Arduino Specific Interrupt Question for CHANGE analog or digital?

The explanation of interrupt so you don't have to look is as follows interrupt: the number of the interrupt (int)

function: the function to call when the interrupt occurs; this function must take no parameters and return nothing. This function is sometimes referred to as an interrupt service routine.

mode defines when the interrupt should be triggered. Four contstants are predefined as valid values:

LOW to trigger the interrupt whenever the pin is low, CHANGE to trigger the interrupt whenever the pin changes value RISING to trigger when the pin goes from low to high, FALLING for when the pin goes from high to low.

The question is for CHANGE. It says whenever the pin changes values but this is vague. For my 1284p the interrupt is on the TX1 pin which is digital. This should mean it interrupts whenever there is a rising or falling edge. I have a qrd1114 encoder counter that gives an analog output to the INT1 input pin. So the final question is this. It ignores analog because it does not have the capability of a ADC and only changes when the pin drops over the high or low threshold for digital right? ... Or does this pin have a ADC?

as far as I know the pin does not have an ADC and it will trigger on thresholds... disclaimer: no 1284 expert what does the datasheet say on this?

The datasheet gives a block diagram. I'm just nit picking on the website's explanation. I'll know in a second its faster to test it since everything is prototyped. I'll be back soon.

Datasheet says you can create an Interrupt from the Analog Comparator- maybe that's the solution you need. See section 12.

Is this the data sheet for your encoder counter?

http://www.fairchildsemi.com/ds/QR/QRD1113.pdf

Mark

If it is, that would create a fine digital output. Use the input pin with internal pullup connected to pin 1, pin 2 to Gnd. When current flows thru the LED, the transistor turns on & pulls the pin low.

SouthernBinary: The question is for CHANGE. It says whenever the pin changes values but this is vague. For my 1284p the interrupt is on the TX1 pin which is digital. This should mean it interrupts whenever there is a rising or falling edge.

I don't see a TX1 pin on the datasheet. Do you mean TXD0 (pin 15 on the chip)? Or TXD1 (pin 17 on the chip) which is also INT1?

That is not listed as an an ADC input and thus the interrupt would trigger when the voltage level rises above or below the level required for a digital transition.

I'm just nit picking on the website's explanation

Which website? Which explanation?

It says whenever the pin changes values but this is vague.

I don't recall any of the external interrupts (to which the attachInterrupt documentation refers) being analog inputs. Therefore the explanation is not vague. Its value is either HIGH or LOW.