100/1000BASE-T1 PHY that also features Broadcom’s field-proven signal processing technology, thus enabling superior EMC and EMI performance, fast link-up time, low power consumption, and robust signal integrity over shielded and unshielded twisted pair cables. It is AECQ-100 qualified, ensuring compliance with the stringent automotive requirements for high EMI/EMC noise immunity and transmission jitter. Among many other features, the BCM89881 also supports BroadR-Secure™ functionality for packet authentication and enhanced security. Extensive cable management functions allow the detection of the most common cable problems, while the Signal Quality Indicator (SQI) reports the status of the signal quality in eight discrete steps.
Both PHYs offer the industry’s lowest power consumption, compliance with the IEEE 1588/IEEE 802.1AS timing standards, and exceptional signal ruggedness required for both automotive and industrial applications. Therefore, using these particular PHYs was a logical choice for the Auto-Link-SPE-G Media Converter, making it an extremely capable device not only for reliable 100/1000 Mbps media conversion, but also for extensive network diagnostics. Network developers can use the included software to monitor the signal quality, perform cable diagnostics, and even track cable faults with a precision of ±1.5 m from the device. As already mentioned, all the registers of both PHYs are accessible over the included software, which is very useful for network development. Although BCM54811 does not comply with Clause 45 specifications, i-Novative still made it possible to write to all of its registers. For more information and a full list of features, please visit the i-Novative official web page, and make sure to check their promo material in the downloads section (both German and English versions are included).
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