I'm kind of new to this, but, here goes... "jtroxas" wrote in message news:fajt1n$7qg$1@sea.gmane.org... > How Fast can a typical PORT Pin of a PIC Micro Switch from Low to High or > vice versa... assuming the wire its connected to is short( maybe a few > inches) and connected to another PIC Micro PIn... Which device? Check the data sheet CLK and I/O timing waveforms to figure out how long it takes for the level switch (and to stabilize). > > i.e. if a Pin is Initially Low... and if I switch the PIN high and set it > to Input immediately.. and read it back in the next instruction.. Will I > be able to read the expected high level 1... You mentioned one pin tied to another pin. Depends on which pin it is tied to, how that pin is set up, and if there are other components. What is "immediately"? Every action in the PIC will take some number of clock cycles. Do you understand the concept of writing to the latch and reading from the pin? > > further more say its RA4 Pin with a Pull up resistor.. to turn it Low you > clear TRISA4.. then In the next Instruction I turn the PIN high by setting > TRISA4 to 1 making it an input.. and read it back immediately in the next > instruction.. Will you I be able to read the expected Input which is a > 1??? Again, it depends on pin RA4 is connected to and how that pin in set up. It could be that, once you make RA4 an input, the pull-up resistor will make it HIGH. If the pin it is going to is LOW, then RA4 would be LOW. > say if I was running the PIC at 40MHZ.. Depends on the device. Do the specifications indicate that it is designed to operate at 40MHz? > > At what speed should I be watchfull??? Good luck, Richard Seriani -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist