Frequently Asked Questions

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Accellera Acquires Assets of OCP-IP

What does the arrangement between Accellera and OCP-IP involve?

OCP-IP has transferred to Accellera all practical assets of the Corporation including the OCP specification and its entire supporting infrastructure.


What are the benefits of the arrangement?

Combining the established technologies of both organizations instantly provides one-stop, front-end electronic design shopping to a broader audience.


Why was the arrangement undertaken?

OCP-IP sees the industry opportunity to consolidate standardization practices through the established activities of Accellera. Given Accellera’s broad exposure to the electronic design market, the inclusion of OCP and its infrastructure in Accellera’s portfolio is a significant opportunity to capitalize on respective missions, overlapping areas of development and other synergies.


What about annual dues payable/paid at OCP-IP?

Current members at OCP-IP have established equivalent membership classes within Accellera. If you have membership dues already paid to OCP-IP for the current year, you may obtain prorated credit for your membership at Accellera. To clarify your specific situation, please contact:


Lynn Bannister

Phone: (707) 251-9977


If your dues are now payable at OCP-IP, you should direct your membership situation toward this same Accellera contact.


What do OCP-IP members need to do?

Current OCP-IP members should contact Lynn Bannister at Accellera,, to discuss ongoing membership alternatives.


What do Accellera Members need to do?

Nothing is required. As Accellera members, they now have legal rights to access and license the OCP specification and associated infrastructure as part of their current membership.


What happens to working groups at OCP-IP?

Accellera has set up a workspace for the OCP Working Groups within its existing infrastructure. The tools and support that all Accellera working groups receive will be extended to OCP Working Groups.


Can I continue to use OCP?

As an existing licensee to published versions of the OCP specification and its infrastructure, you have the right to continue to use OCP under the terms of that existing license.

How do I get access to OCP in the future?

If you are not a current licensee and you wish to use OCP or any of its infrastructure, you may do so by obtaining licensing rights through Accellera.

When will this arrangement be operational with OCP-IP and Accellera?

The arrangement is operational as of this posting.


Whom do I contact if I have questions?

Lynn Bannister

Phone: (707) 251-9977


1. How did the organization get its name, OCP-IP?
2. What are the key capabilities of OCP technology?
3. What are the advantages of OCP technology?
4. Isn't OCP just another bus interface? Why do we need it?
5. What is the charter of OCP-IP?
6. Why was the organization formed?
7. What is the mission of OCP-IP?
8. Why is a member organization needed to promote OCP technology?
9. How is OCP-IP organized?
10. What is the long-term goal for OCP-IP?
11. Why should ASIC houses, IDM's, IP providers or systems companies join OCP-IP?
12. What is Sonics' role in OCP-IP?
13. Has OCP-IP conducted a patent search to check for patent liabilities surrounding the OCP socket?
14. When will products based on OCP technology enter the marketplace?
15. What are some of the key or most common applications for OCP?
16. How does my company become an OCP-IP member?
17. How can I find out more about OCP-IP's University Program?
18. Do I have to join OCP-IP to use OCP?

General Technical

1. What is the definition of a core?
2. What is the OCP?
3. What comprises OCP?
4. How flexible is OCP?
5. Which interfaces can OCP be used for?
6. How does OCP handle analog signals?
7. Has the OCP been implemented in any other language (SystemC, C++, Fortran, etc.)?
8. Is an OCP connection a peer-to-peer connection?
9. What if two cores require peer-to-peer communication?
10. Wouldn't two OCP interfaces require a lot of die size?
11. Can any two cores with OCP interfaces communicate?
12. What if two cores have similar, but not identical, OCP interfaces?
13. Is OCP really just another bus?
14. What is the OCP word size?
15. How big can the OCP word size be?
16. Is OCP big or little endian?
17. How do I connect my big endian core using OCP?
18. What OCP compliant cores are available?
19. What is an OCP bridge?
20. Does the OCP specification cover scratch pad RAMs?
21. Does the OCP specification support transaction protocols?
22. Does the OCP specification provide templates for common types of interfaces?
23. What OCP Profiles currently exist?
24. How is security handled by OCP?
25. Does OCP provide any support for divided clocks?
26. Does OCP provide any support for cache coherency?
27. Does OCP provide support for power management?
28. How does the OCP disconnect mechanism differ from the OCP reset?

Specification Version

1. Is OCP 2.0 released now? What is the current standard?
2. What differs between the 1.0 and 2.0 versions of the OCP Specification?
3. What differs between the 2.0 and 2.1 versions of the OCP Specification?
4. What differs between the 2.1 and 2.2 versions of the OCP Specification?
5. What differs between the 2.2 and 3.0 versions of the OCP Specification?
6. What is the purpose of lazy synchronization?
7. Which version of the OCP Specification should I use?
8. 2.0 has been referred to as allowing a "minimalist" interface. What does that mean?
9. What parameter controls have responses for write commands?
10. What will be the behavior of an OCP master in the case where the slave generates the response phase for write commands (in posted write model)?
11. How are the master and slave reset signals asserted in different OCP versions?

Relationship to Other Technologies

1. What is the difference between the OCP and standard bus specifications?
2. Is there an existing interconnection topology specifically targeted to the OCP (to bus, hierarchical, crossbar, etc.)?
3. Are there timing or power models of the OCP modules?
4. Is OCP-IP the same as Opencores?
5. How does OCP-IP compare to VSIA?
6. What is the difference between OCP and the VSIA's VCI?
7. Is OCP really a superset of the AVCI?
8. Does OCP-IP offer a simple bridge for BVCI to OCP like its one for PVCI to OCP?
9. What are the differences and what are the advantages OCP has over AMBA?
10. Does OCP-IP provide a design reference for APB and AHB busses?
11. Does OCP-IP offer any core code for PCI-X?
12. PCI supports dual address which means bigger than 32-bit, but OCP only supports up to 32-bit address. Is there any workaround?


1. What is an OCP transfer?
2. What is an OCP transaction?
3. What is the burst model for OCP?
4. What is the difference between an incrementing burst and a streaming burst?
5. What do these burst codes mean?
6. Does the Burst Read timing diagram specify the number of transfers or number of bytes?
7. Why doesn't the burst code equal the number of words left?
8. How does an initiator make sure that a write burst has been committed to its target before it signals another initiator that data is indeed ready?
9. What burst size should I use?
10. The burst size for my core does not match any of the OCP burst codes. What do I do?
11. Can I transfer a burst that is longer than 8 OCP words?
12. Can I end a burst transfer early?
13. Can an OCP initiator abort a burst transfer after it is started?
14. Why would I want to enable burst on my initiator core?
15. What is a Single-Request Multiple-Data (SRMD) burst?
16. How can two-dimensional block burst sequences be handled?

Simulation & Test

1. What is STL?
2. Do I have to use only STL for my QuickCore Model OCP tests?
3. What are the differences in using STL and Verilog for my QuickCore Model OCP tests?
Can I use both STL and Verilog for my QuickCore Model OCP tests?
5. Can I use VHDL for my QuickCore Model OCP tests?
6. If I join OCP-IP, what software do I get?
7. What RTL and simulation languages are supported by CoreCreator?
8. Can CoreCreator be used on Linux based systems?
9. How is OCP compliance testing done?
How do I know if my core is OCP compliant?
What does the OCP protocol checker check for?
12. If my bridge passes OCP check, is it OCP compliant?
13. What are OCP-IP's long-term plans for compliance testing?
14. What types of verification rule sets does OCP-IP provide?
15. What levels of functional coverage are used for OCP compliance testing?
16. Why are there no transfer level functional coverage metrics?

Threads & Connections

1. What exactly are threads?
2. Why use threads?
3. What is the maximum number of threads a core can have?
4. Why would I need multiple threads?
5. What is the timing (relative to the phases) of the MThreadID signals?
6. What is the implication of the master/slave reset on the executing thread?
7. How can a core achieve priority processing?
8. What is the Connection ID on the OCP used for?
9. How do threads differ from connections?
10. Can a single slave be connected to multiple masters? If not, then how are shared memories done? With OCP being a point to point connection, is there a protocol in OCP for connecting multiple processors to a memory controller?
11. What is tagging?
How do tags differ from threads?
13. What kind of flow control can be used with threads?
How do I prevent blocking when multiple threads are used?

Participant Membership/VSIA Status

1. How do I become a member?
2. What benefits do I get from OCP-IP membership?
3. What is the relationship between VSIA and OCP-IP?
4. What are the goals of OCP-IP as a VSIA adoption group?
5. Who will oversee the adoption group?
6. What happens to my OCP-IP membership if I leave VSIA?
7. How do I get all the same benefits of other OCP-IP members?
8. What is an Adoption Group?
9. Why did OCP-IP become a VSIA Adoption Group?
10. How do OCP-IP and VSIA work together?
11. What is the cost of OCP-IP membership?
12. How is the OCP Standard recognized within VSIA?
13. Why do I want to be a member of VSIA?
14. What is the value of OCP-IP working with VSIA?
15. Which VSIA members would want to join OCP-IP?
16. How is OCP different from the VCI standards?
17. Why did VSIA want to work with OCP-IP?
18. What is the benefit to the industry of OCP-IP and VSIA working together?
19. What if I want to continue using VCI?
20. How do I get a copy of OCP?

All FAQs | Organizational | General Technical
Specification Version | Relationship to Other Technologies | Bursting
Simulation & Test | Threads & Connections | Participant Membership/VSIA Status
MetaData Vendor Extensions