Tag Archives: Local Interconnect Network

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.


Designing next-gen LIN systems with Atmel (Part 3)

In the first part of this series, Bits & Pieces took a closer look at LIN, or Local Interconnect Network for vehicles. In part two, we discussed Atmel’s next-generation ATA6641/42 System Basis Chip (SBC) with an eight-channel high-voltage switch interface, a LIN2.1 and SAEJ2602-2-compliant LIN transceiver and lowdrop voltage regulator. We also talked about the SBC’s switch interface unit, or more specifically, switch inputs, switch monitoring (detection) and interrupt requests. In part three, we’re going to get up close and personal with voltage measurement, PWM control, H-Bridge relays and LIN auto-addressing.

In terms of voltage measurement, the I/O ports not only contain a high-voltage (HV) comparator for simple switches but also a voltage divider.


The low-voltage signal—which is linearly dependent on the input voltage—is provided at the VDIV pin to enable analog voltage measurements on the high-voltage pins by using the ADC of the application’s microcontroller. In addition, the VDIV pin—which can be sourced either by the VBATT pin or one of the switch input pins CS1 to CS8—guarantees a voltage and temperature-stable output ratio of the selected input.

On the subject of PWM control, the ATA6641/42’s switch interface current sources can be used to directly control pulse-width-modulated loads (such as LEDs). The PWM signal applied to the CSPWM input pin is used as control signal for the chosen current sources at the corresponding I/O ports.


This PWM signal can be applied to each I/O pin, as the CSPWM input pin accepts logic-level signals (such as those from the microcontroller) and is equipped with a pulldown structure so that, in case of an open connection, this input is well defined.

Up next is H-bridge Relay Control, as the ATA6641/42 can easily be used as a relay driver. If the 20mA output current of each I/O-port is not sufficient to drive the load, it is possible to connect the output pins together to achieve a higher load current. In the example shown in figure 8 three outputs are tied together.


This results in a minimum output current of 3 x 20mA = 60mA. As an additional safety feature, the CS1 and CS2 high-voltage interface pins are used as sensor inputs for checking proper relay operation. The relays are configured as H-bridges, allowing a motor to be driven in both directions. A typical application for this configuration is a window lifter.

Last up is LIN Auto-addressing. After switching on the network, and before the communication begins, each LIN slave node will be assigned a unique address.


Typically this address is implemented by hardwiring, programming (OTP or bitwise), special connectors, or DIP switches. Common to all the methods mentioned is the configuration of the system or the replacement of a faulty slave node requires manual action. The only way to avoid the latter is to store the slave nodes using different addresses.

In contrast to these methods, auto-addressing means that completely identical slave nodes can be connected to the LIN network without having to distinguish their addresses. The addresses of the individual nodes are assigned according to their position on the bus. Another solution is an automatic addressing process called slave node position detection. In this case, the master assigns the node addresses of the slaves during initialization. As all LIN nodes are in a wired AND connection, all bus connections are equal and thus not able to detect their position on the bus on their own. Additional measures are required to detect the relative position of every slave on the bus.

There are a number of methods that can be leveraged to achieve this, although an Atmel engineering rep told Bits & Pieces the ATA6641/42 is perfectly suited for an extra wire daisy chain scenarios because the two high-voltage I/O ports can be used as a high-side and low-side switch (figure 9 above shows the basic functionality of this method using the ATA6641/42).

“This method allows absolutely identical LIN slaves to be connected to the LIN bus without end-of-line or connector pin programming. All LIN slaves need to provide two extra pins; in the case of the ATA6641/42 these are the high voltage I/O CS1 and CS2 ports. Both are able to switch to VS or to GND,” the Atmel engineering rep explained. “The CS1 pin is the data input, and the CS2 pin is the data output. The CS1 data input of the first slave node is connected to the data output of the master. The output of the first node CS2 is connected to the input CS1 of the second node and so on, resulting in a daisy chain.”

The addressing procedure starts with all outputs (CS2) set to high level with the exception of the master. This means that the first slave node following the master node is detected by a low level at its data input. The first node selected in this way takes the address from the LIN configuration message from the master.


“This first slave node switches its data output CS2 to GND and the second slave node thus has a low level at its CS1 data input. The second slave node then takes the address from the LIN configuration message and switches its output CS2 to GND. These steps are repeated until all slave nodes have an address,” the engineering rep added. (Note: figure 10 demonstrates this method with an ambient light control application using the ATA6641/42).

Interested in learning more? Part one of this series can be read here and part two is available here.

Designing next-gen LIN systems with Atmel (Part 2)

In the first part of this series, Bits & Pieces took a closer look at LIN, or Local Interconnect Network for vehicles. The LIN bus standard, found within the latest automotive network architectures, is a low-cost, single-wire serial communication system for distributed electronics in cars and trucks.

Essentially, LIN is highly suited for various body control applications, including power windows, mirrors, smart wipers, door locks, seat/roof/lighting control, lamps and indicators, dashboard instruments, steering wheels, climate and air-conditioning (HVAC) systems, motors, switch panels and sensors.

As we discussed in part one of this series, Atmel offers a next-generation ATA6641/42 System Basis Chip (SBC) with an 8-channel high-voltage switch interface, a LIN2.1 and SAEJ2602-2-compliant LIN transceiver and lowdrop voltage regulator. In addition, the ATA6641/42 boasts an adjustable window watchdog, facilitating the development of inexpensive, low-end, but also powerful slave and master nodes for LIN bus systems meeting the latest OEM requirements.

Two versions are available: the ATA6641 with a 3.3V voltage regulator and the ATA6642 with a 5V voltage regulator. Most features can be configured via the SPI – a 16-bit SPI interface that simplifies and accelerates configuration of the slave/master LIN node for any given application. As you can see below, Figure 3 shows a typical application using the ATA6641/42.


“The ATA6641/41’s switch interface unit consists of 8 high-side current sources. They deliver a constant current level derived from a reference value measured at the IREF pin. This pin is voltage stabilized (VIREF = 1.23V typ.) so the reference current is directly dependent on an externally applied resistor connected between IREF pin and ground,” an Atmel engineering rep told Bits & Pieces.

“The resulting current at the CSx pins is (1.23V/ RIref) x rICS. For example, with a 12K resistor between IREF and GND the value of the current at the CSx pins is 10mA (assumed IMUL = `0´ => rICS_H = 100). Fail-safe measures are able to detect both a missing as well as a short-circuited resistor. If a resistor is short-circuited, an internally generated reference current IIREFfs is used to maintain a basic level of functionality.”

Each switch input boasts a high-voltage comparator, a statechange-detection register for wake-up, interrupt request generation and a voltage divider with a low-voltage output that can be fed through to the measurement pin VDIV.

In terms of switch control, 8 high-voltage I/O ports form the heart of the ATA6641/42, making it exceptionally well suited for switch control applications with higher ESD requirements. These I/O ports allow highly flexible control of up to 8 single switches or a switch matrix or any combinations of both, as shown in figure 5, supplied by an internal current source of  5mA to 25mA. Three I/O ports can be configured either as current sources (e.g., for switches toward ground) or as current sinks (e.g., for switches toward battery); the other five pins have current sourcing capability only.


The device’s flexible switch monitoring is controlled by the application’s microcontroller (MCU). The implemented state-change detection circuitry allows configuration of each input so that it triggers an interrupt upon state change even during low-power mode. Therefore the respective current source needs to be configured so that it is controlled via the CSPWM pin. A rising edge on this pin enables the current source and delivers a stable switch read-back signal at the CS pin; a falling edge updates the switch state.

A change of state generates an interrupt request. If no wake-up should occur on a given switch—either because there is no application demand for this, or due to a failure, e.g., a hanging switch or a shorted connection line—wake-up can be prevented by disabling the current source in the SPI configuration register.


If switches are placed outside and connected via a wiring harness to the ECU, complete diagnosis of short-circuits or cable breaks can be performed. Ports that are not used for switch detection can be switched off. The device also features a high-precision current source for multi-resistor coding, while the scan current through the switches can be chosen to be sufficiently high so that the current will clean the switches.

Want to learn more about Atmel’s ATA6641/42? Be sure to check back for part three of this series, in which we’ll discuss voltage measurement, PWM control, h-bridge relays and LIN auto-addressing. Note: Part one of this series can be found here and part three here.

Designing next-gen LIN systems with Atmel (Part 1)

The LIN (Local Interconnect Network) bus is a vehicle standard used within the latest automotive network architectures. The low-cost, single-wire serial communication system for distributed electronics in vehicles is highly suited to body control applications, including power windows, mirrors, smart wipers, door locks, seat/roof/lighting control, lamps and indicators, dashboard instruments, steering wheels, climate and air-conditioning (HVAC) systems, motors, switch panels and sensors.

“It is primarily used as a cost-effective sub-network of a CAN bus to integrate intelligent sensor devices or actuators where the LIN master node also acts as a gateway to connect the LIN bus with the corresponding CAN bus,” an Atmel engineering rep told Bits & Pieces. “Going hand in hand with rapid LIN market growth, the requirements for greater system efficiency and lower costs exerted on LIN products have continued to increase as well.”

To be sure, in-vehicle electronic systems are rapidly evolving and increasing in number, as are the number of switches for controlling various applications. In addition, applications with switches located far away from the control electronics and wires integrated within the wiring harness require high-voltage switches.


“And that is precisely why Atmel offers a next-generation ATA6641/42 System Basis Chip (SBC) with an eight-channel high-voltage switch interface, a LIN2.1 and SAEJ2602-2-compliant LIN transceiver and lowdrop voltage regulator,” the Atmel engineering rep continued. “The ATA6641/42 also boasts an adjustable window watchdog, facilitating the development of inexpensive, low-end, but also powerful slave and master nodes for LIN bus systems meeting the latest OEM requirements.”

Due to its optimized architecture, the ATA6641/42 provides a high degree of flexibility for deployment in various applications such as switch connection through the wiring harness, port/contact monitoring, contact cleaning, switches (towards GND or VBAT) and LED/relay/power transistor control.

Two versions of the System Basis Chip are currently available: the ATA6641 with a 3.3V voltage regulator and the ATA6642 with a 5V voltage regulator. The voltage regulator delivers up to 80mA load current. Sleep mode and active low-power mode guarantee very low current consumption even in the case of a floating bus line or a short circuit on the LIN bus to GND. To maintain very low current consumption in sleep mode, a special technique ensures that the circuit switches back to sleep mode after approximately 10ms if the bus line is floating or in case of a short circuit.


Improved slope control at the LIN driver ensures secure data communication of up to 20kBaud, while data rates of up to 250kBaud also enable high-speed data communication. Most features can be configured via the 16-bit SPI interface which streamlines and accelerates configuration of the slave/master LIN node for any given application.

Want to learn more about Atmel’s ATA6641/42? Be sure to check out part two and three of this series.

Hot August Nights Fever? Atmel Automotive Infographic

People love their cars. It’s one of those near universal facts. Whether they live in big cities or small rural hamlets, drive a mini or a hummer, there is just something about the sexy vroom vroom of an engine that excites people on a primal level.

Perhaps it’s the destructive force in us that is drawn to what is basically a controlled explosion on wheels. Perhaps it’s something to do with an automobile’s sleek and contoured chassis – or the human need for speed.

Or maybe, it’s because there is a certain zen to be found in tinkering with an engine. Of souping up and optimizing an already lean, mean machine, and making it purr. Somewhere in all of us is an engineer who simply wants to solve puzzles – and what greater puzzle to solve than the many moving parts to be found under the hood?

We at Atmel are especially passionate about the automotive space, having been one of the first semiconductor companies to enter the market, embracing both the productive and the creative passion from the get-go.

Atmel_August Auto_Final

Telefunken (the pre- predecessor of Atmel Automotive) was founded as early as 1903, while the Heilbronn fab in Germany, acquired by Atmel in the 1980’s, was founded way back in 1960.

Atmel’s first success in automotive was (rather fittingly) the electronic ignition IC which, in 1979/1980, was installed in every Volkswagen car.

Another early milestone along Atmel’s automotive roadmap was, ironically, braking. A start-to-stop scenario, so to speak.

The market for connected vehicles is expected to grow to a whopping $53 billion by 2018, with consumers demanding more and more connectivity each year.

A study by Deloitte in 2011 determined that 46% of people between the ages of 18-24 cited connectivity as being “extremely important” to them when it came to cars, with 37% wanting to stay as connected as possible while in their vehicles. A resounding 65% identified remote vehicle control as an important feature in their next automotive purchase; while 77% favored remote diagnostics minimizing dealer visits. And let’s face it, who can blame them?

A 2013 study by Cisco went even further, positing that Vehicle-to-vehicle (V2V) communications could enable cars to detect each other’s presence and location, helping avoid accidents, lower road costs and decrease carbon emissions. The report also found that intelligent cars would lead to 7.5% less time wasted in traffic congestion and 4% lower costs for vehicle fuel.

With over 1 billion passenger cars careening through the world’s streets already, increased digitization can’t come fast enough!

Today, Atmel supplies all 10 of the top 10 tier 1 automotive electronic suppliers in the world, not only with microcontrollers (MCUs), but with touch sensor technology too. Indeed, Atmel’s latest touch innovation, the bendable, flexible, printed wonder that is Xsense, has now been fully qualified and is ready to ramp, meaning sexy curved glass dashboards are closer than you’d imagine… Not bad for a feature originally developed as a piece of wood attached to the front of a horse drawn carriage to prevent mud from splattering the driver!

Atmel is also renowned for being a leading car access supplier, meaning we make the chips that enable cool remote keyless entry (RKE) systems with immobilizers, to reduce the risk of anyone stealing your steel beauty away from you. In fact, Atmel has already delivered over 250 Million ICs for this specific application, so that’s a whole lot of key fobs! Speaking of key fobs, here’s a fun fact; holding a remote car key to your head doubles its range because the human skull acts as an amplifier.

Moving from cool keyfobs to total hotness, it’s also worth noting that Atmel sells some of the highest temperature resistant parts in the market, some of which can handle heat of up to 200°C.

Last, but certainly not least, Atmel boasts the world’s largest portfolio of Local Interconnect Network (LIN) devices, for communication between components in vehicles. The firm’s devices have OEM approvals from all major car manufacturers worldwide, which is certainly something to be proud of.

So next time you find yourself on that long and winding road, kicking into high gear and hugging those curves, spare a thought for the components, because when it comes to cars, the devil really is in the details.