OpenPIC standard or MPIC standard document

Where can I get any docum开发者_JAVA技巧ent specifying the OpenPIC and MPIC standard ?

There was never any complete documentation for OpenPIC released. The closest thing was documentation for the for the AMD 19725c OpenPIC controller. It used to be located at http://www.amd.com/html/products/pcd/openpic/19725c.pdf, but it seems that the link is broken and searching AMDs site turns up nothing. Your best bet is probably to look at the OpenPIC source code in the Linux kernel.

As for MPIC, you you can look at the documentation for the Intel 80314 I/O Processor.

Not only is OpenPIC not a standard, there isn't even a spec. There was a spec called "The Open Programmable Interrupt Controller (PIC) Register Interface Specification Revision 1.2", issue Date Oct. 1995, issued jointly by Advanced Micro Devices and Cyrix Corporation. This document is referenced in include/linux/openpic.h. However, the document itself has disappeared.

In addition to the Linux openpic.h, a number of Freescale PowerPC technical references such as the "P1020 QorIQ Integrated Processor Reference Manual" refer to "the OpenPIC architecture", giving the false impression that there is some standard or existing spec.

According to Wikipedia "AMD and Cyrix once used the similar OpenPIC architecture; this can support up to 32 processors. After its failure however, AMD decided to license the Intel APIC Architecture for its AMD Athlon and later processors." The intent of the phrase "After its failure" is not clear. Was it Cyrix's failure (merger with National Semiconductor) or does it mean that the OpenPIC architecture initiative failed to take off?

AMD has removed the link to the OpenPIC specification mentioned above.

In any event, here are some fresher links:

1. See the list of IBM MPIC documents.
2. Freescale PIC Application Note
3. Section 1.3.10 of "P1020 QorIQ Integrated Processor Reference Manual"