brown out resets

[mackrackit]

OK, lets back up and tell how you are powering the PIC. Voltage and voltage source(source is from wind machine) but it has to be brought down/up to PIC levels.

If you are still on the same PIC and project I think you are running at 20Mhz, so I will assume you are getting around 5 volts from some place. ????

[robertpeach]

well basically we have got the analogue high voltage part of the circuit which is converted to a 5v voltage for the CAP inputs and the ADC measuring voltages.

we also have a DC 12v supply from another part of the power electronics which i attach to a 12DC to 5DC converter... this is wheree i get the voltage to power the pic

[mackrackit]

OK, that gives you plenty to work with. You should be able to adapt the schematic in the thread I linked you to.

What we are basically doing is monitoring the 12 volt in this case. An ADC could be used but you will have to keep checking it in your code. If you use the interrupt on change then it all happens for you...

Either way, the trick is having large enough caps to run the PIC long enough to write the data to eeprom. When the voltage coming to the PIC or the power supply drops beyond a certain point your software will jump to a SAVE/SHUT DOWN routine.

The problem I see happening with you setup is the voltage drops enough to go to the SAVE routine then comes back up before the PIC actually stops from lack of voltage.

[robertpeach]

how do these interupts on change work? is this the DT instant interupt stuff? are there any specific brown out reset interupts?

edit: actually just found it in data sheet, looking through it now

[mackrackit]

You can use DTs stuff for this but regular interrupts should be fast enough.

[robertpeach]

ok thanks, ill just use normal interupts! im gonna look around and try and make some code to use interupts

[robertpeach]

ok ive made my code, probably got some errors in, however thats not the problem. ive been thinking about this whole trouble with if the voltage is idling on a point lower than my low voltage detection level but not low enough that it causes a reset... problem is.. if it gets too that point my program starts looping because the interupt keeps getting set off by the low voltage.

i was thinking since when the wind turbine actually gets slow enough that the voltage is about 2-3 volts, its not actually giving out any power (if it does then its completely negligible). so when i get to a low point can i just turn off the pic? and get it too restart when the power gets higher?