ColdFire/68K Microcontrollers and Processorsのトピック52252 powerfail detection

52252 powerfail detection

LPs1978 — Tue, 24 Mar 2009 17:47:29 GMT

Hi all,

I'm designing a new low cost application and I need to save some data in a falsh sector when power fails.

I have questions:

it's ok to use the LVD interrupt to start the flash save procedure? What is the VDD minimum that cause the interrupt (threshold)?
This interrut can leave me time enough to write a flash sector?

The not so low cost solution is to have an external circuit connected to an IRQ pin that allow me to define the threshold.

Are these available solutions or someone had some different ideas?

Thaks in advvance.

Message Edited by LPs1978 on 2009-03-24 10:48 AM

Re: 52252 powerfail detection

mjbcswitzerland — Tue, 24 Mar 2009 20:21:33 GMT

This topic is being discussed here:

http://www.utasker.com/forum/index.php?topic=549.0

Maybe that will help you.

Regards

Mark

www.uTasker.com

Message Edited by mjbcswitzerland on 2009-03-24 02:21 PM

Re: 52252 powerfail detection

RichTestardi — Tue, 24 Mar 2009 20:33:19 GMT

I also would be concerned with the supply voltage being so far out of spec when the lvd interrupt occurs to try and get any meaningful work done (even if the supply came back!), much less manipulate flash...

What we have done in the past is set up a resistor divider on the *pre* regulated supply voltage (dividing it to within spec of the a/d converter), and then we can watch as it drops below the regulators drop-out voltage, and thereby get our meaningful work done before the supply voltage is out of spec.

-- Rich