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[on:]

Hi,
    I am trying to access a port through a variable as in -

Code:

thePort = PORTB;

thePort ^= 255;

 

    Whatever I do I cannot get this to work inside a library - I am sure its something daft but I need another pair of eyes to see it

Thanks

Duane B

[Reply #1 on:]

Hi,

Try this...

Code:

static uint8_t volatile * thePort;

thePort = & PORTB;

*thePort ^= 255;

Edit: Forgot the ampersand.

[Reply #2 on:]

your code makes a copy of the value in the port, you should write it back.

thePort = PORTB;
thePort ^= 255;
PORTB = thePort;

[Reply #3 on:]

Hi,
   Thanks all, mystery solved, it was the forgotten ampersand.

Thanks

Duane B.

[Reply #4 on:]

Easy:

Code:

#define thePort PORTB

thePort ^= 255;

[Reply #5 on:]

Easy, also pointless.

Duane B

[Reply #6 on:]

Code:

volatile uint8_t& thePort = PORTB;
thePort ^= 0x08