Hi all.
I have some I/O timing questions.
I am using a PIC 16c84 4Mhz version using XT mode with 4mhz xtal and 15pf
caps.
I want to be able to monitor a pulse on a input pin (rb0) which only lasts
5 us.
For example with the following code:

loop
     btfss port_b, 00h    ; check rbo status
     goto  loop           ; rbo is low so loop again
     ............         ; rbo is high, take further actions

So my question is, is this possible?
Should I use interrupt?
Or better, use a faster pic version? (20mhz)
I don't have an oscillopscope but I have the data hand book 95/96

Another question...
Let's say I have an instruction which sets an ouptut high.
How long does this take in us/ns terms? Yes minmal one instruction cycle
but I expect that the rise to 5v of the output pin also takes some time..
So the total time will be 1 us + some rising time I expect.
I looked in the databook, couldn't find the information.

Last one...
What is the minimal input pulse duration I can monitor on a 20 mhz version?
So that when the input is high an action is taken and when it becomes low
again some other action is taken.

I hope someone can give me the details, thanks in advance.

D. Velthuis