Hello All
We have designed a board based on Keil MCB 2103 board. The problem is that the
controller(LPC 2103) and the 1.8V regulator is heating up on power up.
On inspection we found out that the Pin number 5 of controller ie the 1.8v of
the core pin is getting shorted(grounded), later also found out that the
controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
Kindly find the schematic of the board here
http://www.esnips.com/doc/a8a98449-1be2-4cab-9b71-122d71a9942c/2103_SCH
This boards design is based on Keil MCB 2103 board.
The PCB for this project were all tested and verified to confirm with the
schematic. Also the after soldering all components the boards were tested and no
shorts or other problems were found. the shorts appear on power up.
We have prepared 6 boards this problem has occurred in 4 and the other 2 are
working.
The 2 working boards were programmed and we tested with simple serial
communication program (echo) it worked fine. But when tried to derive few port
pins to logic high it failed in doing so. This program ran smoothly in
debug(simulation) mode. When checking the port pins for there voltage it were
all in undefined state of 1.8V or so.
Have been trying to find the cause of the problem with out any success.Kindly
help in solving the problem.
Thanks and regards
Problem With LPC2103 Board,LPC2103 heating up- schematic provided
Started by ●May 5, 2009
Reply by ●May 5, 20092009-05-05
--- In l..., "AbhiShek" wrote:
>
> We have designed a board based on Keil MCB 2103 board. The problem is that the controller(LPC 2103) and the 1.8V regulator is heating up on power up.
> On inspection we found out that the Pin number 5 of controller ie the 1.8v of the core pin is getting shorted(grounded), later also found out that the controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
>
I would start by checking following:
What happens if you keep reset asserted? Levels OK? If not, locate where levels are wrong.
Can you measure the clock frequency and signal shape? Some wild oscillation problem?
And is the PCB design sane in terms of decoupling, ground etc? Is also the layout more or less taken from the Keil board?
--
Kind regards,
Walter
>
> We have designed a board based on Keil MCB 2103 board. The problem is that the controller(LPC 2103) and the 1.8V regulator is heating up on power up.
> On inspection we found out that the Pin number 5 of controller ie the 1.8v of the core pin is getting shorted(grounded), later also found out that the controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
>
I would start by checking following:
What happens if you keep reset asserted? Levels OK? If not, locate where levels are wrong.
Can you measure the clock frequency and signal shape? Some wild oscillation problem?
And is the PCB design sane in terms of decoupling, ground etc? Is also the layout more or less taken from the Keil board?
--
Kind regards,
Walter
Reply by ●May 5, 20092009-05-05
----- Original Message -----
From: "AbhiShek"
To:
Sent: Tuesday, May 05, 2009 12:11 PM
Subject: [lpc2000] Problem With LPC2103 Board,LPC2103 heating up- schematic
provided
> Hello All
>
> We have designed a board based on Keil MCB 2103 board. The problem is that
> the controller(LPC 2103) and the 1.8V regulator is heating up on power up.
> On inspection we found out that the Pin number 5 of controller ie the 1.8v
> of the core pin is getting shorted(grounded), later also found out that
> the controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
> Kindly find the schematic of the board here
>
> http://www.esnips.com/doc/a8a98449-1be2-4cab-9b71-122d71a9942c/2103_SCH
>
> This boards design is based on Keil MCB 2103 board.
>
> The PCB for this project were all tested and verified to confirm with the
> schematic. Also the after soldering all components the boards were tested
> and no shorts or other problems were found. the shorts appear on power up.
>
> We have prepared 6 boards this problem has occurred in 4 and the other 2
> are working.
>
> The 2 working boards were programmed and we tested with simple serial
> communication program (echo) it worked fine. But when tried to derive few
> port pins to logic high it failed in doing so. This program ran smoothly
> in debug(simulation) mode. When checking the port pins for there voltage
> it were all in undefined state of 1.8V or so.
>
> Have been trying to find the cause of the problem with out any
> success.Kindly help in solving the problem.
I would try building the board with the bare minumum on it (just enough to
support JTAG), and check it out. I always build the supply circuitry first
and make sure that is working properly before I add the MCU.
Then add additional stuff a bit at a time.
Leon
From: "AbhiShek"
To:
Sent: Tuesday, May 05, 2009 12:11 PM
Subject: [lpc2000] Problem With LPC2103 Board,LPC2103 heating up- schematic
provided
> Hello All
>
> We have designed a board based on Keil MCB 2103 board. The problem is that
> the controller(LPC 2103) and the 1.8V regulator is heating up on power up.
> On inspection we found out that the Pin number 5 of controller ie the 1.8v
> of the core pin is getting shorted(grounded), later also found out that
> the controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
> Kindly find the schematic of the board here
>
> http://www.esnips.com/doc/a8a98449-1be2-4cab-9b71-122d71a9942c/2103_SCH
>
> This boards design is based on Keil MCB 2103 board.
>
> The PCB for this project were all tested and verified to confirm with the
> schematic. Also the after soldering all components the boards were tested
> and no shorts or other problems were found. the shorts appear on power up.
>
> We have prepared 6 boards this problem has occurred in 4 and the other 2
> are working.
>
> The 2 working boards were programmed and we tested with simple serial
> communication program (echo) it worked fine. But when tried to derive few
> port pins to logic high it failed in doing so. This program ran smoothly
> in debug(simulation) mode. When checking the port pins for there voltage
> it were all in undefined state of 1.8V or so.
>
> Have been trying to find the cause of the problem with out any
> success.Kindly help in solving the problem.
I would try building the board with the bare minumum on it (just enough to
support JTAG), and check it out. I always build the supply circuitry first
and make sure that is working properly before I add the MCU.
Then add additional stuff a bit at a time.
Leon
Reply by ●May 5, 20092009-05-05
--- In l..., "leon Heller" wrote:
> I would try building the board with the bare minumum on it (just enough to
> support JTAG), and check it out. I always build the supply circuitry first
> and make sure that is working properly before I add the MCU.
>
OK, for hand crafted boards that can work very well. My aproach comes from my experiences in mass production trial runs. There the boards arrive fully assembled.
For a working JTAG you only need supply, clock and a reset circuit that at least does not constantly pull reset. Then you can start discovering the outside world from the core point of view by checking busses, memory and peripherals.
--
Kind regards,
Walter
> I would try building the board with the bare minumum on it (just enough to
> support JTAG), and check it out. I always build the supply circuitry first
> and make sure that is working properly before I add the MCU.
>
OK, for hand crafted boards that can work very well. My aproach comes from my experiences in mass production trial runs. There the boards arrive fully assembled.
For a working JTAG you only need supply, clock and a reset circuit that at least does not constantly pull reset. Then you can start discovering the outside world from the core point of view by checking busses, memory and peripherals.
--
Kind regards,
Walter
Reply by ●May 5, 20092009-05-05
----- Original Message -----
From: "Walter"
To:
Sent: Tuesday, May 05, 2009 3:05 PM
Subject: [lpc2000] Re: Problem With LPC2103 Board,LPC2103 heating up-
schematic provided
> --- In l..., "leon Heller" wrote:
>> I would try building the board with the bare minumum on it (just enough
>> to
>> support JTAG), and check it out. I always build the supply circuitry
>> first
>> and make sure that is working properly before I add the MCU.
>>
> OK, for hand crafted boards that can work very well. My aproach comes from
> my experiences in mass production trial runs. There the boards arrive
> fully assembled.
>
> For a working JTAG you only need supply, clock and a reset circuit that at
> least does not constantly pull reset. Then you can start discovering the
> outside world from the core point of view by checking busses, memory and
> peripherals.
I think that the OP is at the prototyping stage, when it is best to assemble
and debug a board in stages..
Leon
From: "Walter"
To:
Sent: Tuesday, May 05, 2009 3:05 PM
Subject: [lpc2000] Re: Problem With LPC2103 Board,LPC2103 heating up-
schematic provided
> --- In l..., "leon Heller" wrote:
>> I would try building the board with the bare minumum on it (just enough
>> to
>> support JTAG), and check it out. I always build the supply circuitry
>> first
>> and make sure that is working properly before I add the MCU.
>>
> OK, for hand crafted boards that can work very well. My aproach comes from
> my experiences in mass production trial runs. There the boards arrive
> fully assembled.
>
> For a working JTAG you only need supply, clock and a reset circuit that at
> least does not constantly pull reset. Then you can start discovering the
> outside world from the core point of view by checking busses, memory and
> peripherals.
I think that the OP is at the prototyping stage, when it is best to assemble
and debug a board in stages..
Leon
Reply by ●May 6, 20092009-05-06
Hello all
thanks for all your suggestions.
the board is powered by 7.4V,1200mAHr Li ion battery with
I had not checked reset pin status till suggested by Mr.Walter.
On checking i found out it to be in undetermined state as rest of the pins.I provided a manual rest switch on doing so, the pin logic level returns to normal operating range of 0V-0.8V on logic 0 and 3V to 3.3V on logic 1.all the other controller pins which were in undetermined state too are in normal levels.
I have checked the clock signal for its frequency and shape both are stable and in good shape.
the board right now im working with only has basic block consisting of controller, power supply and the UART ISP block. just good enough to program and verify its working.
the PCB is manufactured prototype board and not hand made.
right now testing some more on it to verify and identify the cause of the undetermined state.
thanks all for your help.
thanks Mr.Walter for your help. it helped me a lot on identifying the problem.
i will update the topic later
thanks for all your suggestions.
the board is powered by 7.4V,1200mAHr Li ion battery with
I had not checked reset pin status till suggested by Mr.Walter.
On checking i found out it to be in undetermined state as rest of the pins.I provided a manual rest switch on doing so, the pin logic level returns to normal operating range of 0V-0.8V on logic 0 and 3V to 3.3V on logic 1.all the other controller pins which were in undetermined state too are in normal levels.
I have checked the clock signal for its frequency and shape both are stable and in good shape.
the board right now im working with only has basic block consisting of controller, power supply and the UART ISP block. just good enough to program and verify its working.
the PCB is manufactured prototype board and not hand made.
right now testing some more on it to verify and identify the cause of the undetermined state.
thanks all for your help.
thanks Mr.Walter for your help. it helped me a lot on identifying the problem.
i will update the topic later
Reply by ●May 7, 20092009-05-07
--- In l..., "AbhiShek" wrote:
>
> I had not checked reset pin status till suggested by Mr.Walter.
>
> On checking i found out it to be in undetermined state as rest of the pins.I provided a manual rest switch on doing so, the pin logic level returns to normal operating range of 0V-0.8V on logic 0 and 3V to 3.3V on logic 1.all the other controller pins which were in undetermined state too are in normal levels.
>
Good to hear that you made progress on this issue.
What I used to check in such cases is current consumption while under reset and after releasing reset. For a new design the values will not be known, but in general you should see an increase after release.
I seen layout related problems causing SDRAM clock to go to double or triple frequency when starting, bringing the controller into fully random state with high power consumption. (on NXP controllers)
Also an incorrectly as output configured IO pin connected to ground can bring a controller into problems. For that reason most pins are input after reset, and need SW interaction to act as output.
--
Kind regards,
Walter
>
> I had not checked reset pin status till suggested by Mr.Walter.
>
> On checking i found out it to be in undetermined state as rest of the pins.I provided a manual rest switch on doing so, the pin logic level returns to normal operating range of 0V-0.8V on logic 0 and 3V to 3.3V on logic 1.all the other controller pins which were in undetermined state too are in normal levels.
>
Good to hear that you made progress on this issue.
What I used to check in such cases is current consumption while under reset and after releasing reset. For a new design the values will not be known, but in general you should see an increase after release.
I seen layout related problems causing SDRAM clock to go to double or triple frequency when starting, bringing the controller into fully random state with high power consumption. (on NXP controllers)
Also an incorrectly as output configured IO pin connected to ground can bring a controller into problems. For that reason most pins are input after reset, and need SW interaction to act as output.
--
Kind regards,
Walter
Reply by ●May 7, 20092009-05-07
Your schematic shows a 1uF cap on the reset line. This is way too large. The
Keil board has a 0.1uF if I remember correctly. Try reducing the cap (c21 on
your schematic) to 0.1uF. Also I would recommend using a MCU supervisory device
such as the Exar SP809N. With that you can do away with the cap and just
maintain the pull up resistor on the reset line. I like to use the open drain
version (N suffix) so the JTAG can pull the reset low when debugging.
Frank
--- In l..., "AbhiShek" wrote:
>
> Hello All
>
> We have designed a board based on Keil MCB 2103 board. The problem is that the controller(LPC 2103) and the 1.8V regulator is heating up on power up.
> On inspection we found out that the Pin number 5 of controller ie the 1.8v of the core pin is getting shorted(grounded), later also found out that the controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
> Kindly find the schematic of the board here
> http://www.esnips.com/doc/a8a98449-1be2-4cab-9b71-122d71a9942c/2103_SCH
>
> This boards design is based on Keil MCB 2103 board.
>
> The PCB for this project were all tested and verified to confirm with the schematic. Also the after soldering all components the boards were tested and no shorts or other problems were found. the shorts appear on power up.
>
> We have prepared 6 boards this problem has occurred in 4 and the other 2 are working.
>
> The 2 working boards were programmed and we tested with simple serial communication program (echo) it worked fine. But when tried to derive few port pins to logic high it failed in doing so. This program ran smoothly in debug(simulation) mode. When checking the port pins for there voltage it were all in undefined state of 1.8V or so.
>
> Have been trying to find the cause of the problem with out any success.Kindly help in solving the problem.
>
> Thanks and regards
>
Frank
--- In l..., "AbhiShek" wrote:
>
> Hello All
>
> We have designed a board based on Keil MCB 2103 board. The problem is that the controller(LPC 2103) and the 1.8V regulator is heating up on power up.
> On inspection we found out that the Pin number 5 of controller ie the 1.8v of the core pin is getting shorted(grounded), later also found out that the controller Vdd3.3v pin number 17 and pin 19(Vss) are getting short.
> Kindly find the schematic of the board here
> http://www.esnips.com/doc/a8a98449-1be2-4cab-9b71-122d71a9942c/2103_SCH
>
> This boards design is based on Keil MCB 2103 board.
>
> The PCB for this project were all tested and verified to confirm with the schematic. Also the after soldering all components the boards were tested and no shorts or other problems were found. the shorts appear on power up.
>
> We have prepared 6 boards this problem has occurred in 4 and the other 2 are working.
>
> The 2 working boards were programmed and we tested with simple serial communication program (echo) it worked fine. But when tried to derive few port pins to logic high it failed in doing so. This program ran smoothly in debug(simulation) mode. When checking the port pins for there voltage it were all in undefined state of 1.8V or so.
>
> Have been trying to find the cause of the problem with out any success.Kindly help in solving the problem.
>
> Thanks and regards
>
