digital input question...

[Kevin Karan]

Alright, feeling stupid. I know that the digial inputs give wierd junk since they are char variables. So what bit do I read and how. Thanks

[Ryan M.]

?

If you just want to tell if it is HIGH or LOW, you can do a check if it is 1 or 0. If for some reason you have to actually access the bits, experiment. I'm not sure if the chip is big- or little-endie.

[Kevin Karan]

The digital inputs are given as a char, but only one of the bits are actualy accurate, but I dont know what one. I know there is a post on this forum about it, but I cannot find it. AND, i cant remember how to get the value of a specific bit under c, is it var:1 or is it var&1

[KenWittlief]

the digital inputs on the RC are already defined in the code for you - they can only have a value of 1 or 0

all you need to do is look at the right variable

rc_dig_in01 is digital input one on the RC

so you can do stuff like

if (rc_dig_in01 ==1) variableXYZ=123;

if (rc_dig_in14 ==0) variableQRS=127;

what else do you want to do with them?

[Ryan M.]

Originally Posted by KenWittlief

the digital inputs on the RC are already defined in the code for you - they can only have a value of 1 or 0

all you need to do is look at the right variable

rc_dig_in01 is digital input one on the RC

so you can do stuff like

if (rc_dig_in01 ==1) variableXYZ=123;

if (rc_dig_in14 ==0) variableQRS=127;

what else do you want to do with them?

Looking back at my old post, I meant that, but I see how you didn't get it. You can't access a certain bit in a variable in an actual function. The first syntax you stecified can be used in a struct like this:

stuct bitVariable
{
int bit0:1;
int bit1:1;
int bit2:1;
int bit3:1;
// ...
};

Basically, tht gives each of the variables inside it one bit of the int. (at least, I think I got that right... ) Like Ken said though, you can just read the variable directly.

[10intheCrunch]

I'm pretty sure you can, if they are set up in a struct together. Say:

if(SomeStructbits.bit0) blah;

If you only want to see the first bit of any variable, though, use modulus.

if(someVar % 2) morestufftodo;

If you aren't familiar with modulus, it gives the remainder of dividing by the number you mod by, ie modding by 2 gives you one or zero depending on if the number is even or odd (or rather, if the first bit is 1 or 0).

Good luck.

[Astronouth7303]

If you want the 2 least significant bits, wouldn't it make more sense to do:

if(someVar & 3) evenmorestufftodo;

?

[Joe Ross]

Originally Posted by Astronouth7303

If you want the 2 least significant bits, wouldn't it make more sense to do:

if(someVar & 3) evenmorestufftodo;

?

That is what I would do, becasue the modulus operator is often slow (of course depending on the microprocessor). I haven't checked on the PIC, but if you ever want to move your code to a different platform, it's best to write for the lowest common denominator.

Sorry for bringing this thread up from the dead.

[Kevin Karan]

sorry for not being at all active on my threads lately... at buckeye I came up with something that worked well, though I cant remember it...

[Astronouth7303]

I HATE that!