PIC16F88 swaping bit status in PORTB

[ilmvmastm]

Hello every one!
I have a microcontroler PIC16F88. I want to make some simple
applications with it, but for some applications I need to swap the
value of one bit in one of two ports (PORTA or PORTB).
For example:
If PORTB bit 3 is set I want to reset it. And if PORTB bit 3 is reset
I want to set it.
In main idea i want to make logical NOT for bit 3 or antoher bit in
ports.
In programing language C this thing is :
PORTB,3 != PORTB,3
but I can't inplement this in my assembler program.

If someone understand my idea can you help me for this?
Thank you for your attention!

 

[Tim Wescott]

ilmvmastm wrote:

Hello every one!
I have a microcontroler PIC16F88. I want to make some simple
applications with it, but for some applications I need to swap the
value of one bit in one of two ports (PORTA or PORTB).
For example:
If PORTB bit 3 is set I want to reset it. And if PORTB bit 3 is reset
I want to set it.
In main idea i want to make logical NOT for bit 3 or antoher bit in
ports.
In programing language C this thing is :
PORTB,3 != PORTB,3

That's absolutely positively not C. It doesn't even match the
bastardized versions that I've seen implemented for small processors.

_Assuming_ the right bitfield definition for PORTB, you _could_ use
something like

PORTB.bits.BIT3 = ~PORTB.bits.BIT3; or
PORTB.bits.BIT3 = PORTB.bits.BIT3 ^ 1;

Both of these would work, even with a strictly ANSI-C compliant compiler.

but I can't inplement this in my assembler program.

If someone understand my idea can you help me for this?
Thank you for your attention!

But you need to do this byte-wise, which means that in C you'd do
something like

PORTB ^= 0x08; // exclusive-or bit 3

You'd do the same in assembler: read the port, xor with 08h, then write
it back to the port. How to do that in the 35 easy-to-learn
instructions that you get with a PIC is up to you.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html