Active low pin?

[flemse]

Hi

How to make active low assigment at a pin?

//At this assigment you must remember whitch is active low or not
#define led_r PIN_A4 //output is active low !
#define led_g PIN_A5 //output is active low !

--

//why cant i do this? making the pin as active low
#define led_r !PIN_A4 //output is active low !

//Flemming

[Ttelmah]

The definition 'PIN_A4', is not the actual pin, but a numeric value, to _address_ the pin. Inverting this, will simply result in addressing the wrong location.
The answer, if you are using -ve logic, is to define your own versions of the pin access functions, so something like:

[Ken Johnson]

Or, something like this:

#define LEDRed(on) output_bit (PIN_B4, on) // Active Hi

#define LEDRed(on) output_bit (PIN_B4, !on) // Active Lo

Then, LEDRed(0) turns it off; LEDRed(1) turns it on

Ken

[flemse]

Hi

Thanks a lot thats help:-)

Flemming