Stanley,

If that is the complete program, then P2 will be zero, so moving a zero from p2 to p0 will not show up.

try this instead:-


    ORG    0000H
    JMP    MAIN
    ORG    0050H

MAIN:
    CPL    20H.1
    JMP    MAIN
END


This should flip the p0.1 high an low, each time through (very fast!)

Chris.