brown out resets

[robertpeach]

hey again guys, ive managed to create my program eventually.. the pic is basically the controller of the rectifier controller of a wind turbine... :P everything works nice and smooth and how id like it to.

however there is one last thing i want to implement. im trying to display total kilowatt hours on the LCD, however obviously when the wind dies then the pic has no power and therefore turns off... but when the wind revives the pic restarts due to the brown out reset.

however when the brown out resets occurs i will have lost all temporary data in the ram. i was wondering if there was a way to use some form of brown out interupt to quickly save the data of "total energy accumulated" before the voltage goes so low that the pic turns off. and then when the reset occurs the energy accumulated is then taken from flash and carried on counting the energy?

or if there is another way of doing this effectively

thanks :P

[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