If-statement - Condition depending on output pin

Below I include simplified C code for a function 'read_ADC'.

RB0 is configured as output pin.

The function has to determine the state of RB0; then RB0 is cleared inside this function and other operations with ADC, etc. are implemented.
Then, RB0 must be restored, according to its original state.


Is it ok to check the state of RB0 (which is configued as outout pin) directly on the PORTB register?
The program runs correctly as I expected with the hardware. Do you see anything wrong/drawbacks with this solution? Of course I could update the variable RB0_state throughout the program, anywhere RB0 is changed; but this would require additional works and tests.

You don't say whether you are using an 18F or 16F series PIC, the answer may be a little different. It is perfectly fine to check port bits to see what the current output state is.

You can simplify your code to this though:

Thank you for your comments.

I am using a PIC16F. And of course I'll simplify the first lines as you have suggested.

OK, on a 16F the only thing you can do is read from the port itself (unlike the 18F, which has a data latch). You should also be aware of the read-modify-write problem just in case (see ).

As you rightly said earlier in the thread a good solution is to have a variable that keeps track of the current state of RB0 throughout the code.