brown out resets

[Jerson]

What I'd recommend is to use an early warning signal. The raw voltage input to the 5V regulator would be a good point to monitor the power. Use this voltage to signal a power failing and if this is set properly, you can get sufficient time to put your counter to EEPROM. Your 5V should be bypassed sufficiently to allow the write to complete.

[mackrackit]

This might give you an idea or two
http://www.picbasic.co.uk/forum/showthread.php?t=11567

[robertpeach]

thanks guys, unforuantely i didnt really understand much of what was going on in that thread mack! it seems a bit advanced for me..

i havnt actually got a voltage regulator, or ever used one... so they take the input and then give me an output voltage which i can send to the pic? how would i measure the output voltage, just use an ADC port?

[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