Rev. 1.0, 02/00, page 46 of 1141
2.6.5
Notes on Use of Bit-Manipulation Instructions
The BSET, BCLR, BNOT, BST, and BIST instructions read a byte of data, carry out bit
manipulation, then write back the byte of data. Caution is therefore required when using these
instructions on a register containing write-only bits, or a port.
The BCLR instruction can be used to clear internal I/O register flags to 0. In this case, the
relevant flag need not be read beforehand if it is clear that it has been set to 1 in an interrupt
handling routine, etc.