Hi Vinaya,
Did you solve this problem with low level on reset pin ?
I'm having the same issue with lpc2138 chip right now.
Regards,
Darek
Hi all,
>We have developed a LPC2378 board.One board is fully
working with all possible interfaces (SPI,UART,Ethernet etc) and i was using the
JTAG emulator to load / debug the software. I want to test the ISP feature , so
i have taken up another board.I have assembled the bare minimum components
necessary for ISP alone.ISP is not working.On tracing i found that the reset pin
is floating.The reset pin is pulled up thru a 10K resistor.So one end of this
resistor shows 3.3v ,But the other end(connected to the reset pin(pin 24)shows a
level of around 600mv.So the processor may not be running at all i guess.Unable
to find out why.(A reset switch is also connected to the reset pin for giving
external reset,but i have isolated this too.)
>Any suggestions please? Thanks in advance,
>Vinaya
>
>
Re: LPC2378 reset pin problem
Started by ●October 18, 2011
Reply by ●October 18, 20112011-10-18
At the risk of saying 'me too' - I'm also having exactly the same
issue with an LPC2106!
Out of a batch of 6 PCBs I had made 2 of them have subsequently failed with the reset pin being pulled low by the LPC2106 itself (it would appear it tries to sink a fair amount of current too).
One of the PCBs failed whilst in the Philips bootloader and the other PCB failed whilst running user code.
The only clue I've got is that the power supply on my PCB is performing very badly - it's a badly laid out switcher with insufficient de-coupling and it produces 0.5v peak-to-peak spikes on the 3V3 supply and around 0.2V peak-to-peak spikes on the 1V8 rail. I think this is somehow destroying the LPC2106 causing the behaviour we see on the reset pin.
Obviously I'm rectifying the problems with the power supply for the next revision of my PCB, however I'd like to be 100% sure that this was the cause of the 2 LPC2106 failures.
Does this ring a bell with anyone?
--- In l..., misiekdarek@... wrote:
>
> Hi Vinaya,
>
> Did you solve this problem with low level on reset pin ?
> I'm having the same issue with lpc2138 chip right now.
>
> Regards,
> Darek
>
> Hi all,
> >We have developed a LPC2378 board.One board is fully working with all possible interfaces (SPI,UART,Ethernet etc) and i was using the JTAG emulator to load / debug the software. I want to test the ISP feature , so i have taken up another board.I have assembled the bare minimum components necessary for ISP alone.ISP is not working.On tracing i found that the reset pin is floating.The reset pin is pulled up thru a 10K resistor.So one end of this resistor shows 3.3v ,But the other end(connected to the reset pin(pin 24)shows a level of around 600mv.So the processor may not be running at all i guess.Unable to find out why.(A reset switch is also connected to the reset pin for giving external reset,but i have isolated this too.)
> >Any suggestions please? Thanks in advance,
> >Vinaya
> >
> >
> >
>
Out of a batch of 6 PCBs I had made 2 of them have subsequently failed with the reset pin being pulled low by the LPC2106 itself (it would appear it tries to sink a fair amount of current too).
One of the PCBs failed whilst in the Philips bootloader and the other PCB failed whilst running user code.
The only clue I've got is that the power supply on my PCB is performing very badly - it's a badly laid out switcher with insufficient de-coupling and it produces 0.5v peak-to-peak spikes on the 3V3 supply and around 0.2V peak-to-peak spikes on the 1V8 rail. I think this is somehow destroying the LPC2106 causing the behaviour we see on the reset pin.
Obviously I'm rectifying the problems with the power supply for the next revision of my PCB, however I'd like to be 100% sure that this was the cause of the 2 LPC2106 failures.
Does this ring a bell with anyone?
--- In l..., misiekdarek@... wrote:
>
> Hi Vinaya,
>
> Did you solve this problem with low level on reset pin ?
> I'm having the same issue with lpc2138 chip right now.
>
> Regards,
> Darek
>
> Hi all,
> >We have developed a LPC2378 board.One board is fully working with all possible interfaces (SPI,UART,Ethernet etc) and i was using the JTAG emulator to load / debug the software. I want to test the ISP feature , so i have taken up another board.I have assembled the bare minimum components necessary for ISP alone.ISP is not working.On tracing i found that the reset pin is floating.The reset pin is pulled up thru a 10K resistor.So one end of this resistor shows 3.3v ,But the other end(connected to the reset pin(pin 24)shows a level of around 600mv.So the processor may not be running at all i guess.Unable to find out why.(A reset switch is also connected to the reset pin for giving external reset,but i have isolated this too.)
> >Any suggestions please? Thanks in advance,
> >Vinaya
> >
> >
> >
>
Reply by ●October 18, 20112011-10-18
--- In l..., "Martin" wrote:
>
> At the risk of saying 'me too' - I'm also having exactly the same issue with an LPC2106!
>
> Out of a batch of 6 PCBs I had made 2 of them have subsequently failed with the reset pin being pulled low by the LPC2106 itself (it would appear it tries to sink a fair amount of current too).
>
> One of the PCBs failed whilst in the Philips bootloader and the other PCB failed whilst running user code.
>
> The only clue I've got is that the power supply on my PCB is performing very badly - it's a badly laid out switcher with insufficient de-coupling and it produces 0.5v peak-to-peak spikes on the 3V3 supply and around 0.2V peak-to-peak spikes on the 1V8 rail. I think this is somehow destroying the LPC2106 causing the behaviour we see on the reset pin.
>
> Obviously I'm rectifying the problems with the power supply for the next revision of my PCB, however I'd like to be 100% sure that this was the cause of the 2 LPC2106 failures.
>
> Does this ring a bell with anyone?
>
Yes, I have seen parts on occasion where the failure was that a pin would short itself high or low. Can't remember if it was a reset pin or not though and it wasn't an LPC2106 but this may have happened a long time ago on an LPC2103 and I think I've seen a couple of failures like that on another LPCxxxx part or 2 or 3.
I never quite figured out why this would happen. It wasn't a direct short, but around 100 Ohms maybe. Low enough to keep things from working anymore and then having to replace the chip of course.
If the pin is accessible to the outside world, like a reset pin going to a reset button, it might be a good idea to add a resistor from the pin to the button and pullup as well as a cap to ground or Vcc on the pin to help reduce any static electricity transients when the user sparks the reset button with their finger.
boB
>
> At the risk of saying 'me too' - I'm also having exactly the same issue with an LPC2106!
>
> Out of a batch of 6 PCBs I had made 2 of them have subsequently failed with the reset pin being pulled low by the LPC2106 itself (it would appear it tries to sink a fair amount of current too).
>
> One of the PCBs failed whilst in the Philips bootloader and the other PCB failed whilst running user code.
>
> The only clue I've got is that the power supply on my PCB is performing very badly - it's a badly laid out switcher with insufficient de-coupling and it produces 0.5v peak-to-peak spikes on the 3V3 supply and around 0.2V peak-to-peak spikes on the 1V8 rail. I think this is somehow destroying the LPC2106 causing the behaviour we see on the reset pin.
>
> Obviously I'm rectifying the problems with the power supply for the next revision of my PCB, however I'd like to be 100% sure that this was the cause of the 2 LPC2106 failures.
>
> Does this ring a bell with anyone?
>
Yes, I have seen parts on occasion where the failure was that a pin would short itself high or low. Can't remember if it was a reset pin or not though and it wasn't an LPC2106 but this may have happened a long time ago on an LPC2103 and I think I've seen a couple of failures like that on another LPCxxxx part or 2 or 3.
I never quite figured out why this would happen. It wasn't a direct short, but around 100 Ohms maybe. Low enough to keep things from working anymore and then having to replace the chip of course.
If the pin is accessible to the outside world, like a reset pin going to a reset button, it might be a good idea to add a resistor from the pin to the button and pullup as well as a cap to ground or Vcc on the pin to help reduce any static electricity transients when the user sparks the reset button with their finger.
boB
Reply by ●October 19, 20112011-10-19
Yes , the problem was eventually solved. The problem was with the transistors (
2 of them) in the ISP circuit which was the same as in the MCB2300 demo board.
the transistors were not mounted correctly, the B , E, C pins were all jumbled
up , the footprint was put as in the leaded version of transistors(the pin
numbering is different in SMD transistors). With the correction , the reset pin
was proper and ISP also worked.
regards,
vinaya
--- In l..., misiekdarek@... wrote:
>
> Hi Vinaya,
>
> Did you solve this problem with low level on reset pin ?
> I'm having the same issue with lpc2138 chip right now.
>
> Regards,
> Darek
>
> Hi all,
> >We have developed a LPC2378 board.One board is fully working with all possible interfaces (SPI,UART,Ethernet etc) and i was using the JTAG emulator to load / debug the software. I want to test the ISP feature , so i have taken up another board.I have assembled the bare minimum components necessary for ISP alone.ISP is not working.On tracing i found that the reset pin is floating.The reset pin is pulled up thru a 10K resistor.So one end of this resistor shows 3.3v ,But the other end(connected to the reset pin(pin 24)shows a level of around 600mv.So the processor may not be running at all i guess.Unable to find out why.(A reset switch is also connected to the reset pin for giving external reset,but i have isolated this too.)
> >Any suggestions please? Thanks in advance,
> >Vinaya
> >
> >
> >
>
regards,
vinaya
--- In l..., misiekdarek@... wrote:
>
> Hi Vinaya,
>
> Did you solve this problem with low level on reset pin ?
> I'm having the same issue with lpc2138 chip right now.
>
> Regards,
> Darek
>
> Hi all,
> >We have developed a LPC2378 board.One board is fully working with all possible interfaces (SPI,UART,Ethernet etc) and i was using the JTAG emulator to load / debug the software. I want to test the ISP feature , so i have taken up another board.I have assembled the bare minimum components necessary for ISP alone.ISP is not working.On tracing i found that the reset pin is floating.The reset pin is pulled up thru a 10K resistor.So one end of this resistor shows 3.3v ,But the other end(connected to the reset pin(pin 24)shows a level of around 600mv.So the processor may not be running at all i guess.Unable to find out why.(A reset switch is also connected to the reset pin for giving external reset,but i have isolated this too.)
> >Any suggestions please? Thanks in advance,
> >Vinaya
> >
> >
> >
>
Reply by ●October 24, 20112011-10-24
Hi All,
I hope this post will help someone. In my case this was a short between the
reset pin and an another one made by tiny piece of dirt.
When I cleaned it up everything started to work.
Darek
2011/10/19 pintvin
> **
>
> Yes , the problem was eventually solved. The problem was with the
> transistors ( 2 of them) in the ISP circuit which was the same as in the
> MCB2300 demo board. the transistors were not mounted correctly, the B , E, C
> pins were all jumbled up , the footprint was put as in the leaded version of
> transistors(the pin numbering is different in SMD transistors). With the
> correction , the reset pin was proper and ISP also worked.
> regards,
> vinaya
>
> --- In l..., misiekdarek@... wrote:
> >
> > Hi Vinaya,
> >
> > Did you solve this problem with low level on reset pin ?
> > I'm having the same issue with lpc2138 chip right now.
> >
> > Regards,
> > Darek
> >
> > Hi all,
> > >We have developed a LPC2378 board.One board is fully working with all
> possible interfaces (SPI,UART,Ethernet etc) and i was using the JTAG
> emulator to load / debug the software. I want to test the ISP feature , so i
> have taken up another board.I have assembled the bare minimum components
> necessary for ISP alone.ISP is not working.On tracing i found that the reset
> pin is floating.The reset pin is pulled up thru a 10K resistor.So one end of
> this resistor shows 3.3v ,But the other end(connected to the reset pin(pin
> 24)shows a level of around 600mv.So the processor may not be running at all
> i guess.Unable to find out why.(A reset switch is also connected to the
> reset pin for giving external reset,but i have isolated this too.)
> > >Any suggestions please? Thanks in advance,
> > >Vinaya
> > >
> > >
> > >
> > >
> >
>
I hope this post will help someone. In my case this was a short between the
reset pin and an another one made by tiny piece of dirt.
When I cleaned it up everything started to work.
Darek
2011/10/19 pintvin
> **
>
> Yes , the problem was eventually solved. The problem was with the
> transistors ( 2 of them) in the ISP circuit which was the same as in the
> MCB2300 demo board. the transistors were not mounted correctly, the B , E, C
> pins were all jumbled up , the footprint was put as in the leaded version of
> transistors(the pin numbering is different in SMD transistors). With the
> correction , the reset pin was proper and ISP also worked.
> regards,
> vinaya
>
> --- In l..., misiekdarek@... wrote:
> >
> > Hi Vinaya,
> >
> > Did you solve this problem with low level on reset pin ?
> > I'm having the same issue with lpc2138 chip right now.
> >
> > Regards,
> > Darek
> >
> > Hi all,
> > >We have developed a LPC2378 board.One board is fully working with all
> possible interfaces (SPI,UART,Ethernet etc) and i was using the JTAG
> emulator to load / debug the software. I want to test the ISP feature , so i
> have taken up another board.I have assembled the bare minimum components
> necessary for ISP alone.ISP is not working.On tracing i found that the reset
> pin is floating.The reset pin is pulled up thru a 10K resistor.So one end of
> this resistor shows 3.3v ,But the other end(connected to the reset pin(pin
> 24)shows a level of around 600mv.So the processor may not be running at all
> i guess.Unable to find out why.(A reset switch is also connected to the
> reset pin for giving external reset,but i have isolated this too.)
> > >Any suggestions please? Thanks in advance,
> > >Vinaya
> > >
> > >
> > >
> > >
> >
>
