INC is a short (2 Bytes) and fast (12 clocks) way to manipulate the DPS bit in the
AUXR1 SFR. However, note that the INC instruction does not directly force the DPS bit
to a particular state, but simply toggles it. In simple routines, such as the block move
example, only the fact that DPS is toggled in the proper sequence matters, not its actual
value. In other words, the block move routine works the same whether DPS is '0' or '1'
on entry. Observe that without the last instruction (INC AUXR1), the routine will exit with
DPS in the opposite state.
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AT89C51RB2/RC2
4180C–8051–12/03
ATMEL [ ATMEL ]
