Hardware Reset on Startup
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Posts: 46,084
Hi, all.
I need to assert a reset to a BS-2 on powerup. I must be done from
hardware as there's no memory left for a wait loop in memory.
The normal way to to this is to use an RC circuit connected to the
reset pin which stays "lo" for a second or so, but this would violate
the Stamp's "don't drive the reset pin high" rule.
Any suggestions?
TIA
John
I need to assert a reset to a BS-2 on powerup. I must be done from
hardware as there's no memory left for a wait loop in memory.
The normal way to to this is to use an RC circuit connected to the
reset pin which stays "lo" for a second or so, but this would violate
the Stamp's "don't drive the reset pin high" rule.
Any suggestions?
TIA
John
Comments
kb3cny@a... writes:
Hi, all.
I need to assert a reset to a BS-2 on powerup. I must be done from
hardware as there's no memory left for a wait loop in memory.
The normal way to to this is to use an RC circuit connected to the
reset pin which stays "lo" for a second or so, but this would violate
the Stamp's "don't drive the reset pin high" rule.
Any suggestions?
TIA
John
=======================================
John,
This idea has a large pin count......but you could use an op amp comparitor
that has an open collector output tied to the reset pin.
You could then set the - input at 2.5 volts with a voltage divider and have
an RC drive the + input.
Ken
[noparse][[/noparse]Non-text portions of this message have been removed]
> kb3cny@a... writes:
> Hi, all.
> I need to assert a reset to a BS-2 on powerup. I must be done from
> hardware as there's no memory left for a wait loop in memory.
>
> The normal way to to this is to use an RC circuit connected to the
> reset pin which stays "lo" for a second or so, but this would violate
> the Stamp's "don't drive the reset pin high" rule.
>
> Any suggestions?
>
> TIA
> John
>
> =======================================
> John,
> This idea has a large pin count......but you could use an op amp
comparitor
> that has an open collector output tied to the reset pin.
>
> You could then set the - input at 2.5 volts with a voltage divider and
have
> an RC drive the + input.
>
> Ken
______________
Thanks, Ken,
That sounds like a winner.
Don't mind the extra pin count either. Seems like the Stamp
is very quick in starting, before the rest of my circuit stabilizes. I'll
post
the results in a day or so.
John