On Sat, 10 Jan 2004 14:21:00 +0100, Jan-Erik Svderholm XA (TN/PAC)
wrote:

>Hi.
>I don't remember what PIC you are using, but...
>
>On the 18-series you can write to the LATx regsiters
>instead of the PORTx registers. This should avoid some
>of these problems. I'd guess that what you are writing
>about is the read-before-write problems when using
>the bit handling instructions on port registers, where
>the read part will read whatever the pin is driven to by
>some external source, right ?
>
>The LATx regs in the 18-series solves this problem.
>

On the 16-series devices, so does avoiding the use of bit set/clear
operations on ports by rolling your own read-modify-write operation.
Reading the whole port in, modifying W as you need to, and then
writing the whole thing back works well in situations like this. :=)

While the bsf and bsf opcodes certainly *can* be used on ports,
they're not the only (nor sometimes the best) way to change port bits.


Regards, Bob

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