Bit Select - Electronic Circuits Projects Diagrams Free

jbchrist · 5th June 2007, 02:56 PM

Ok....This should be an easy question, but I can't find the answer because I don't know what to look for.

I am writing a program for a PIC16f684, using the PIC C lite complier.

I have a 8 bit value stored and I want to take bit x and store it in a different variable.

How do I do that?

John

Pommie · 5th June 2007, 03:23 PM

I would guess,

NewVar = OldVar&(1<<X);

Would issolate the bit. (X = 0 to 7)

Mike.
Edit changed the operator to the bitwise one as PB pointed out.
Note to self, don't post at 2AM after a night out.

Papabravo · 5th June 2007, 04:47 PM

Using the && relational operator with an actual C compiler would be a pretty hard bug to find. You should use the bitwise & operator which will get you the intended result.

I would also highly recommend that you examine carefully the compiler's assembly language output to verify that it is doing what you want it to do.

jbchrist · 5th June 2007, 05:13 PM

Thanks! That worked beautifully!

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5th June 2007, 02:56 PM	(permalink)
jbchrist	Bit Select Ok....This should be an easy question, but I can't find the answer because I don't know what to look for. I am writing a program for a PIC16f684, using the PIC C lite complier. I have a 8 bit value stored and I want to take bit x and store it in a different variable. How do I do that? John

5th June 2007, 03:23 PM	(permalink)
Pommie	I would guess, NewVar = OldVar&(1<<X); Would issolate the bit. (X = 0 to 7) Mike. Edit changed the operator to the bitwise one as PB pointed out. Note to self, don't post at 2AM after a night out. Last edited by Pommie; 6th June 2007 at 01:32 AM.

5th June 2007, 04:47 PM	(permalink)
Papabravo	Using the && relational operator with an actual C compiler would be a pretty hard bug to find. You should use the bitwise & operator which will get you the intended result. I would also highly recommend that you examine carefully the compiler's assembly language output to verify that it is doing what you want it to do.

5th June 2007, 05:13 PM	(permalink)
jbchrist	Thanks! That worked beautifully!