Long time lurker here... my first post.

There are many possible reasons as other have pointed out. One that has not been mentioned yet, it is possible for a JTAG device connected to your board to cause apparently random resets. I had a Keil ULINK2 reset an LPC2102 at random, I was lucky that it only took me days and not weeks to figure this one out.

It may be that the boards not showing this issue may not have a JTAG device connected.

Also for intermittent problems occurring on some boards and not others, watch out for the MAM bug detailed in the Errata and discussed in several threads on these forums.

Hope this helps,
Mike

-----Original Message-----
From: l... [mailto:l...] On Behalf Of Manuel Kpen
Sent: Thursday, June 18, 2009 4:15 AM
To: l...
Subject: Re: [lpc2000] Final LPC Issue: External Reset happens randomly on LPC2101

Hello!

I wouldn't be so sure that it is a hardware reset. Your application may
have some bug, so that it starts over (e.g. jumps to a faulty pointer).
In that case, it wouldn't be a "real" reset, and the reset reason
registers wouldn't change, so they may still carry the reason from first
start of the firmware,
which will be hardware reset if you use some kind of reset logic on the
board.

Did you clear the RSIR register (by writing 7 to it) in your startup
code, of cause after making a copy for later investigation?
That way you will get the real reset cause if there is one...

Best regards,
Manuel Kpen
p...@yahoo.co.in wrote:

Hi,
I am working on LPC2101.LPC is resetting randomly.
I found the reset reason using RSIR registers.It shows external
reset(Value is 2). From user guide,assertion of reset pin makes LPC to
reset.

1) What are the conditions in LPC2101 to assert reset line automatically?
2) How to debug this in Software level as well as Hardware level?
3) If anybody faced this issue in already,
Please share your knowledge about how did u debug and fixed this issue?
4) Is this related to power or any other pin interference to reset pin?

I haven't more experience in LPC.Any experience persons,help me??

Additional Information:
This reset issue happens randomly and some board i couldn't see this issue

--

-

_/_/_/_/ Manuel Kpen
_/_/_/_/ Dipl.-Ing.
_/_/_/_/ m...@esd-electronics.com

_/_/_/ _/_/_/_/_/_/_/ esd electronic system design gmbh
_/ _/ _/ _/ Vahrenwalder Str. 207
_/ _/ _/_/_/ _/ _/ D-30165 Hannover - GERMANY
_/ _/ _/ _/ Phone: +49-511-37298-0
_/_/_/_/_/_/_/ _/_/_/ Fax: +49-511-37298-68

-
Geschtsfrer: Klaus Detering, Dr. Werner Schulze
Amtsgericht Hannover HRB 51373 - VAT-ID DE 115672832
-
Bitte besuchen Sie uns im Internet unter http://www.esd.eu

An Engineer's Guide to the LPC2100 Series

Hello!

I wouldn't be so sure that it is a hardware reset. Your application may
have some bug, so that it starts over (e.g. jumps to a faulty pointer).
In that case, it wouldn't be a "real" reset, and the reset reason
registers wouldn't change, so they may still carry the reason from first
start of the firmware,
which will be hardware reset if you use some kind of reset logic on the
board.

Did you clear the RSIR register (by writing 7 to it) in your startup
code, of cause after making a copy for later investigation?
That way you will get the real reset cause if there is one...

Best regards,
Manuel Kpen
p...@yahoo.co.in wrote:

Hi,
I am working on LPC2101.LPC is resetting randomly.
I found the reset reason using RSIR registers.It shows external
reset(Value is 2). From user guide,assertion of reset pin makes LPC to
reset.

1) What are the conditions in LPC2101 to assert reset line automatically?
2) How to debug this in Software level as well as Hardware level?
3) If anybody faced this issue in already,
Please share your knowledge about how did u debug and fixed this issue?
4) Is this related to power or any other pin interference to reset pin?

I haven't more experience in LPC.Any experience persons,help me??

Additional Information:
This reset issue happens randomly and some board i couldn't see this issue

--

-

_/_/_/_/ Manuel Kpen
_/_/_/_/ Dipl.-Ing.
_/_/_/_/ m...@esd-electronics.com

_/_/_/ _/_/_/_/_/_/_/ esd electronic system design gmbh
_/ _/ _/ _/ Vahrenwalder Str. 207
_/ _/ _/_/_/ _/ _/ D-30165 Hannover - GERMANY
_/ _/ _/ _/ Phone: +49-511-37298-0
_/_/_/_/_/_/_/ _/_/_/ Fax: +49-511-37298-68

-
Geschtsfrer: Klaus Detering, Dr. Werner Schulze
Amtsgericht Hannover HRB 51373 - VAT-ID DE 115672832
-
Bitte besuchen Sie uns im Internet unter http://www.esd.eu

--- In l..., "bobtransformer" wrote:
>
> --- In l..., prabuisin@ wrote:
> >
> > Hi,
> > I am working on LPC2101.LPC is resetting randomly.
> > I found the reset reason using RSIR registers.It shows external reset(Value is 2). From user guide,assertion of reset pin makes LPC to reset.
>
> First thing I would look at is your power supply lines, especially if the RESET line is just pulled up to +3.3 Volts.
>
> Also, do you have a small cap (~ 0.1 microfarad) across the RESET line and also one or two bypass caps across the +3.3V to GND lines ?
>
> I'd look at my 3.3V with a scope. I bet you find it dropping momentarily...
>
> Keep us posted.
>
> boB

I almost forgot (actually, I did forget)...

If the power supply lines and reset line doesn't droop during operation to cause the problem, look at ALL of the other I/O lines.

If there is too much noise, bringing those lines too high or too low in voltage, it could cause problems as well.
That has a lot to do with the environment of the unit as someone else mentioned. I've had problems in that regard before in a noisy environment... Especially switching power supply type applications.
boB

>
> >
> > 1) What are the conditions in LPC2101 to assert reset line automatically?
> > 2) How to debug this in Software level as well as Hardware level?
> > 3) If anybody faced this issue in already,
> > Please share your knowledge about how did u debug and fixed this issue?
> > 4) Is this related to power or any other pin interference to reset pin?
> >
> > I haven't more experience in LPC.Any experience persons,help me??
> >
> > Additional Information:
> > This reset issue happens randomly and some board i couldn't see this issue
>

--- In l..., prabuisin@... wrote:
>
> Hi,
> I am working on LPC2101.LPC is resetting randomly.
> I found the reset reason using RSIR registers.It shows external reset(Value is 2). From user guide,assertion of reset pin makes LPC to reset.

First thing I would look at is your power supply lines, especially if the RESET line is just pulled up to +3.3 Volts.

Also, do you have a small cap (~ 0.1 microfarad) across the RESET line and also one or two bypass caps across the +3.3V to GND lines ?

I'd look at my 3.3V with a scope. I bet you find it dropping momentarily...

Keep us posted.

boB

>
> 1) What are the conditions in LPC2101 to assert reset line automatically?
> 2) How to debug this in Software level as well as Hardware level?
> 3) If anybody faced this issue in already,
> Please share your knowledge about how did u debug and fixed this issue?
> 4) Is this related to power or any other pin interference to reset pin?
>
> I haven't more experience in LPC.Any experience persons,help me??
>
> Additional Information:
> This reset issue happens randomly and some board i couldn't see this issue
>

----- Original Message -----
From:
To:
Sent: Thursday, June 18, 2009 10:20 AM
Subject: [lpc2000] Final LPC Issue: External Reset happens randomly on
LPC2101
> Hi,
> I am working on LPC2101.LPC is resetting randomly.
> I found the reset reason using RSIR registers.It shows external
> reset(Value is 2). From user guide,assertion of reset pin makes LPC to
> reset.
>
> 1) What are the conditions in LPC2101 to assert reset line automatically?
> 2) How to debug this in Software level as well as Hardware level?
> 3) If anybody faced this issue in already,
> Please share your knowledge about how did u debug and fixed this issue?
> 4) Is this related to power or any other pin interference to reset pin?
>
> I haven't more experience in LPC.Any experience persons,help me??
>
> Additional Information:
> This reset issue happens randomly and some board i couldn't see this issue

What sort of environment is the board used in?

Leon

p...@yahoo.co.in wrote:
> 1) What are the conditions in LPC2101 to assert reset line automatically?

None. Reset line is an input. LPC can't assert it by itself.

> 2) How to debug this in Software level as well as Hardware level?

There is nothing to debug in software level, unless there is something
on your board which you can control by software to assert the reset -
e.g. external hardware watchdog. On hardware level you need scope or
something like that.

> 3) If anybody faced this issue in already,
> Please share your knowledge about how did u debug and fixed this issue?

If you have brown out detector on board, watch brief drops on your
supply voltage.

> 4) Is this related to power or any other pin interference to reset pin?

That depends on your board.

--

Timo

Hi,
I am working on LPC2101.LPC is resetting randomly.
I found the reset reason using RSIR registers.It shows external reset(Value is 2). From user guide,assertion of reset pin makes LPC to reset.

1) What are the conditions in LPC2101 to assert reset line automatically?
2) How to debug this in Software level as well as Hardware level?
3) If anybody faced this issue in already,
Please share your knowledge about how did u debug and fixed this issue?
4) Is this related to power or any other pin interference to reset pin?

I haven't more experience in LPC.Any experience persons,help me??

Additional Information:
This reset issue happens randomly and some board i couldn't see this issue