Real-Time Operating Systems (RTOS)

All major vendors of Real-Time Operating Systems (RTOS) support ARM architecture.

Many embedded systems require software to respond to inputs and events within a defined short period. Such systems can be categorized as hard real-time, where missing a response deadline is unacceptable (for example an anti-lock braking system), and soft real-time, where hitting a deadline is desirable but not critical. In both types of system, a degree of determinism is important.

RTOS is designed to control an embedded system and deliver the real-time responsiveness and determinism required by the controlled device. Applications run under the control of the RTOS, which schedules allocated CPU time.

In modern systems, a RTOS consists not only of a real-time kernel, but also higher-level functions such as device management (USB, UART, Ethernet, LCD, etc.), file systems, protocol stacks (CAN, TCP/IP, HTTP, etc.) and graphical user interfaces (GUI).

ARM Advantage

The ARM architecture is particularly well suited to the real-time and deterministic requirements of embedded systems, and the implementation of RTOS running on those systems:

• Small code footprint, allowing an RTOS to run from onboard memory
• Fast interrupt response to reduce context switching overhead
• Semaphore support via exclusive load-and-store instructions
• SVC instructions and exceptions to support privileged state operation for the RTOS kernel
• Separate stack pointers for each processor mode for easier memory management
• Sleep modes to minimize power consumption

Whatever your application, you are sure to find a comprehensive list of RTOS vendors who support the ARM architecture.

RTOS Vendors

The ARM architecture is supported by all popular RTOS vendors in the embedded market. Below is a table showing the RTOS companies, their products, and an indication of which ARM processor families they currently support: