Xiaofan Chen wrote: > On Wed, Nov 5, 2008 at 10:13 PM, Walter Banks wrote: > > ISO61131 based process control applications for example are likely to > > map on the enhanced mid range cores quite well. > > I am working for a PLC company. But sorry I have no idea > what do you mean by this sentence. ISO61131 formally defines IL (Instruction language) ST (structure language) and LD (Ladder) it ties them together and defines the relationship between them. Sequential Function Chart (SFC) and Function Block Diagram (FBD) define how the pieces are assembled in an application. Two very interesting points. Function Block Diagrams are an approach to build a large programming system that is processor element independent. From a programmers point of view FBD's can be implemented in a single or multiple processors and the controlled system doesn't care. My second point is the implementation can be (probably should be) event driven and that maps well on the enhanced mid range parts. FBD's have been extended and enhanced in some other ISO documents. FDB's are a reasonably well defined way to accomplish parallel programming independent of the number of underlying processors. The enhanced mid range parts could well become a FDB or third party supplied FDB to be incorporated into a larger system. Regards -- Walter Banks Byte Craft Limited http://www.bytecraft.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist