PIC16C8X Datasheet, PDF (14/117 Pages) Microchip Technology – 8 BIT CMOS EEPROM MICROCONTROLLERS

PIC16C8X
4.2.2.1 STATUS REGISTER
The STATUS register contains the arithmetic status of
the ALU, the RESET status and the bank select bit for
data memory.
As with any register, the STATUS register can be the
destination for any instruction. If the STATUS register is
the destination for an instruction that affects the Z, DC
or C bits, then the write to these three bits is disabled.
These bits are set or cleared according to device logic.
Furthermore, the TO and PD bits are not writable.
Therefore, the result of an instruction with the STATUS
register as destination may be different than intended.
For example, CLRF STATUS will clear the upper-three
bits and set the Z bit. This leaves the STATUS register
as 000u u1uu (where u = unchanged).
Only the BCF, BSF, SWAPF and MOVWF instructions
should be used to alter the STATUS register (Table 9-2)
because these instructions do not affect any status bit.
Note 1: The IRP and RP1 bits (STATUS<7:6>) are
not used by the PIC16C8X and should be
programmed as cleared. Use of these bits
as general purpose R/W bits is NOT
recommended, since this may affect
upward compatibility with future products.
Note 2: The C and DC bits operate as a borrow
and digit borrow out bit, respectively, in
subtraction. See the SUBLW and SUBWF
instructions for examples.
Note 3: When the STATUS register is the
destination for an instruction that affects
the Z, DC or C bits, then the write to these
three bits is disabled. The specified bit(s)
will be updated according to device logic.
DS30081F-page 14
© 1995 Microchip Technology Inc.