Internal Interrupts

oracacle

Senior Member
While working on the software for the light box timer and thinking about polling variables to check if the desired time has been met, I thought that it would be easier to just poll a single variable.
So a flag bit are set in say B0 (bits 0 and 1) and the statement just looks for a single number in that variable - this led me to think about interrupts.
I have had a look through the commands list and there is no reference to internal interrupts from software. only inputs from the outside world.

Is this a limitation of the firmware? something that simply wasn't thought of? or considered and not used due to only being able to run one interrupt at a time?
 

oracacle

Senior Member
noticed while using a 20M2 with all the pins occupied.
its not really an issue more of an observation. It would have just made things a little more convenient in places

although as it happens I ma using the time variable on the 20M2 to count seconds.
 

oracacle

Senior Member
using pulsout, but having just tested as a matter of course it seems pretty spot of over 2 minutes by comparison to my watch.
The thing doesn't need to be 100% accurate and I cant see it being used for long periods of time so conflicts aren't going to cause much an issue.
 

inglewoodpete

Senior Member
noticed while using a 20M2 with all the pins occupied.
its not really an issue more of an observation. It would have just made things a little more convenient in places

although as it happens I ma using the time variable on the 20M2 to count seconds.
You may be able to swap your 20M2 for a 20X2. The chip itself in practically a pin-for-pin replacement, hardware wise. I would choose a 20X2 over a 20M2 almost every time due to its superior software (firmware) capabilities.
 

oracacle

Senior Member
I was tempted to make the swap, but as it happens the little light box timer works exactly as needed. and for keeping costs down as much as possible the M2 fitted the bill nicely.

The one I do find annoying about both packages is C.6 being input only, I suspect this is limitation with the underlying hardware so can't complain.
 

inglewoodpete

Senior Member
Yep. All PICs have to have a +Vpp pin for their (native) programming. So all PICAXEs have an input-only pin. This is sometimes a reset pin but, in other chips......
 
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