Ex_2 use DMA prime cache (ex_1 merge)

[Defragster]

Merged Ex_1 edits dropping DMA into Ex_2

Updated 't' _isr Busy loop to use DMA array - running faster using ref table allows more _isr's sec and also using DMA buffer - some part of 32KB with each _isr to confirm it doesn't conflict/confuse and camera driver code using that memory.

No reason this Ex_2 can't replace Ex_1 as it does nothing ( except idle code ) unless the 't' is activated for timing. Generating _isr() busy work and a flurry of interrupts to do it. loading the CPU rather than just an empty loop().

Adjusting priRestart to smaller or larger PRIME # ( several listed in //comment ) will vary the completion time of the _isr allowing more or less to complete before the next timer tick.

Adjusting PrPS is the freq of the _isr()'s desired

Adjusting tableSize to 1 eliminates the DMA usage for cache of lower prime factors to test

Opps : just saw I did not add DMAMEM to that - running from RAM1 or DMAMEM shows same behavior, will edit that in as comment option after creating PR