HOW Long should an input be up for PIC to read it correctly?

[potpotpotpot]

How long should the input be up for PIC to read it correctly? The time, that the input must be there

 

[Nigel Goodwin]

How long should the input be up for PIC to read it correctly? The time, that the input must be there

Depends on your software, on how you write it, and on the clock speed used - but generally VERY short (few uS), assuming you write it that way?.

You would probably get more helpful answers though if you asked more specific questions?.

 

[potpotpotpot]

here's an example:

1 microcontrollers outputs 8 bits in its port, the other microcontroller should read this data output by the other microcontroller. Can the 2nd microcontroller read the output data of the first microcontroller even if the data only stays up for only about 1 to 5us??

 

[Nigel Goodwin]

here's an example:

1 microcontrollers outputs 8 bits in its port, the other microcontroller should read this data output by the other microcontroller. Can the 2nd microcontroller read the output data of the first microcontroller even if the data only stays up for only about 1 to 5us??

Yes, but that's a REALLY unreliable way to try and do it, if you really want to do parallel data transfer I suggest you look at the Centronics printer port, the handshake lines are there for a VERY good reason.

Do you have some specific reason for wanting to do parallel data transfer?, serial is much easier, and generally more than fast enough - and doesn't waste loads of I/O.

Some PIC's (like the 16F877) have a Parallel Slave Port, which may be helpful?.