Forums

LPC2106 Reset Time Duration

Started by europaphi September 9, 2008
Hello,

I'm having an issue with the LPC2106, whereby the time it takes from
power up to execution start of main() is ~25ms. This is too long for my
application requirements.

I'm using the IAR compiler for this project and have traced this issue
all the way back to the invocation of cstartup.

Is it possible that the LPC2106 bootloader (v1.52) is somehow
temporarily hanging up the power up sequence? From the literature, it
appears the bootload pin is sampled for a maximum of a few milli-
seconds by the bootloader.

I've checked the bootloader pin and it is pulled high for the duration
of power up, so I would expect that after a few milliseconds, cstartup
would be invoked.

Thanks in advance for any help you can provide.

An Engineer's Guide to the LPC2100 Series

europaphi wrote:
> Hello,
>
> I'm having an issue with the LPC2106, whereby the time it takes from
> power up to execution start of main() is ~25ms. This is too long for my
> application requirements.
>
> I'm using the IAR compiler for this project and have traced this issue
> all the way back to the invocation of cstartup.
>
> Is it possible that the LPC2106 bootloader (v1.52) is somehow
> temporarily hanging up the power up sequence? From the literature, it
> appears the bootload pin is sampled for a maximum of a few milli-
> seconds by the bootloader.
>
> I've checked the bootloader pin and it is pulled high for the duration
> of power up, so I would expect that after a few milliseconds, cstartup
> would be invoked.
>
> Thanks in advance for any help you can provide.
>
If memory serves me correctly the power up sequence time for the
LPC2106 is 80ms. This is hardware dependent.

regards,
Charles

--- In l..., "Charles R. Grenz"

Charles,

Thanks for the response.

I've looked everywhere for documentation explaining or specifying the
time it takes the LPC2106 to perform a hard (or soft - via watchdog)
reset with no luck.

>From what I've gathered, if the bootloader does not detect the
bootload pin as low, it immediately hands execution to the user's
FLASH application. This should take a few milliseconds at most.

Does the LPC2106 REALLY take 10s of milliseconds to come out of
RESET? From what I've read, the PLL does take some time (4096
cycles?) to stabilize but I'm using a 14.725MHZ external oscillator.

This is not making any sense.

Any thoughts?

wrote:
>
> europaphi wrote:
> > Hello,
> >
> > I'm having an issue with the LPC2106, whereby the time it takes
from
> > power up to execution start of main() is ~25ms. This is too long
for my
> > application requirements.
> >
> > I'm using the IAR compiler for this project and have traced this
issue
> > all the way back to the invocation of cstartup.
> >
> > Is it possible that the LPC2106 bootloader (v1.52) is somehow
> > temporarily hanging up the power up sequence? From the
literature, it
> > appears the bootload pin is sampled for a maximum of a few milli-
> > seconds by the bootloader.
> >
> > I've checked the bootloader pin and it is pulled high for the
duration
> > of power up, so I would expect that after a few milliseconds,
cstartup
> > would be invoked.
> >
> > Thanks in advance for any help you can provide.
> >
> If memory serves me correctly the power up sequence time for
the
> LPC2106 is 80ms. This is hardware dependent.
>
> regards,
> Charles
>

europaphi wrote:
>
> --- In lpc2000@yahoogroups .com ,
> "Charles R. Grenz"
>
> Charles,
>
> Thanks for the response.
>
> I've looked everywhere for documentation explaining or specifying the
> time it takes the LPC2106 to perform a hard (or soft - via watchdog)
> reset with no luck.
>
> >From what I've gathered, if the bootloader does not detect the
> bootload pin as low, it immediately hands execution to the user's
> FLASH application. This should take a few milliseconds at most.
>
> Does the LPC2106 REALLY take 10s of milliseconds to come out of
> RESET? From what I've read, the PLL does take some time (4096
> cycles?) to stabilize but I'm using a 14.725MHZ external oscillator.
>
> This is not making any sense.
>
> Any thoughts?
>

Yes, sometimes you have to go back to the vendor to get certain
questions answered. I would contact your local NXP (Philips) Sales
Representative and tell them what you need. These people are either
listed on the NXP website, generally under 'sales', or contact the
distributor that you purchased the chips from.

There are Field Engineers who answer these types of questions. And,
they work for the chip vendor.

TomW

--
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net http://cyberiansoftware.com http://openzipit.org
"Windows? No thanks, I have work to do..."
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