Targeting complex, safety-critical applications, Texas Instruments has introduced the TMS570F, one of the first ARM Cortex-R4F processor-based floating point, lock step, dual-core automotive MCUs. Based on two Cortex-R4F processors, the TMS570F MCUs were designed specifically for applications required to meet the International Electrotechnical Commission (IEC) 61508 SIL3 or ISO26262 ASIL D safety standards.
"According to Strategy Analytics, the number of microcontrollers per car is forecast to double by 2012," said Wayne Lyons, director, embedded solutions, at ARM. "Added to this growth, the sophistication of safety control functions is expected to increase substantially." "Embedded control will continue to be a primary driver of high-end automotive microcontroller performance and functional development," added Strategy Analytics senior analyst Mark Fitzgerald, "However, going forward, multi-sensor advanced driver assistance system applications will increasingly emerge as high-performance processor drivers. As a result, multi-core designs will increase for greater computational performance."
The TMS570F allows automotive system designers to implement single and double precision floating-point math depending on performance requirements. Accelerated multiply, divide and square root functions enable physical model-based control through development environments like The Mathworks Real Time Workshop and ETAS ASCET. Such graphical-based environments help engineers accelerate complex safety application designs and add differentiation through custom vehicle control algorithms for unique handling, ride and user experience.
According to TI, as the demand for differentiated, safety-critical automotive applications increases, MCU-based systems that can meet these performance demands via integrated, intelligent systems will become increasingly important. Developers typically begin creating algorithms in a floating point environment for validation, and then convert the code to run on fixed-point devices. Using the TMS570, developers can eliminate weeks or months of time contending with scaling, saturation and adjustment of numerical resolution required in fixed point implementations.
The dual-core lockstep implementation also simplifies software development by removing redundant safety system requirements. Hardware built-in self test (BIST) of both memory and CPU functions further increases integration and lets designers detect latent defects without using safety software drivers that reduce performance and have significant code size overhead. TI said that hardware comparison of the CPU's outputs provides on line diagnostics with exceptional safety response time and no additional software overhead.
The TMS570F is designed to meet error-free automotive safety standards and provide system-wide protection through seamless support for error detection from the processor, through the interconnect and into the memories. Error correction code (ECC) logic is integrated into the CPU, which protects both the memories and busses. Because ECC is evaluated within the CPU, the system takes advantage of the eight-stage pipeline to allow time for ECC evaluation with no performance impact. In the event of a memory error, the ECC logic will correct it, rather than just communicating the error and stopping the system.
Exida Consulting LLC performed a detailed review of TI’s development processes and conducted a reliability analysis. Exida chief executive officer Bill Goble said the TMS570PSFC66 meets all of the relevant SIL 3 requirements of IEC 61508. The TMS570F MCU platform uses two identical ARM Cortex-R4F processors combined with an initial two Mbytes of on-chip flash memory. Industry standard peripherals include a FlexRay protocol controller; up to three CAN and two LIN modules, along with TI's high-end timer co-processor, and two 12-bit analog to digital converters (ADC).
Targeted applications include chassis control, braking, electronic vehicle stability and steering as well as advanced driver assistance with higher and lower memory and performance variations in development. TI said its ARM processor-based TMS470 MCU is used in the majority of automotive safety systems such as antilock braking systems, electronic stability control systems and airbag electronics.
TI also offers digital signal processors for infotainment, navigation, and vision- and radar-based driver assist systems, and mixed signal solutions that integrate analog, power, and digital circuits.
The TMS570F is currently available in 324 BGA packaging with additional package options of 144 and 176 LQFP as well as 256 BGA planned. Suggested pricing in 10ku per year quantities is $25.75.