Not only have medical instruments and devices become increasingly complex, but accountability for every bit of software used in these critical designs is key.
While it is the end device and not the software that is ultimately certified and approved by the FDA, the embedded software itself plays a crtical role in the certification process. As such, the selection of an RTOS for a medical device can be challenging. At a bare minimum, you want embedded software that allows developers to efficiently design applications while supporting the most popular processing platforms quickly and easily. But there's so much more to it than that. Field-proven reliability, high-quality documentation, cleanly written, and well-structured software that is backed by a ready-to-act support team are paramount. Weston Embedded Solutions software offerings are right at home for use in the medical industry.
Weston Embedded Solutions’ stringent development process, strict coding standards, code reviews, and clear, concise, and exhaustive documentation have enabled the Cs/OS2 kernel to meet the requirements of use within functionally certified products for medical applications. The RTOS is ideal for use in such safety-critical products as medical FDA 510(k), Class III medical devices, and SIL3/SIL4 IEC-certified systems.
Developers who choose Weston Embedded Solutions for their projects receive proven software that has a rich history of deployment in certified medical devices. They also gain access to an industry-leading support team. With this combination, we have become the RTOS provider of choice for many of the medical device field's leading companies.
A Lightweight Solution
Many medical applications target home heath care or wearable devices that are produced in extremely high quantities and can be highly cost sensitive. All Cesium RTOS software modules are written specifially for embedded systems and designed to use limited resources efficiently. Cesium's Cs/OS kernels can be configured easily to use 6 kBytes (or less) of code space.
This compactness explains why the kernel continues to find use in products with MCUs of 16 kBytes or less of on-chip Flash, even as many of its users have migrated to parts with more-generous memory allocations. Software with a small, efficient memory footprint is critical for high-volume products where additional memory chips can have serious cost consequences.
As battery life expectations from healthcare consumers have grown, it has become increasingly important for developers to minimize their product's power consumption. We have long recognized that effective power management requires a holistic approach: the selection of the right MCU, development of application code that fully leverages that MCU's features, and the use of a power-efficient RTOS.
The power-management features of Cesium's Cs/OS kernels can keep a device running for years without a battery change. These features include hook functions for initiating low-power modes, support for a dynamic tick rate, and even tick-less operation.
A Wealth of Example Code and Documentation
The first phases of a project can often prove to be the most difficult, so we have worked to ensure that developers of medical devices have ample resources to get started quickly.
Weston Embedded Solutions offers a number of example projects for medical device developers. We also provide extensive documentation for these projects in a collection of highly informative books for the µC/OS-II and µC/OS-III kernels and TCP-IP stack, products which are a precursor to today's Cesium RTOS offering. Many of the example projects described in the books are fully functioning prototypes for common home medical devices, such as blood glucose meters and heart-rate monitors.
Hospital and Laboratory Equipment
In contrast to devices used in home healthcare, devices for medical professionals are often low-volume products that leverage the latest high-performance processors.
Safety certification (commonly, the IEC 62304 standard) is a typical requirement for hospital and lab equipment. We have a history of helping developers meet these standards in both home and professional healthcare and boast a user base that includes many of the top names in patient care and diagnostics products.
µC/OS-II, which is the core of today's Cesium Cs/OS2 kernel, has served as the foundation for multiple products that have achieved FDA 510(k) clearance as Class II and Class III devices. It has also been used in products certified as Class C devices under the demanding IEC 62304 standard.
To ensure that developers of medical devices have all the resources needed to navigate the certification process, we work in conjunction with the functional safety experts at Embedded Office. As a result, the range of services and products we offer affords developers complete freedom to select a certification option that balances the time and budgetary constraints of their projects.
Dan Bartnik, Chief Technology Officer & VP of Operations
Our experience with Micrium has been great. Micrium source code is accessible and well documented. Micrium’s RTOS enabled us to easily transition code from our first product to our new SensiLase PAD-IQ platform, because the port of Micrium’s RTOS was already available for our chosen processor.
Designing an electronic healthcare device means managing engineering tradeoffs. On the one hand, medical devices are often too complex to be implemented just with a simple programming loop. But on the other hand, they can rarely afford the heft of a full-blown desktop operating system such as Linux.
The SensiLase PAD-IQ is a perfect example. The PAD-IQ is a mobile medical device that tests patients for peripheral arterial disease. It examines capillaries under the skin using a laser Doppler signal. The PAD-IQ then transmits its measurements to a central database, where the physician can examine the results using a web-based application.
The PAD-IQ runs Micrium’s µC/OS-II to support an application that controls a variety of functions: the laser temperature and current, inflation of blood pressure cuffs, error diagnostics, watchdog management, and test sequencing. Because the PAD-IQ is a mobile device, it needs a real-time operating system that is capable and lightweight.
We selected Micrium because we wanted a reliable and certified real time operating system to serve as one of the foundational components for our next generation of products. We evaluated several products and Micrium provided all of the features we needed and was best suited to our development environment.
Micrium has been outstanding to work with; we have a number of products using software from different vendors and Micrium is certainly a gold standard to measure the others against.