How Ethernet AVB is playing a central role in automotive streaming applications

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Ethernet is emerging as the network of choice for infotainment and advanced driver assistance systems, Atmel’s Tim Grai explains.

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Imagine you’re driving down the highway with the music blaring, enjoying the open road. Now imagine that the sound from your rear speaker system is delayed by a split second from the front; your enjoyment of the fancy in-car infotainment system comes to a screeching halt.

Ethernet is emerging as the network of choice for infotainment and advanced driver assistance systems that include cameras, telematics, rear-seat entertainment systems and mobile phones. But standard Ethernet protocols can’t assure timely and continuous audio/video (A/V) content delivery for bandwidth intensive and latency sensitive applications without buffering, jitter, lags or other performance hits.

Audio-Video Bridging (AVB) over Ethernet is a collection of extensions to the IEEE802.1 specifications that enables local Ethernet networks to stream time synchronised, loss sensitive A/V data. Within an Ethernet network, the AVB extensions help differentiate AVB traffic from the non-AVB traffic that can also flow through the network. This is done using an industry standard approach that allows for plug-and-play communication between systems from multiple vendors.

The extensions that define the AVB standard achieve this by:

• reserving bandwidth for AVB data transfers to avoid packet loss due to network congestion from ‘talker’ to ‘listener(s)’
• establishing queuing and forwarding rules for AVB packets that keep packets from bunching and guarantee delivery of packets with a bounded latency from talker to listener(s) via intermediate switches, if needed
• synchronizing time to a global clock so the time bases of all network nodes are aligned precisely to a common network master clock, and
• creating time aware packets which include a ‘presentation time’ that specifies when A/V data inside a packet has to be played.

Designers of automotive A/V systems need to understand the AVB extensions and requirements, as well as how their chosen microcontroller will support that functionality.

AVB: A basket of standards

AVB requires that three extensions be met in order to comply with IEEE802.1:

• IEEE802.1AS – timing and synchronisation for time-sensitive applications (gPTP)
• IEEE802.1Qat – stream reservation protocol (SRP)
• IEEE802.1Qav – forwarding and queuing for time-sensitive streams (FQTSS).

In order to play music or video from one source, such as a car’s head unit, to multiple destinations, like backseat monitors, amplifiers and speakers, the system needs a common understanding of time in order to avoid lags or mismatch in sound or video. IEEE802.1AS-2011 specifies how to establish and maintain a single time reference – a synchronised ‘wall clock’ – for all nodes in a local network. The generalized precision time protocol (gPTP), based on IEEE1588, is used to synchronize and syntonize all network nodes to sub-microsecond accuracy. Nodes are synchronized if their clocks show the same time and are syntonised if their clocks increase at the same rate.

This protocol selects a Grand Master Clock from which the current time is propagated to all network end-stations. In addition, the protocol specifies how to correct for clock offset and clock drifts by measuring path delays and frequency offsets. New MCUs, such as the Atmel | SMART SAMV7x (shown above), detect and capture time stamps automatically when gPTP event messages cross MII layers. They can also transport gPTP messages over raw Ethernet, IPv4 or IPv6. This hardware recognition feature helps to calculate clock offset and link delay with greater accuracy and minimal software load.

Meanwhile, SRP guarantees end-to-end bandwidth reservation for all streams to ensure packets aren’t delayed or dropped at any switch due to network congestion, which can occur with standard Ethernet. For the in-vehicle environment, SRP is typically configured in advance by the car maker, who defines data streams and bandwidth allocations.

Talkers (the source of A/V data) ‘advertise’ data streams and their characteristics. Switches process these announcements from talker and listeners to:

• register and prune streams’ path through the network
• reserve bandwidth and prevent over subscription of available bandwidth
• establish forwarding rules for incoming packets
• establish the SRP domain, and
• merge multiple listener declarations for the same stream

The standard stipulates that AVB data can reserve only 75% of total available bandwidth, so for a 100Mbit/s link, the maximum AVB data is 75Mbit/s. The remaining bandwidth can be used for all other Ethernet protocols.

In automotive systems, the streams may be preconfigured and bandwidth can be reserved statically at system startup to reduce the time needed to bring the network into a fully operational state. This supports safety functions, such as driver alerts and the reversing camera, that must be displayed within seconds.

SRP uses other signalling protocols, such as Multiple MAC Registration Protocol, Multiple VLAN Registration Protocol and Multiple Stream Registration Protocol to establish bandwidth reservations for A/V streams dynamically.

The third extension is FQTSS, which guarantees that time sensitive A/V streams arrive at their listeners within a bounded latency. It also defines procedures for priority regenerations and credit based traffic shaper algorithms to meet stream reservations for all available devices.

The AVB standard can support up to eight traffic classes, which are used to determine quality of service. Typically, nodes support at least two traffic classes – Class A, the highest priority, and Class B. Microcontroller features help manage receive and transmit data with multiple priority queues to support AVB and ‘best effort class’ non AVB data.

Automotive tailored requirements

Automotive use cases typically fix many parameters at the system definition phase, which means that AVB implementation can be optimised and simplified to some extent.

• Best Master Clock algorithm (BMCA): the best clock master is fixed at the network definition phase so dynamic selection using BCMA isn’t needed.
• SRP: all streams, their contents and their characteristics are known at system definition and no new streams are dynamically created or destroyed; the proper reservation of data is known at the system definition phase; switches, talkers and listeners can have their configurations loaded at system startup from pre-configured tables, rather than from dynamic negotiations
• Latency; while this is not critical, delivery is. Automotive networks are very small with only a few nodes between a talker and listener. It is more important not to drop packets due to congestion.

Conclusion

The requirement to transfer high volumes of time sensitive audio and video content inside vehicles necessitates developers to understand and apply the Ethernet AVB extensions. AVB standardization results in interoperable end-devices from multiple vendors that can deliver audio and video streams to distributed equipment on the network with micro-second accuracy or better. While the standard brings complexities, new MCUs with advanced features are simplifying automotive A/V design.

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This article was originally published on New Electronics on October 13, 2015 and authored by Tim Grai, Atmel’s Director of Automotive MCU Application Engineering. 

Atmel’s new car MCU tips imminent SoC journey

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The fact that these MCUs are targeting highly-sophisticated connected car applications like infotainment and ADAS means that the journey toward bigger and more powerful chips is now inevitable.

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The automotive industry has reached a new era marked by giant initiatives like infotainment, connected car and semi-autonomous vehicles. And, no one seems more excited than the MCU guys who have been a part and parcel of in-car electronics for the past two decades. However, the humble microcontroller is going through a profound makeover in itself in order to come to terms with the demands of the connected car environment.

Take Atmel Corporation, one of the top MCU suppliers, who has launched its SAM DA1 family of microcontrollers at Embedded World 2015 in Nuremberg, Germany. The automotive-grade ARM Cortex-M0+-based MCUs come with capacitive touch hardware support for human-machine interface (HMI) and local interconnect network (LIN) applications. The SAM DA1 series integrates peripheral touch controller (PTC) for capacitive touch and eliminates the need for external components while minimizing CPU overhead. The feature is aimed at capacitive touch button, slider, wheel and proximity sensing applications.

Moreover, SAM DA1 microcontrollers offer up to 64KB of Flash, 8KB of SRAM and 2KB read-while-write Flash. The other key features of SAM DA1 series include 45 DMIPS and up to six serial communication interface (SERCOM), USB and I²S ports. SERCOM is configurable to operate as I²C, SPI or USART, which gives developers flexibility to mix serial interfaces and have greater freedom in PCB layout.

Atmel | SMART SAM DA1 ARM based Cortex-M0+ microcontrollers

The automotive-grade MCUs — operating at a maximum frequency of 48MHz and reaching a 2.14 Coremark/MHz — are qualified to the AEC Q-100 Grade 2 (-40 to +105degreeC). According to Matthias Kaestner, VP of Automotive at Atmel, the company is targeting the SAM DA1 chips for in-vehicle networking, infotainment connectivity and body electronics.

Automotive touch surface demo at Embedded World 2015

The fact that the SAM DA1 devices are based on powerful ARM cores clearly shows a trend toward more performance and the ability to run more tasks on the same MCU. The Cortex-M0+ processor design comes with a two-stage pipeline that improves the performance while maintaining maximum frequency. Moreover, it supports a new I/O interface that allows single cycle accesses and enables faster I/O port operations.

That’s no surprise because the number of electronic control units (ECUs) is on the rise amid growing momentum for connected car features like advanced driver assistance systems (ADAS). However, a higher number of ECUs will make the communication among them more intense; so automotive OEMs want to reduce the number of ECUs while they want more value from the MCU.

Moreover, car vendors want to bring down the number of ECUs to avoid complexity within the larger car network. The outcome of this urge is the integration of more performance and functionality onto the MCU. Each ECU has at least one microcontroller.

Atmel and the Evolution of MCU

Atmel’s SAM DA1 device is another testament that the boundaries between MCU and SoC platforms are blurring. The fact that these MCUs are targeting highly sophisticated connected car applications like infotainment and ADAS means that the journey toward bigger and more powerful chips is now inevitable.

Atmel is an MCU company, and this product line has played a crucial role in its transformation that started in the late 2000s. At the same time, however, the San Jose, California–based chipmaker seems fully aware of the critical importance of the system-level solutions. Atmel calls the SAM DA1 family of chips MCUs; however, its support for more peripherals, larger memories and intelligent CPU features show just how much the MCU has changed over the course of a decade.

Memory Protection Unit in Cortex-M0+

Atmel has a major presence in the automotive market with its MCUs and touch controllers being part of the top-ten car vendors. It’s interesting to note that, beyond its MCU roots, Atmel has a lot of history in automotive electronics as well. Atmel was one of the first chipmakers to enter the automotive market.

Moreover, Atmel bought the IC division of Temic Telefunken Microelectronic GmbH for approximately $110 million back in 1998. Telefunken was an automotive electronics pioneer with an early success in electronic ignition chips that made way into Volkswagen cars back in 1980.

The release of SAM DA1 series marks a remarkable opportunity as well as a crafty challenge for Atmel in the twilight worlds of MCU and automotive electronics. Tom Hackenberg, a senior analyst at IHS, calls the phenomenon ‘SoC on wheels.’

Hackenberg says that the automotive industry consumed approximately a third of all MCUs shipped in 2013. However, now there is an SoC on the road, the brain behind the connected car, and it commands a deeper understanding of the AEC-Q100 standard for automotive quality and ISO 26262 certification for car’s functional safety.

Atmel’s AvantCar touchscreen demo at the CES 2015

The integration of touch controller into SAM DA1 chips can be an important value proposition for the car OEMs who are burning midnight oil to develop cool infotainment platforms for their newer models. Next, while AEC Q100 Grade 2 qualification is a prominent part of the SAM DA1, Atmel might have to consider augmenting the ISO 26262 certification for functional safety, a vital requirement in ADAS and other connected car features.

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Majeed Ahmad is author of books Smartphone: Mobile Revolution at the Crossroads of Communications, Computing and Consumer Electronics and The Next Web of 50 Billion Devices: Mobile Internet’s Past, Present and Future.

 

Report: 1 in 5 cars will be connected by 2020

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The increased consumption and creation of digital content within cars will lead to sophisticated information and entertainment systems.

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If you buy a car within the next five years, it’s likely that it will be Internet-enabled. That’s the prediction Gartner has shared, anyway. The market research firm has released its latest report that expects there to be approximately 250 million connected cars on the road by 2020, paving the way for new in-vehicle services and automated driving capabilities. In other words, one in five vehicle will boast some sort of wireless network connection.

During the next five years, the proportion of new vehicles equipped with this capability will increase dramatically, making connected cars an integral element of the rapidly-growing Internet of Things (IoT) — an area Gartner forecasts will entail 4.9 billion connected things in use this year and will reach 25 billion by 2020.

“The connected car is already a reality, and in-vehicle wireless connectivity is rapidly expanding from luxury models and premium brands, to high-volume midmarket models,” explained James F. Hines, Gartner Research Director. “The increased consumption and creation of digital content within the vehicle will drive the need for more sophisticated infotainment systems, creating opportunities for application processors, graphics accelerators, displays and human-machine interface technologies. At the same time, new concepts of mobility and vehicle usage will lead to new business models and expansion of alternatives to car ownership, especially in urban environments.”

The proliferation of vehicle connectivity will have implications across the major functional areas of telematics, automated driving, infotainment and mobility services. Driving the adoption of connected car technology is the expansion of high-bandwidth wireless network infrastructure, rising expectations for access to mobile content and better service from smartphones and tablets. While many of the major automakers have rolled out connected cars in a number of limited models, in-vehicle wireless connectivity is rapidly expanding from luxury and premium brands to high-volume mid-market versions. Take for instance, General Motors, Hyundai and Chrysler, who have each partnered with telecoms AT&T, Verizon and Sprint, respectively.

By 2018, two automakers will have announced plans to become technology companies and expand their connected-vehicle value experiences to other industries and devices, Gartner said in a report last year. And over the next five years, at least one auto company will achieve 10% of its total revenues from connected mobility and service offerings.

“The increased consumption and creation of digital content within the vehicle will drive the need for more sophisticated infotainment systems, creating opportunities for application processors, graphics accelerators, displays and human-machine interface technologies,” Hines stated.

As the amount of information being fed into in-car head unit or telematics systems grows, vehicles will be able to capture and share not only internal systems status and location data, but also changes in surroundings in real-time, Computer World writes. Ultimately, your car will become just another part of your mobile data plan.

“To facilitate that kind of shift, connected-vehicle leaders in automotive organizations need to partner with existing ecosystems like Android Auto or Apple CarPlay that can simplify access to and integration of general mobile applications into the vehicle,” Gartner Analyst Thilo Koslowski shared in last year’s report.

The Gartner report follows recent revelations from IBM, who in the company’s Automotive 2025 study found that a majority of executives believe cars will become more personalized for drivers over the next 10 years, but autonomous vehicles and self-driving cars will not yet be ubiquitous. In fact, IBM anticipates that by 2025, vehicles will be intelligent enough to configure themselves to a driver and other occupants. In other words, cars will be able to learn, heal, drive and socialize with others on the road, and their surrounding environment through vehicle-to-vehicle communication.

Without question, the demand for advanced driver assistance systems (ADAS) is on the rise as well. According to ABI Research analysts, the market is expected to grow from $11.1 billion last year to $91.9 billion by 2020, hitting the $200 billion mark by 2024. Fueling that growth is the expansion of the technology from high-end luxury vehicles to more affordable cars and mini automobiles. One of the most popular systems on high-end vehicles, adaptive cruise control (ACC), will continue to gain popularity across all vehicle segments, with shipments experiencing a CAGR of 69% between 2014 and 2020.

 

Ford’s new SYNC will be more like your smartphone

Ford has shared that its in-car infotainment system will be getting an overhaul with the newly-revealed SYNC 3, which will add a capacitive touchscreen, an improved smartphone-like interface, enhanced mobile app integration, and support for Android Auto and Apple CarPlay in the near future.

First debuting back in 2007, SYNC is Ford’s voice-based car entertainment system that enables drivers to play certain media, connect their mobile devices and audio players, and change the temperature, radio station or make calls via verbal commands. Over the next two years, the carmaker introduced a pair of updated versions, which ushered in new applications including 911 Assist, Vehicle Health Report, as well as traffic, directions and information.

By far, the largest hardware change will be the system’s migration from resistive to capacitive touchscreens. According to Ford, SYNC 3 will feature optimized capacitive screens that offer an experience most consumers are familiar with from their tablets and smartphones. With a quicker response to touch, voice and phone-like gestures, future vehicles will boast multi-touch, pinch-to-zoom and swipe capabilities with modernized graphics.

“We considered all the modern smartphones and mobile operating systems and created something familiar but unique,” explained Parrish Hanna, Ford Global Director of HMI.

In doing so, SYNC 3 aims to reduce on-screen complexity and prioritize the control options drivers utilize most. As the carmaker notes, a bright background and large buttons with high-contrast fonts for daytime use will help reduce screen washout in the sun. Meanwhile, at night, the display will automatically switch to a dark background to aid in eye fatigue reduction and minimal reflections on the windows.

Phone contacts will be searchable via a simple swipe of the finger to scroll through the alphabet. With “One Box Search,” SYNC 3 users can look up points of interest or enter addresses in much the same way they use an Internet search engine.

“Simplicity has value,” added Hanna. “Reducing the number of things on-screen also makes control easier and is designed to limit the number of times a driver has to glance at the screen.”

In addition, an updated AppLink functionality will provide drivers with better control of their smartphone applications from the car’s main display. It automatically recognizes compatible apps on a user’s smartphone, and enables them to be controlled by voice and steering wheel buttons. Take Google Now, Apple Siri and Pandora, for example, which will be available to those who access the system in the car through Bluetooth.

“Overall, AppLink is faster, more responsive and easier to find your apps,” revealed Julius Marchwicki, Ford Global Product Manager, AppLink. “The overall design of SYNC 3 allows for better integration with smartphones – resulting in a more user-friendly experience.”

The Sync software will also have the ability to be updated via a home Wi-Fi network, assuming that the home’s network is in range.

According to Ford, the SYNC 3 is expected to be launched in new vehicles next year. Interested in learning more? You can find the entire press release here.

Speaking of in-vehicle systems, Atmel’s maXTouch family — known for its superior performance and rich feature set — is now qualified for automotive applications, ranging from touchscreens and touchpads (supporting 2 inches up to 14 inches in diameter) used in center stack displays to navigation systems and radio human-machine interfaces (HMIs). Looking ahead, here’s a sneak peek at what the future holds for center consoles.

Introducing Atmel’s new LIN family for in-vehicle networking

LIN (Local Interconnect Network) is a serial network protocol used for communication between various automobile components to enable comfort, power-train, infotainment sensor, and actuator applications. The LIN Consortium was founded by five automakers (BMW, Volkswagen Audi Group, Volvo Cars, DaimlerChrysler) in the late 1990s, with the first fully-implemented version of the new LIN specification (1.3) published in November 2002. Version 2.0 was later introduced in September 2003, offering expanded capabilities and support for additional diagnostics features.

Fast forward 11 years later, Atmel is excited to announce its next-generation family of LIN transceivers, system basis chips (SBC) and voltage regulators for a wide-range of vehicle applications. The new family is the industry’s first to comply with the new original equipment manufacturer (OEM) hardware recommendations and provide scalable functionality to improve the overall system cost.

“As the leading provider of automotive LIN ICs, Atmel is committed to bringing more innovative LIN products to the market,” said Claus Mochel, Atmel Marketing Director for Automotive High Voltage Products.

All the new devices in this new family feature an LDO with outstanding minimum supply voltage of 2.3V combined with linear mode current of 130uA to support data storage even during an unexpected shut down. This new family is compliant with the latest standards including LIN 2.0, 2.1, 2.2, 2.2A and SAEJ2602-2. Some members of the family also include application specific functions such as relay drivers, watchdog, high-side switches and wake up inputs to enable system designers to build innovative in-vehicle network applications in next-generation automobiles.

The devices are available in DFN packages with heat-slug and wet-able flanks to support optical solder inspection. These next-generation devices also provide a family package footprint so that designers can upgrade their designs with various devices within the LIN SBC family.

“Our expanded LIN portfolio includes pin-outs that are the first to support the new OEM hardware recommendations enabling system designers to develop differentiated LIN systems in next-generation vehicles. Atmel’s LIN family footprint makes it easier to migrate upwards and devices in the family offer application-specific functionality for various LIN-connected applications such as window lifters, sun-roofs, trunk opener or seat controls,” Mochel added.

Key features of the ATA6632/33/34 include:

• +3.3V/5V/85mA LDO suitable for usage with low-cost multi layer ceramic capacitors
• 2.3V lowest operating voltage
• Very low current consumption in linear mode
• Sleep current; Normal mode current
• DFN 8 (3x3mm) and DFN16 (3*5.5mm), wet-able flanks included, allowing automatic optical inspection of the solder joint

In order to accelerate the design development, an evaluation kit is also available to support the new LIN devices. The ATAB663xxxA development kit allows designers to quickly start designing with Atmel’s LIN family. The kit is easy-to-use with a pre-defined set-up. All pins are easily accessible for quick testing. The kits allow designers to select master or slave operation with a mounting option for LIN pull-up resistor and series diode.

Those interested will be happy to learn that samples for all family members are now available. You can find more detailed information — including datasheets and request forms — here.

Heading to Munich next week for Electronica 2014? Cruise on over to the Atmel booth — located in Hall A5, #542 — to discover how we’re bringing the IoT to the connected car though simple, touch-enabled human machine interfaces. There, you will find a number of automotive demos, including a door handle powered by Atmel’s fourth generation LIN device that features a curved touch-enabled glass display, providing excellent multi-touch performance for future automotive applications, and utilizing Atmel’s XSense and the maXTouch 2952T.