Microcontrollers with internal oscillators have a calibration word programmed into them at the factory, in the last address location. I would like to know a couple things regarding this topic.
Under what circumstances can you accidentally erase the calibration and have to recalibrate? If you get a shiny new PIC and drop a program into it that doesn't have the calibration value in it, does it overwrite the factory setting? In other words, should the first thing I do when I get a new PIC is pop it in the programmer and "read" it so I can see what the factory setting is, and make a note of it to ensure I don't lose it?
It seems I've gone and erased my calibration value, and it also seems that each value is pretty much unique to each PIC that is manufactured, so there's not a "standard value" you can just drop in the thing. Now my PIC appears to be pretty much useless for any kind of semi-accurate timing, let alone accurate timing.
Thanks.
Under what circumstances can you accidentally erase the calibration and have to recalibrate? If you get a shiny new PIC and drop a program into it that doesn't have the calibration value in it, does it overwrite the factory setting? In other words, should the first thing I do when I get a new PIC is pop it in the programmer and "read" it so I can see what the factory setting is, and make a note of it to ensure I don't lose it?
It seems I've gone and erased my calibration value, and it also seems that each value is pretty much unique to each PIC that is manufactured, so there's not a "standard value" you can just drop in the thing. Now my PIC appears to be pretty much useless for any kind of semi-accurate timing, let alone accurate timing.
Thanks.