What is the "sign of life"?

Probably "heartbeat". It's an indicator that blinks or clacks or whatever to indicate that the processor is still operating.

Best regards, Spehro Pefhany

Are you designing another Mars rover? I'd suggest a large button on the outside, marked "DO NOT PRESS THIS BUTTON". If there are any Martians, they will inevitably press it, and you can light the LED.

But I think Spehro probably has the right end of the stick.

Paul Burke

Make sure to blink it from the main loop and not from a timer isr or something so that you are sure your main code is still executing.

--DF

Paul Burke =E5=AF=AB=E9=81=93=EF=BC=9A

Ya, hurry up to press what you have designed by yourself...

and

It is not so infrequent that embedded system has a HW reset button...

Boki.

Deefoo =E5=AF=AB=E9=81=93=EF=BC=9A

rd"

Thanks, but nobody think it maybe a battery indication?

Best regards, Boki.

If it is, you can use a blinking LED to indicate as much (e.g., certain blink rates indicate the state of battery charge or multiple blinks in a row tell you something or whatever); this provides significantly more objective information than just running an LED off a resistor connected to your mian battery and asking people to correlate brightness to battery charge. (Such an approach is really almost useless -- if you use, e.g., NiCad batteries, the discharge knee is so sharp that the LED would go from full brightness to nothing usually over the span of some minutes).

Definitely not.

If you wanted to be cute and the micro has an onboard dac, you could monitor the battery voltage and flash a bi-colour led green when the battery is good and red when the battery voltage is low.

Graham

Or (cheaper) change the duty cycle or frequency of a single LED depending on battery condition. I'm not sure where the DAC would come in. Some micros have a comparator and absolute reference so you wouldn't necessarily even need an ADC for go/no-go indication.

Best regards, Spehro Pefhany

the

red

Ooops. Typo. I did mean ADC but a comparator and reference would be fine too. Mind you, with the ADC you could change the led from green to red via yellow too if you liked !

Graham

monitor the

and red

Mind

you

You can do that with a ref and comparator too, just by adding a little ac or noise onto the reference line. Micros always have sources of that around.

NT

monitor the

and red

too. Mind

if you

Yes that would work too. What a source of bright ideas we are ! Boki, we expect this feature on your next product !

Graham