Hello,
During tests of my new card, it seems I have burnt 3 digital inputs on my
LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins wheter I configure them
as digital inputs or outputs).
I applied 5V logic levels on these inputs and tried to read them.
This worked during a while.
To me, two things may have happened:
- LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
- program updates using "ULINK" while 5V was still applied on these inputs.
Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't know
what is the reason.
If this was caused by program updates, this is not a problem: I only have to
replace the LPC2138 and load program only when 5V is OFF.
But if it is caused by ON/OFF, it is a problem for me. This means that I have
power ON the LPC2138 before the 5V equipment...
Has anyone an idea of what happened please?
Thanks very much!
Daniel
LPC2138 5V tolerant GPIO
Started by ●October 6, 2009
Reply by ●October 6, 20092009-10-06
--- In l..., "dsourgen" wrote:
>
> During tests of my new card, it seems I have burnt 3 digital inputs
> on my LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins
> wheter I configure them as digital inputs or outputs).
>
> I applied 5V logic levels on these inputs and tried to read them.
> This worked during a while.
>
> To me, two things may have happened:
> - LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
> - program updates using "ULINK" while 5V was still applied on these
> inputs.
>
> Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't
> know what is the reason.
>
> If this was caused by program updates, this is not a problem: I
> only have to replace the LPC2138 and load program only when 5V is
> OFF.
> But if it is caused by ON/OFF, it is a problem for me. This means
> that I have power ON the LPC2138 before the 5V equipment...
>
> Has anyone an idea of what happened please?
The inputs are only 5V tolerant when VDD is present. It is not very clear from the LPC2138 datasheet. See "Limiting values".
Karl Olsen
>
> During tests of my new card, it seems I have burnt 3 digital inputs
> on my LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins
> wheter I configure them as digital inputs or outputs).
>
> I applied 5V logic levels on these inputs and tried to read them.
> This worked during a while.
>
> To me, two things may have happened:
> - LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
> - program updates using "ULINK" while 5V was still applied on these
> inputs.
>
> Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't
> know what is the reason.
>
> If this was caused by program updates, this is not a problem: I
> only have to replace the LPC2138 and load program only when 5V is
> OFF.
> But if it is caused by ON/OFF, it is a problem for me. This means
> that I have power ON the LPC2138 before the 5V equipment...
>
> Has anyone an idea of what happened please?
The inputs are only 5V tolerant when VDD is present. It is not very clear from the LPC2138 datasheet. See "Limiting values".
Karl Olsen
Reply by ●October 6, 20092009-10-06
----- Original Message -----
From: "dsourgen"
To:
Sent: Tuesday, October 06, 2009 2:46 PM
Subject: [lpc2000] LPC2138 5V tolerant GPIO
> Hello,
>
> During tests of my new card, it seems I have burnt 3 digital inputs on my
> LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins wheter I configure
> them as digital inputs or outputs).
>
> I applied 5V logic levels on these inputs and tried to read them.
> This worked during a while.
>
> To me, two things may have happened:
> - LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
> - program updates using "ULINK" while 5V was still applied on these
> inputs.
>
> Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't know
> what is the reason.
>
> If this was caused by program updates, this is not a problem: I only have
> to replace the LPC2138 and load program only when 5V is OFF.
> But if it is caused by ON/OFF, it is a problem for me. This means that I
> have power ON the LPC2138 before the 5V equipment...
>
> Has anyone an idea of what happened please?
Applying a voltage to an MCU pin with the power off isn't generally
advisable. The 5V tolerance probably only applies if the 3.3V I/O supply is
present.
Leon
Leon
From: "dsourgen"
To:
Sent: Tuesday, October 06, 2009 2:46 PM
Subject: [lpc2000] LPC2138 5V tolerant GPIO
> Hello,
>
> During tests of my new card, it seems I have burnt 3 digital inputs on my
> LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins wheter I configure
> them as digital inputs or outputs).
>
> I applied 5V logic levels on these inputs and tried to read them.
> This worked during a while.
>
> To me, two things may have happened:
> - LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
> - program updates using "ULINK" while 5V was still applied on these
> inputs.
>
> Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't know
> what is the reason.
>
> If this was caused by program updates, this is not a problem: I only have
> to replace the LPC2138 and load program only when 5V is OFF.
> But if it is caused by ON/OFF, it is a problem for me. This means that I
> have power ON the LPC2138 before the 5V equipment...
>
> Has anyone an idea of what happened please?
Applying a voltage to an MCU pin with the power off isn't generally
advisable. The 5V tolerance probably only applies if the 3.3V I/O supply is
present.
Leon
Leon
Reply by ●October 6, 20092009-10-06
--- In l..., "Karl" wrote:
>
> --- In l..., "dsourgen" wrote:
> >
> > During tests of my new card, it seems I have burnt 3 digital inputs
> > on my LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins
> > wheter I configure them as digital inputs or outputs).
> >
> > I applied 5V logic levels on these inputs and tried to read them.
> > This worked during a while.
> >
> > To me, two things may have happened:
> > - LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
> > - program updates using "ULINK" while 5V was still applied on these
> > inputs.
> >
> > Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't
> > know what is the reason.
> >
> > If this was caused by program updates, this is not a problem: I
> > only have to replace the LPC2138 and load program only when 5V is
> > OFF.
> > But if it is caused by ON/OFF, it is a problem for me. This means
> > that I have power ON the LPC2138 before the 5V equipment...
> >
> > Has anyone an idea of what happened please?
>
> The inputs are only 5V tolerant when VDD is present. It is not very clear from the LPC2138 datasheet. See "Limiting values".
>
> Karl Olsen
>
Hello Karl,
Thanks for your answer.
I have seen this note in the datasheet (after my problem...).
I would like to know what is the risk? Is it destructive like in my case? Maybe someone already experienced it?
Like you said, the note is not very clear... Can we apply a 3.3V level when the LPC2138 is OFF?
Daniel
>
> --- In l..., "dsourgen" wrote:
> >
> > During tests of my new card, it seems I have burnt 3 digital inputs
> > on my LPC2138: P0.28, P0.29, P0.30 (No reaction on these pins
> > wheter I configure them as digital inputs or outputs).
> >
> > I applied 5V logic levels on these inputs and tried to read them.
> > This worked during a while.
> >
> > To me, two things may have happened:
> > - LPC2138 "ON <-> OFF" while 5V was still applied on these inputs.
> > - program updates using "ULINK" while 5V was still applied on these
> > inputs.
> >
> > Now, all of the LPC2138 seems to be ok except these 3 I/Os. I don't
> > know what is the reason.
> >
> > If this was caused by program updates, this is not a problem: I
> > only have to replace the LPC2138 and load program only when 5V is
> > OFF.
> > But if it is caused by ON/OFF, it is a problem for me. This means
> > that I have power ON the LPC2138 before the 5V equipment...
> >
> > Has anyone an idea of what happened please?
>
> The inputs are only 5V tolerant when VDD is present. It is not very clear from the LPC2138 datasheet. See "Limiting values".
>
> Karl Olsen
>
Hello Karl,
Thanks for your answer.
I have seen this note in the datasheet (after my problem...).
I would like to know what is the risk? Is it destructive like in my case? Maybe someone already experienced it?
Like you said, the note is not very clear... Can we apply a 3.3V level when the LPC2138 is OFF?
Daniel
Reply by ●October 6, 20092009-10-06
----- Original Message -----
From: "dsourgen"
To:
Sent: Tuesday, October 06, 2009 3:36 PM
Subject: [lpc2000] Re: LPC2138 5V tolerant GPIO
> Thanks for your answer.
> I have seen this note in the datasheet (after my problem...).
> I would like to know what is the risk? Is it destructive like in my case?
> Maybe someone already experienced it?
> Like you said, the note is not very clear... Can we apply a 3.3V level
> when the LPC2138 is OFF?
That's not safe either. 5V tolerant pins shouldn't have any voltage on them
with no Vdd present, according to the Limiting Values table. That's my
interpretation of it, anyway. 0.5V max. on non-5V tolerant pins as the max.
value is Vdd + 0.5V.
Leon
From: "dsourgen"
To:
Sent: Tuesday, October 06, 2009 3:36 PM
Subject: [lpc2000] Re: LPC2138 5V tolerant GPIO
> Thanks for your answer.
> I have seen this note in the datasheet (after my problem...).
> I would like to know what is the risk? Is it destructive like in my case?
> Maybe someone already experienced it?
> Like you said, the note is not very clear... Can we apply a 3.3V level
> when the LPC2138 is OFF?
That's not safe either. 5V tolerant pins shouldn't have any voltage on them
with no Vdd present, according to the Limiting Values table. That's my
interpretation of it, anyway. 0.5V max. on non-5V tolerant pins as the max.
value is Vdd + 0.5V.
Leon
Reply by ●October 6, 20092009-10-06
Hi,
I had a similar problem; my experience was that if you put 5V on i/o without
3.3V in Vdd, you burn the i/o pin and in some cases, the device becomes
silent (oscillator works, but the device does nothing)
cordiales saludos,
Pedro Ignacio Martos
p...@fi.uba.ar
http://www.fi.uba.ar/~pmartos/
----- Original Message -----
From: dsourgen
To: l...
Sent: Tuesday, October 06, 2009 11:36 AM
Subject: [lpc2000] Re: LPC2138 5V tolerant GPIO
>
> The inputs are only 5V tolerant when VDD is present. It is not very clear
> from the LPC2138 datasheet. See "Limiting values".
>
> Karl Olsen
>
Hello Karl,
Thanks for your answer.
I have seen this note in the datasheet (after my problem...).
I would like to know what is the risk? Is it destructive like in my case?
Maybe someone already experienced it?
Like you said, the note is not very clear... Can we apply a 3.3V level when
the LPC2138 is OFF?
Daniel
I had a similar problem; my experience was that if you put 5V on i/o without
3.3V in Vdd, you burn the i/o pin and in some cases, the device becomes
silent (oscillator works, but the device does nothing)
cordiales saludos,
Pedro Ignacio Martos
p...@fi.uba.ar
http://www.fi.uba.ar/~pmartos/
----- Original Message -----
From: dsourgen
To: l...
Sent: Tuesday, October 06, 2009 11:36 AM
Subject: [lpc2000] Re: LPC2138 5V tolerant GPIO
>
> The inputs are only 5V tolerant when VDD is present. It is not very clear
> from the LPC2138 datasheet. See "Limiting values".
>
> Karl Olsen
>
Hello Karl,
Thanks for your answer.
I have seen this note in the datasheet (after my problem...).
I would like to know what is the risk? Is it destructive like in my case?
Maybe someone already experienced it?
Like you said, the note is not very clear... Can we apply a 3.3V level when
the LPC2138 is OFF?
Daniel
Reply by ●October 7, 20092009-10-07
Thank you Leon and Pedro.
I replaced the LPC2138 on my card and tested it this morning. All is working well. Now, I have to modify it to ensure that users will always power this card ON before equipments connected to it.
Thanks again for answers,
Daniel
--- In l..., "Ignacio" wrote:
>
> Hi,
>
> I had a similar problem; my experience was that if you put 5V on i/o without
> 3.3V in Vdd, you burn the i/o pin and in some cases, the device becomes
> silent (oscillator works, but the device does nothing)
>
> cordiales saludos,
> Pedro Ignacio Martos
> pmartos@...
> http://www.fi.uba.ar/~pmartos/
> ----- Original Message -----
> From: dsourgen
> To: l...
> Sent: Tuesday, October 06, 2009 11:36 AM
> Subject: [lpc2000] Re: LPC2138 5V tolerant GPIO
>
> >
> > The inputs are only 5V tolerant when VDD is present. It is not very clear
> > from the LPC2138 datasheet. See "Limiting values".
> >
> > Karl Olsen
> > Hello Karl,
>
> Thanks for your answer.
> I have seen this note in the datasheet (after my problem...).
> I would like to know what is the risk? Is it destructive like in my case?
> Maybe someone already experienced it?
> Like you said, the note is not very clear... Can we apply a 3.3V level when
> the LPC2138 is OFF?
>
> Daniel
>
I replaced the LPC2138 on my card and tested it this morning. All is working well. Now, I have to modify it to ensure that users will always power this card ON before equipments connected to it.
Thanks again for answers,
Daniel
--- In l..., "Ignacio" wrote:
>
> Hi,
>
> I had a similar problem; my experience was that if you put 5V on i/o without
> 3.3V in Vdd, you burn the i/o pin and in some cases, the device becomes
> silent (oscillator works, but the device does nothing)
>
> cordiales saludos,
> Pedro Ignacio Martos
> pmartos@...
> http://www.fi.uba.ar/~pmartos/
> ----- Original Message -----
> From: dsourgen
> To: l...
> Sent: Tuesday, October 06, 2009 11:36 AM
> Subject: [lpc2000] Re: LPC2138 5V tolerant GPIO
>
> >
> > The inputs are only 5V tolerant when VDD is present. It is not very clear
> > from the LPC2138 datasheet. See "Limiting values".
> >
> > Karl Olsen
> > Hello Karl,
>
> Thanks for your answer.
> I have seen this note in the datasheet (after my problem...).
> I would like to know what is the risk? Is it destructive like in my case?
> Maybe someone already experienced it?
> Like you said, the note is not very clear... Can we apply a 3.3V level when
> the LPC2138 is OFF?
>
> Daniel
>
