Question about scope and recycling of vars

[Coccoliso]

If you have these needs you should diversify processes in order to achieve maximum performance.
I had a similar problem and, like you said I separate the display part from the acquisition part but I used 2 PIC24 in CAN bus.
Since it is based on messages with identifier sent from one side and those who receive them reads only those that can process.With only a 3-wire bus you can connect more PIC and for a few bytes sent is fast and does not require overload because the CAN is managed in its own right and buffers.

[Timbo]

Sounds good but a little overkill for my needs. The can bus though is really going to be a boon for other jobs.

[Coccoliso]

Besides the 24HJ128GP502 (standard MPU mounted on Firewing 24) there are several PIC18 28-pin MPU (18F2682 or 18F2685) and 40-pin MPU (18F4682 or 18F4685) and do not require a lot of effort in the development but in Firewing you have to compile with Swordfish's toolsuite.