yep i forgot for moment about interrupts , the bottom line is what ever speed you can run the EMB , then thats the top speed of the whole pic from that point.


i might say adding EMB is not something you really want to do, unless you really really had to ,

for starters the chip is a 80 pin chip , its costing about $6 , for under 50 units plus then 16bit flash at 90ns , at about $2 each , plus interface glue logic , and add to opcb design , manufacture etc etc

also if you needed some of those 80 pins for microprossors i/o use and they are also used for the EMB interface some addtional interfacing is also required.

its clear you will reduce your speed down of the pic to 25mhz , perhaps 32mhz if your lucky ,( waiting on MIcrochip responce for 16 bit EMB spec )

so the 128k limit of 8 bits chips , from the options covered here in this thread , you are far far better to

A. Do Not Use PBP -
if you ever suspect or likely ever to expand a project and there a chance you need more that 128k of internal code space for the project, and want to use the chips 64mhz speed , . then drop any plans to use pbp from the start ,
as the there are very few ways you can go forward , and for the most part your project will be higher cost / effort than choosing another platform , even if you know pbp well ,
there is no upward way forward and there is not likely to be so for sometime.

B. if no other choice and you find your self at the 128k limit and you have used PBP , then you seem to have 2 options

1. You poor sole - its time to consider the longer road and learn C coding in the end it more transportable , port your code to another plateform and never look back but loose a lot of time on the project your on now

2. stick with PBP but add 2 or 3 CPUs , split the fuctions/ supported hardware over the cpus , however your not ever going to get a double / triple of extra space
the overheads are large depeding on the fuctions / interface code overheads on each cpu and that maintaing more cpu's coding make for lot more work , updating etc , your only stalling the above options but it may be enough
to get you over the line, and time to reconsider ever going down the PBP again for project that has the chance to get past 128k.


as said this sucks some days

will update when microchip gives a meaning full reply for Fmax on the EMB at 16bit interface
cheers sheldon