CompactPCI Serial has proven to be a beneficial technology upgrade for a number of embedded systems designers accustomed to working with the legacy CompactPCI platform. Not only does CompactPCI Serial bring modern serial interfaces and a ruggedized connector scheme into play, but it also provides significant cost advantages while adhering to many known design principles, lessening a developer’s need to learn a new and complex technology.
It’s no wonder CompactPCI systems have proliferated during the last few decades. They can be built using standard components and can run practically any operating system as well as thousands of application software packages without modification. Because of this, CompactPCI is a widely accepted — and utilized — technology platform in countless markets from telecommunications and computer telephony to industrial automation, real-time data acquisition and military systems.
When CompactPCI started failing to keep pace with current computing requirements, it seemed a shame to just toss aside a proven technology in favor of a different computing scheme. Instead, those computing needs were evaluated, the platform was modified and a solid, cost-effective, long-term solution was formed, positioning CompactPCI as a viable platform for applications well into the future. Thus, CompactPCI PlusIO and CompactPCI Serial were born.
A Trifecta of Computing Specs
Part of the quick adoption rate of CompactPCI Serial (PICMG CPCI-S.0) is due to its sister specification, CompactPCI PlusIO (PICMG 2.30), which enables the migration from legacy CompactPCI (PICMG 2.0) to serial-based systems, as time and money allow. CompactPCI PlusIO forms a link between the old and the new. This new family of specifications is a well-rounded set that incorporates the past, present and future needs of embedded computing systems using CompactPCI technologies (Figure 1).
From the beginning: As data requirements in embedded systems began to increase, CompactPCI systems were limited to a parallel bus design, yet system designers were being called on to provide greater bandwidth and higher data transfer rates among the input/output (I/O) resources. Older systems could not take advantage of the high-speed serial point-to-point communications needed to move all system information along effectively.
The challenge was developing a new standard that preserved the large number of installed CompactPCI-based systems as well as the knowledge base of designers already familiar with CompactPCI, while bringing systems in line with current data requirements. This was addressed by developing two separate standards, CompactPCI PlusIO and CompactPCI Serial, to move CompactPCI-based systems into the modern era.
Designed with a purpose: CompactPCI PlusIO was deliberately developed using the same 19" mechanics as legacy CompactPCI, while allowing for the integration of serial-based systems. This very calculated adaptation of the original specification addressed the challenges of maintaining existing systems, and therefore the time and money invested in those systems. It also preserved the reliability, robustness and maintenance-friendly attributes of the original CompactPCI.
While compatible with the interim CompactPCI PlusIO solution, CompactPCI Serial is geared towards completely new systems based solely on serial communications. But because of the link through the CompactPCI PlusIO structure, older systems can implement serial technologies on an as-needed basis — whether driven by functionality requirements or budgetary considerations.
The pivotal change in CompactPCI PlusIO that enables the legacy systems to work with serial-based ones is the use of an Ultra Hard Metric (UHM) connector with specific features to accommodate the performance demands of serial communications. While accommodating the high-speed signals increasingly required in today’s embedded systems, the new UHM connector still mates with the hard metric headers currently used in original CompactPCI system backplanes, enabling operation in legacy systems (Figure 2).