PMAC-PCI Hardware Reference
Software Setup 61
P1=0
WHILE (P1<360)
M10=$A000+P1 ; Sets address that M0 points to
M0=SIN(P1) ; Puts value in register that M0 points to
P1=P1+1
ENDWHILE
Note that this technique is not possible with L-variables in compiled PLCs (but it is possible with M-
variables in compiled PLCs).
Physically, the Option 16 memory is a 16k x 24 bank of battery-backed static RAM. It maps into the
PMAC and PMAC2 at addresses $A000 to $BFFF, on both the X and Y data buses, an 8k x 48 block of
address space. Addresses Y:$BC00 to Y:$BFFF are “double-mapped” with the main flash-backed RAM
for the M-variable definitions, and should not be used for user parameter storage.
Any value written into the Option 16 memory will automatically be retained through a power-down or
reset; no SAVE operation is required. The power draw on the battery is low enough that battery life will
typically be limited only by the quoted 10-year life of the battery.
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