[time-nuts] One sure way to kill your FE-5680A or FE-5650A
Bob Camp
kb8tq at n1k.org
Thu Jun 9 11:42:34 UTC 2016
Hi
Based on the number of different ways there seem to be to corrupt the operating software
in the FE Rb’s …. they seem to have a unique problem. There are a *lot* of devices
using the same basic parts that don’t turn into a brick when this or that happens.
Bob
> On Jun 9, 2016, at 4:31 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
>
>
>> The ATTinys have brownout detectors in them that’s supposed to keep them
>> from going bonkers during undervolt periods.
>
> Startup and/or brownout has long been a nasty problem area for digital
> designers.
>
> In the old old days, there was typically a R/C delay on the reset pin to a
> CPU. That screwed up when the power supply ramped up slowly enough. Most
> old timers have that merit badge.
>
> Modern CPU chips often have specs like power must be OK for 200 ms before
> releasing Reset. Anything like that will have at least one corresponding
> power monitor chip with several supply voltage inputs and the appropriate
> delay.
>
> The brownout side gets ugly when you look at the tolerances. The tolerance
> on the power monitor subtracts from the power supply tolerances.
>
> There is another worm in the can. How long does it take for your oscillator
> to get going?
>
>
>
> --
> These are my opinions. I hate spam.
>
>
>
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