Classic Platform (CP):
The Classic Platform is AUTOSAR’s solution for embedded systems with hard real-time and safety constraints. Its architecture distinguishes on the highest abstraction level between three software layers which run on a microcontroller: application, runtime environment (RTE) and basic software (BSW), and we are going discuss these layers deeply in the next posts.
Let’s disscuss some of CP characteristics :
- The application software layer is mostly hardware independent.
- Communication between software components and access to BSW via RTE.
- The BSW is divided in three major layers and complex drivers:
- Services, ECU (Electronic Control Unit) abstraction and microcontroller abstraction.
- Services are divided furthermore into functional groups representing the infrastructure for system, memory and communication services.
- The Classic Platform is AUTOSAR’s solution for embedded systems with hard real-time and safety constraints.
Adaptive Platform (AP):
The Adaptive Platform is AUTOSAR’s solution for high-performance computing ECUs to build safety-related systems for used cases such as highly automated and autonomous driving, and develop ECU applications independently of one another in distributed work groups.
Let’s disscuss the limits of CP and why we goes to AP:
- The increasing number of cores overwhelms the design of CP, which was originally designed for a single core MCU, though it can support multicore.
- Also, the power efficiency is already becoming an issue even in data centers, and it is in fact much more significant for these intelligent ECUs.
- From processor technologies point of view, physically not possible to increase the processor frequency endlessly and the only way to scale the performance is to employ multiple (and many) cores and execute in parallel.
- Also, it is known that the best performance-per-watt is achieved by mix of different computing resources like manycore, co-processors, GPU, FPGA, and accelerators. This is called heterogeneous computing certainly overwhelms the scope of CP by far.
It is also worthwhile to mention that there is a combined effect of both processors and faster communications.
AP provides mainly high-performance computing and communication mechanisms and offers flexible software configuration, e.g. to support software update over-the-air.
AP Main Characteristics:
- C++
The applications can be programmed in C++. Should bring the faster adaptation of algorithms and improve application development productivity. - service-oriented-architecture (SOA)
The SOA is based on the concept that a system consists of set of services, in which one may use another in turn, and applications that uses one or more of the services depending on its needs - Parallel processing
AP owns the architectural capability to scale its functionality and performance as the manycore-heterogeneous computing technologies advance. - Leveraging existing standard
AP takes the strategy of reusing and adapting the existing open standards, to facilitate the faster development of the AP itself and benefiting from the existing standards. (no new interfaces introduced). - Safety and security
The architecture is based on distributed computing based on SOA, which inherently makes each component more independent and free of unintended interference, dedicated functionalities to assist achieving safety and security, and guidelines such as C++ coding guideline, which facilitates the safe and secure usage of complex language like C++. - Planned dynamics behaviors
a. Restriction of dynamic memory allocation to startup phase only
b. Fair scheduling policy instead of priority-based scheduling
c. Fixed allocation of processes to CPU cores
d. Access to pre-existing files in the file-system only
e. Constraints for AP API usage by Applications
f. Execution of authenticated code only - Agile
“AP will not replace CP or Non-AUTOSAR platforms in COTS. Rather, it will interact with these platforms and external backend systems, to form an integrated system”
Sincerely,
Amr Ashraf
Embedded Software Engineer
Embeddive 