Model Behavior

“HAD WE BUT WORLD ENOUGH, AND TIME…”

Seventeenth century poet Andrew Marvell had commitment issues in mind when he penned his often-quoted ode, but the line may resonate with design engineers on tight schedules coping with ever more complex microcontrollers. Help is at hand, or just around the corner, promise vendors of application software and hardware design tools. Standards such as AUTOSAR (AUTomotive Open System Architecture), OSEK and FlexRay also hold the potential to bring consistency to automotive electronics.

The fundamental issues in automotive electronics application development are cost and quality, which are tightly coupled. “There is an overall trend toward testing further upfront, since the cost of errors rises exponentially if they are not discovered until a vehicle reaches the production floor, or gets into a customer's hands,” noted Rod Line, director of marketing at ETAS.

“The big trend, primarily for 32-bit microcontrollers (MCUs), is toward modeling, because it helps OEMs and tier one suppliers reduce development and validation time and cost,” added Paul Fox, director of marketing for the Automotive Business Unit at Renesas Technology America. “They can do preliminary code validation before they build hardware. The evolution from assembler to C code was a really big change, and the shift from C code to modeling, with automatic code generation, will be monumental.”

Today's vehicles contain more electronic control units (ECUs) than ever before but they also contain more electromechanical de-vices such as solenoids, sensors, and electric motors. The interaction between control circuits and electromechanical devices must be understood in order to provide a robust design. “The magnetic fields generated by the opening and closing in an actuator can affect the load on a circuit and may cause it to behave differently from the way it was designed,” said Zoltan Cendes, chief technology officer of Ansoft Corporation. “This is in-creasingly true as frequencies get higher and devices get smaller.”

According to Cendes, the complexity of today's designs is such that a piecemeal approach to validation is no longer sufficient for OEMs and tier one suppliers to meet today's quality standards. “System integration is needed in which control circuitry and electromechanical components are simulated simultaneously and engineers can observe the affects these different devices have on each other,” he said, adding that system integration combines the strengths of finite element analysis (FEA) and circuit simulation without requiring the end user to be an expert in both.

Freescale Semiconductor uses RAppID, a graphical application designed to help engineers get started with Freescale MCUs (Figure 1). “As the customer uses the application, he or she creates documentation and generates code,” said Salim Momin, director of the company's “Virtual Garage” software and services business unit. “The customer benefits from our learning experience, and we get customer feedback.”

Tools vendor dSpace hopes to seize metaphorical high ground with a system-level tool called SystemDesk for model-based development. Planned for introduction in mid-2007, SystemDesk promises to help developers keep track of the planning, implementation and integration aspects of complex system architectures and distributed software systems. It will support AUTOSAR and other standards, and include libraries for storing reusable objects, version control systems, and a scripting-capable tool. SystemDesk will work with dSpace's TargetLink, which can be used to generate production code for software components in SystemDesk architecture models.

dSpace technical support supervisor Santhosh Jogi said vehicle manufacturers can produce the basic design of distributed ECU software and extract the specifications that are relevant for each supplier. System models can be imported and exported so that manufacturers and suppliers can use and maintain them jointly.

Mentor Graphics, which focuses on design automation tools for field-programmable gate arrays, printed circuit boards and embedded software functions, also sees a need for processes, methodologies and tools to manage electronic systems from design to warranty, according to Enrique Ortega, market director, transportation sector, Americas.

The company's life-cycle solutions include CHS for electrical distribution systems and Volcano for designing and testing in-vehicle networks. “Solutions are required that address vehicle electrical design from a holistic point of view as opposed to concentrating only on ECU or components development and their integration into the vehicle from the bottom up,” Ortega said.

“Modern design automation systems address the development of reusable systems, their integration, network strategy, and interconnect synthesis taking into account vehicle complexity and collaboration across the extended enterprise.”

The latest addition to Mentor's CHS software is Capital HarnessXc, its next-generation harness design solution. Mentor claims that it is the first design-to-manufacture tool that solves the challenge of managing change in a controlled and configurable way. It employs Internet-based integration technologies and a unique data-driven graphical styling engine, thereby enabling users who serve different organizations across multiple locations to work with common tools and processes.

Also taking a top-down approach, Dassault Systèmes' ENOVIA MatrixOne unit last December launched the MatrixOne Automotive Accelerator for Program Management (APQP), an assortment of business process applications with industry-specific terminology, data models, pre-defined work processes, reports and role-based user interfaces.

The company said APQP can help companies develop global vehicle product programs with the Advanced Product Quality Planning (APQP) process; track and manage deliverables, and communicate changes to key stakeholders. It also provides a management dashboard with visibility into related projects and supplier deliverables.

In-vehicle software (IVS) data-management systems added to UGS Corporation's Teamcenter enables companies to treat embedded software as a separate component, thus helping to manage software bills of materials (BOMs) and interdependencies between the software and other electronic and mechanical components from design through deployment of embedded software content.

“Our key customers in the automotive industry tell us that change management and traceability are critical challenges,” said Megan Miller, automotive segment manager at Data I/O Corporation. She said the Automotive Performance Programming System the company launched in February is intended to address those requirements.

Available for the company's PS588 or PS288 series production programming systems, the automotive system encompasses a remote monitoring application (PS FlashCORE), statistical process control (SPC) tracking system (PS extended job log), and archived job file (FlashCORE version control).

The PS FlashCORE system lets a manager or customer monitor statistics and current production activity on up to five networked programming systems. The Job Log tracking system provides detailed information on every motion of a device during the programming process. The Version Control system creates a file with reference to all software components used in the approved first article release. “It gives production managers strict configuration control over data file and programming task management,” Miller said.

The AUTOSAR consortium announced the end of phase one development last October with the pending publication of Release 2.1 specifications. The consortium has defined the operating system, communication, hardware abstraction, and runtime environment, all of which sets the stage for application development.

Software compliant with the 2.0 specification is undergoing validation, and the first production vehicles containing AUTOSAR technology are expected as early as 2008. In phase two development, under way, the consortium will address new areas including safety and multimedia/telematics.

“Time constraints get shorter while quality demands grow higher,” said Gary English, engineering group manager for software architecture and building blocks at Delphi Electronics Safety Division. “The AUTOSAR consortium has done a good job of agreeing on the basic software layers, including the runtime environment (RTE). It's the foundation that the application layer people need, and it's a pretty big deal. As we're able to converge to a common architecture, software engineering becomes more interesting.”

“AUTOSAR is trying to communize a lot of abstraction layers. It levels the playing field among microcontroller suppliers,” noted Renesas' Paul Fox. “(AUTOSAR) takes away some advantages, but we fully support the AUTOSAR and JasPar efforts,” he said.

AUTOSAR allows a building block approach to application development and tools vendors are focused on supporting the standard. The Mathworks, for example, has promised to define, document and demonstrate how engineers can use current versions of Mathworks products such as Simulink, Stateflow and Real-Time Worshop Embedded Coder to generate software components able to interact with the AUTOSAR RTE.

Mike Inglis, executive vice president for marketing and business development at ARM, said his company had AUTOSAR in mind when it designed the Cortex-R4F automotive processor. He said the device permits tight control over independent software tasks, a capability critical for the AUTOSAR RTE bus and also for applications based on the OSEK standard for an open-ended architecture and the JasPar automotive software platform architecture.

“AUTOSAR builds an infrastructure component model on the OSEK operating system,” said David Smith, a scientist at Synopsys specializing in design and simulation of automotive and aerospace systems and chairman of the Society of Automotive Engineers (SAE) electronic design automation (EDA) committee.

“There has been an explosion of processors — as many as 80 to 100 in a vehicle,” Smith said. “OEMs want to reduce that number and don't want a dedicated CPU for each subsystem. The goal of AUTOSAR is getting vendor A and vendor B to coexist in the same ECU.”

Synopsys's Saber software (Figure 2) simulates physical effects in hydraulic, electronic, mechanical, thermal and other engineering domains as well as signal-flow algorithms and software control. Saber is used to simulate and analyze systems, subsystems and components under a variety of operational and environmental conditions. Its objectives are to improve design reliability and reduce the need for physical prototypes.

Synopsys has expanded its collaboration with UGS to enable tighter integration between its Saber Simulator and Saber Harness software and UGS Corp.'s Teamcenter collaborative product data management (cPDM) and NX mechanical CAD (MCAD) software solutions. As a software partner in the UGS Partner Program, Synopsys now has a “Foundation” specialization, which ensures that UGS customers get an integration scheme that can be maintained and improved by UGS and Synopsys. This integration will enable the effective delivery of complementary electromechanical solutions critical to modern automotive designs.

Like AUTOSAR, the FlexRay network protocol is poised for mainstream acceptance. BMW is using FlexRay for a suspension application in its X5 SUV. Agilent Technologies and Dependable Computer Systems GmbH (DECOMSYS) recently launched a FlexRay measurement system consisting of an Agilent 6000 series mixed-signal oscilloscope and a DECOMSYS::BUSDOCTOR 2 protocol analyzer (Figure 3). The system provides frame, slot and error triggering capabilities, allowing engineers designing embedded MCU applications to verify the integrity of FlexRay signals and the proper timing of the time-triggered communication bus.

Microcontroller suppliers have an obvious interest in making their devices easy to use. Microchip Technology stresses the reusability of code based on the fact that it offers pin-compatible families of devices. Members of an 8-bit family, for example, offer memory configurations ranging from 4 k to 64 k, with each device in a 28-pin socket.

Willie Fitzgerald, director of marketing for Microchip's Automotive Products Group, said the company offers embedded application designers a variety of development boards, in-circuit emulators and debuggers and other programming aids. In February, Microchip enhanced its MPLAB Integrated Development Environment (IDE) with a free plug-in for The MathWorks' MATLAB, Simulink and Real-Time Workshop Embedded Coder modeling and code-generation programs.

Texas Instruments provides a SystemC simulation tool that customers can use during early-phase development to determine how a microcontroller should be specified, and to start writing code. It also offers a GUI-based tool called HalCoGen that lets engineers determine MCU pin connections. The tool automatically generates software peripheral drivers.

Matthias Poppel, automotive marketing manager in TI's advanced embedded control group, said the company supports in-circuit and invasive MCU emulation tools. “Trace debug and calibration requirements are becoming more stringent,” he said.

“It used to be common to read data serially, which meant stopping the CPU to reload code and change parameters. We still support that, but we have also taken the effort to make real-time trace debug possible. The CPU keeps running while data is being read, and new parameters can be written into flash to check the effect of those parameters on the software and the application. The trend is to have emulation capabilities on production devices.”

Freescale Semiconductor's Momin said the company's “Virtual Garage” offers system-level tools, silicon support tools and engineering services to help customers specify and validate designs in a virtual environment prior to production.

“Our high-end MCU has more than 1,700 programmable registers, plus peripherals that the automotive industry is not used to,” Momin said. “The manual is 1,000 pages. If we were simply to give a manual and a compiler to an engineer it would probably take them a couple of months before they were able to write their first line of code.”

Change is under way in computer-aided design as well as in embedded applications programming. “The CAD market has evolved from 2-D to 3-D in the past five years,” said Stan Nowiki, North American PLM support manager at Siemens VDO. “The cutting edge of CAD is visualization. In the last couple of years, JT has become a quasi-standard. We can take JT files from different suppliers, created on different CAD systems, put them together, and see the result. Visualize part of an engine or a dash. Previously, there was no easy way to do this unless everyone used the same CAD tool and the same data format.”