The ARM cortex is the latest arm embedded core based on the ARM7V architecture, which uses the Harvard architecture, using separate instructions and a data bus with the von Neumann structure, which uses a single line of information and instructions. In essence, the Harvard structure is more physically complex, but the processing speed is significantly faster.
According to Moore's theorem, complexity is not a very important thing, and the increase in throughput is of great value. ARM's position on cortex is to provide low-cost, low-power chips to the professional embedded market. Cortex has fairly good performance in terms of cost and power, and Arm believes it is particularly well-suited for the automotive and wireless communications sectors.
Like all arm cores, ARM has licensed the design to individual manufacturers to develop specific chips. So far, a number of chipmakers have started to produce microcontrollers based on the cortex core. This type of kernel has been around for more than 10 years and has driven the arm to become the leader in the processor core domain.
Numerous manufacturers sell processors based on the ARM7 series and other supporting system software, development and commissioning tools. In addition to using the Harvard structure, Cortex has other notable advantages: a smaller base core, lower prices and faster speeds.
Integrated with the kernel are some system peripherals, such as interrupt controllers, bus matrices, and debug function modules, which are usually added by chip manufacturers. The cortex also incorporates a sleep mode and an optional complete eight area memory protection unit. ARM7 can use arm and thumb two instruction sets, while Cortex only supports the latest Thumb-2 instruction set. The advantage of this design is that it eliminates the switch between thumb and arm code, which can degrade performance for earlier processors.
The Thumb-2 instruction set allows users to maintain and modify applications at the C code level, and the C code section is very easy to reuse. The Thumb-2 instruction set also includes the ability to invoke assembly code: Luminary Company does not consider it necessary to use any assembly language. Combined with these advantages, the development of new products will be easier to achieve, time-to-market is greatly shortened.
Another innovation in cortex is the nested vector interrupt controller Nvic Nested vector Interrupt Controller. In contrast to the external interrupt controller used by the ARM7, the cortex core incorporates an interrupt controller that can be configured by the chip manufacturer to provide a basic 32 physical interrupt with 8 levels of priority, up to physical interrupts and interrupt priority.
This type of design is deterministic and has low latency, and is ideal for automotive applications. Nvic is using a stack-based exception model. When processing interrupts, the program counters, program status registers, link registers, and universal registers are pressed into the stack, and after the interrupt processing is complete, the registers are restored.
Stack processing is done by hardware and does not require assembly language to create a stack operation for the interrupt service program. An interrupt nesting can be implemented. Interrupts can be changed to use a higher priority than the previous service program, and can change the priority state at run-time. Using the end-of-chain tail-chaining continuous interrupt technology consumes only three clock cycles, which significantly reduces latency and improves performance compared to 32 clock cycles of continuous pressure and out stacks.
If the Nvic has already pressed the stack before the higher-priority interrupts arrive, it is only necessary to get a new vector address that can serve the higher-priority interrupts. Similarly, Nvic does not use the stack operation to serve new interrupts. As of , more than billion ARM-based processors have been created.
Based on this information, ARM solutions are the most widely used processors on the market. Their amazing capabilities and the variety of solutions that suit specific needs has resulted in these devices attracting much attention. We will highlight general information, areas of application, and the main characteristics of representatives of the A, R, and M types of processors.
Different ARM Cortex controllers exhibit particular scalability and performance features that are most suited to specific applications. Now, users do not have to make undesirable choices and surf from one unacceptable solution to another.
The Cortex-A category of processors is dedicated to Linux and Android devices. Any devices — starting from smartwatches and tablets and continuing with networking equipment — can be supported by Cortex-A processors. The Cortex A5 is the smallest processor of the A-range, but it can still demonstrate multicore performance. In terms of power consumption, the A5 and A7 processors are nearly the same.
The Cortex-A7 finds its application in smartphones and tablets and is famous for its power optimization technology. It is compatible with the A15 and A The Cortex-A15 has the highest performance among the members of this set. The A15 processor finds its application in high-end devices, low-power servers, and wireless technologies.
This is the first processor in the range that fits data management and virtual environment solutions. The effectiveness of the Cortex-A17 is impressive. This is why its main aim is satisfying the needs of premium-class devices. The processor can be configured with 1—4 cores with out-of-order pipelines. An A17 in combination with an A7 creates the big. This is the latest series produced by the company.
The Cortex-A50 processor extends the areas of application to low-power servers. It demonstrates useful power-optimized features and creates great conditions for the migration of bit operating systems to mobile solutions.
Cortex-R processors primarily target real-time solutions. They find application in controllers, networking equipment, media players, and other similar devices. Furthermore, this type of ARM processor provides great support for the automotive industry. Cortex-R processors have a lot in common with high-end microcontrollers, but at the same time have the ability to fulfill more scalable tasks.
The Cortex-R4 microcontroller can be clocked to MHz. Its main characteristics are a dual-issue 8-stage pipeline and prefetch prediction. R4 controllers can quickly handle any incoming interruptions. This type of processor takes care of networking and data storage.
It extends the set of R4 features by adding improved efficiency and reliability. The dual-core implementation of the Cortex-R5 allows the construction of strong systems with lightning-fast response. The processors from this category demonstrate very high performance. They are optimized for low cost rather than high performance. They are mostly used to control hardware, and programmed either bare metal without libraries or linked with some libraries that could provide OS-like features. They are optimized for high performance rather than low cost but still optimized for high performance per unit of power.
They are generally sold as micro-processor often combined with high-end peripherals like ethernet, video, mpeg decoder , intended to be combined with off-chip RAM and FLASH. They often run some OS, often Linux, with a separation between OS space and space for application programs. Very short summary: M is for high-end micro-controllers, A is for running Linux on battery-powered gadgets. Sign up to join this community. The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Ask Question.
Asked 6 years, 5 months ago. Active 3 years, 1 month ago. Viewed 16k times. Add a comment.
0コメント