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TIVA C Launch Pad Fails at below 0 C and above 40 C temperatures


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Hello,

 

has any body have experience with the TIVA C Launch Pad failing at below 0 C temperatures?

and also at 40 C  and higher Temperatures?

 

My Launch Pad running UART0, ADC0 with Sequences 0 and 1, and PWM1 with 4 complementary channels for PWM control of motor fails at - C temperatures and above 40 C temperatures.

 

I have contacted Texas Instruments about this issue but they don't seem to want to help much

other than tells us to go to forums and ask engineers there.

 

If you are developing around the TIVA C parts beware of issues with Temperatures.

 

We have already tested the TM4C123GH6PMI and the TM4C133BE6PMI chips and both parts fail

miserably.

 

Thanks.

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FYI there's a sister forum to this dedicated to the Stellaris and Tiva-C platforms -- http://forum.stellarisiti.com/

 

So you tested the chips on separate boards of your own in these temps?  That's a bit disturbing if so.  What other components were included on those?

edit: and how did they fail?

 

For reference, tm4c123gh6pm datasheet: http://www.ti.com/lit/ds/symlink/tm4c123gh6pm.pdf page 1354 mentions ambient operating temp range of -40 to +85C (industrial)

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... I have contacted Texas Instruments about this issue but they don't seem to want to help much other than tells us to go to forums and ask engineers there....

So did you follow the advice given?

 

*edit= I don't see anything saying the LP is rated to extreme temps; just the chip.

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So did you follow the advice given?

 

*edit= I don't see anything saying the LP is rated to extreme temps; just the chip.

Looks like it: http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/309639.aspx

More detail there.  It's a customer's board that initially had this fault (with the launchpad being used to develop the firmware).  Wow... that sounds pretty nasty (so far with the information supplied).  No replies yet but it'll be interesting to see what comes of it.

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Thank you guys for your responses.

 

spirilis

 

Our board design around the TIVA C TM4C123BE6PMI rated for a temperature range of -40C to 85C (Industrial)

and made 22 boards for on field testing by our customer.  We initially develop the code on the TIVAC Launchpad

which uses the TM4C123GH6PMI also rated for Industrial temperature range.  

 

Customer install the boards on the field for testing and found that when temperatures were below 0C, in fact -4C

they so the boards fail to run the motor in which they were design to control.

 

So, we conducted our own test here at our place by running the board with a motor attached and run by Lead Acid Batteries

in side a freezer set to a temperature of -18C.  

 

Sure enough after a few minutes when the chip got cold the motor stopped running.  So we took voltage measurements of the board including the mcu VDD, VDDC, and batteries.  We found all voltages to their nominal values.  Then we took an oscilloscope and while the board in fail state probed the 16MHz crystal for proper operation, and we found it to be operating

as it should.  The crystal is rated at -40 to +125C temperature range.  

 

So reset the board while in freezer to see if it would response again, instructed to run motor and nothing.

 

So then we took the board out of the freezer and warm it up to room temperature, and instructed to run the motor 

and it did as expected.  So after letting it run for several hours at room temperature and charging the Lead Acid batteries

so as to have good power, we put it back to the freezer to see if it fail again.  Yes, it did.  After a few minutes in the freezer

the board fail again, motor stopped running.  So we measured the voltages on the board again and found them good again.

crystal working, but not the motor.

 

So then we try another board with same results.  Then we decided to order a couple of the TM4C123GH6PMI which is the original chip we use to developed our firmware, and replace the TM4C123BE6PMI chips on the failing boards.  after 2 days we got the replacement chips installed them, loaded the firmware and run the board at room temperature to make sure everything was sound it was at room temperature.  Then we conducted the same test as we did before and to our surprised the TM4C123GH6PMI had fail the same way as the TM4C123BE6PMI chips.

 

That spark a questions as to weather the TIVA C parts are really to TI specs.

 

Now in order to prove that it is not our board, we decided to hook the Launchpad with minimal circuit and load the same firmware we use on our board and conducted some tests.

 

1) The Room Temperature test.  We loaded the firmware then run the code and let it run for a few hours.  Found no errors

code was still running with no problems.  Launchpad was also program to report internal temperature via its uart interface to our pc, we found no internal temperature issues here.

 

2) The Freezer Temperature test.  We then put it on the freezer run the code and sure enough after a few minutes the Launch Pad had fail.  Here is the interesting part of this the crystal was found to be operational, but the board seem like it was literally frozen. No punt meant here.

 

3) Bench Temperature test.  We then took the Launch Pad back to the bench connected to the CCS 5 and started a debug session and slowly cool the Launch Pad via freezing sprays.  We were carefully not to over freeze the part below -40 C.

 

As we were doing this and seeing the temperature return by the mcu via uart, we so that as soon as the temperature pass 0 C

the PWM1 signals stopped working, the Uart message where still coming into our PC, but as soon as the temperature reached

-12 or so the UART messages stopped.  The CCS 5 Debug session had not fail though, that means the JTAG part of the chip still works at that low temperatures.  

 

UPDATE.. UPDATE..

 

4) Hot temperature test:

 

We then took our board and the Launch Pad as well and heated them up with heater as high as we could to see if the parts

fail at higher temperature as well.  To our surprise, we found that the PWM1 signals running the motor change Pulse Width

with increase of temperature after it reach +42C or so. which cause the motor to speed up as the temperature increased.  

Very disturbing.  

 

Both our board and the TIVA C Launch  Pad did the same thing.

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Thank you guys for your responses.

 

spirilis

 

Our board design around the TIVA C TM4C123BE6PMI rated for a temperature range of -40C to 85C (Industrial)

and made 22 boards for on field testing by our customer.  We initially develop the code on the TIVAC Launchpad

which uses the TM4C123GH6PMI also rated for Industrial temperature range.  

 

Customer install the boards on the field for testing and found that when temperatures were below 0C, in fact -4C

they so the boards fail to run the motor in which they were design to control.

 

So, we conducted our own test here at our place by running the board with a motor attached and run by Lead Acid Batteries

in side a freezer set to a temperature of -18C.  

 

Sure enough after a few minutes when the chip got cold the motor stopped running.  So we took voltage measurements of the board including the mcu VDD, VDDC, and batteries.  We found all voltages to their nominal values.  Then we took an oscilloscope and while the board in fail state probed the 16MHz crystal for proper operation, and we found it to be operating

as it should.  The crystal is rated at -40 to +125C temperature range.  

 

So reset the board while in freezer to see if it would response again, instructed to run motor and nothing.

 

So then we took the board out of the freezer and warm it up to room temperature, and instructed to run the motor 

and it did as expected.  So after letting it run for several hours at room temperature and charging the Lead Acid batteries

so as to have good power, we put it back to the freezer to see if it fail again.  Yes, it did.  After a few minutes in the freezer

the board fail again, motor stopped running.  So we measured the voltages on the board again and found them good again.

crystal working, but not the motor.

 

So then we try another board with same results.  Then we decided to order a couple of the TM4C123GH6PMI which is the original chip we use to developed our firmware, and replace the TM4C123BE6PMI chips on the failing boards.  after 2 days we got the replacement chips installed them, loaded the firmware and run the board at room temperature to make sure everything was sound it was at room temperature.  Then we conducted the same test as we did before and to our surprised the TM4C123GH6PMI had fail the same way as the TM4C123BE6PMI chips.

 

That spark a questions as to weather the TIVA C parts are really to TI specs.

 

Now in order to prove that it is not our board, we decided to hook the Launchpad with minimal circuit and load the same firmware we use on our board and conducted some tests.

 

1) The Room Temperature test.  We loaded the firmware then run the code and let it run for a few hours.  Found no errors

code was still running with no problems.  Launchpad was also program to report internal temperature via its uart interface to our pc, we found no internal temperature issues here.

 

2) The Freezer Temperature test.  We then put it on the freezer run the code and sure enough after a few minutes the Launch Pad had fail.  Here is the interesting part of this the crystal was found to be operational, but the board seem like it was literally frozen. No punt meant here.

 

3) Bench Temperature test.  We then took the Launch Pad back to the bench connected to the CCS 5 and started a debug session and slowly cool the Launch Pad via freezing sprays.  We were carefully not to over freeze the part below -40 C.

 

As we were doing this and seeing the temperature return by the mcu via uart, we so that as soon as the temperature pass 0 C

the PWM1 signals stopped working, the Uart message where still coming into our PC, but as soon as the temperature reached

-12 or so the UART messages stopped.  The CCS 5 Debug session had not fail though, that means the JTAG part of the chip still works at that low temperatures.  

 

UPDATE.. UPDATE..

 

4) Hot temperature test:

 

We then took our board and the Launch Pad as well and heated them up with heater as high as we could to see if the parts

fail at higher temperature as well.  To our surprise, we found that the PWM1 signals running the motor change Pulse Width

with increase of temperature after it reach +42C or so. which cause the motor to speed up as the temperature increased.  

Very disturbing.  

 

Both our board and the TIVA C Launch  Pad did the same thing.

Nice.  I might try rigging up an Energia sketch with my nRF24L01+ radio transceiver and put it outside tonight to see what happens (supposed to hit a low of 28F, not sure if that's cold enough, since it's -2C basically).

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rockets4kids

 

TI did tell us that we needed to file a Failure analysis report through our distributor 

and we have but, we just concerned that this may take weeks before any thing is done about it.

 

I requested to talk to a TI engineer expert on the ARM TIVA C parts but tech support refuse to

connect me with one of them.

 

It just mind boggling that TI would not get some one into that matter quick 

since this issue is serious issue.  The TIVA C parts, at least the ones we have tested, miserably fail to meet specs

 

on cold temperature side of things fail -4 and below just not even close to -40C, you know if it was say -36 or so 

I can take that but -4 C come on.

 

and now on the high temperature side of things +42 we started seeing failures and chips are rated to work at +85C.

 

Not good.

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I'd try to simplify the test setup before putting the blame on the MCU. From the description above, the system under test is the whole of:

- custom board or launchpad

- fairly complex firmware

- parts outside MCU

- the MCU

 

Not saying that it is your fault, but it might as well be the firmware not handling well unexpected timing differences due to faster/slower clock due to temperature change. I would run basic test programs starting with blinking LEDs and then expanding to individual peripherals. E.g. UART communication will be heavily impacted by an oscillator that drifts with temperature.

 

The operating temperature in the datasheet just means that the chip and peripherals should work under these conditions. From what I can see there's no statement on clock stability etc. relative to temperature.

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chicken,

 

great points. and by no means am I putting blame on TI, but the fact that they show little interest in helping us

out directly other than suggesting the forums make me wonder about TI.

 

Any how.

 

Here are some details about your crystal stability concerns, which we had the same concerns and even though

I did not mention this an my previous post, but we have run the firmware using the internal oscillator of the TIVA C pars

which according to datasheet the internal crystal should be +- 3% through -40 to +85 temperature range with same results.

The parts fail regardless we run it from external crystal or internal oscillator.

 

+-3% clock variance should not cause PWM or ADC to drift so bad that it causes Motor to either stop or speed up.

 

Now, we have spot tested the other components on our board and Launch Pad with Freezing spray while running to see if any other component when spot frozen cause the mention failures.

 

The only one found to cause problems when expose to low or high temperatures was the TIVA C parts.

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Agree on the frustration of getting direct support from large companies, being it TI or others.

 

Working for a large software company, I know that people are more reactive to reports that already tracked down the exact point of failure as it saves them time. Engineers typically already have their plate full with work for customers with deeper pockets and/or the phone number of the CEO.

 

That's why I try to dumb things down until it's undeniably clear where the core issue lies. In your case, toggle pins to confirm whether clock variance over temperature is inside or outside spec.

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Hello forum members

 

We have an update on the issues posted here.

 

After reading all your great suggestions and going back 

 

and trying to do as suggested, we finally after several hours

 

of debug and test we were able to ping point the trouble piece of code.

 

For the low temperature issues it turns out that our equation calculating

 

fault temperatures was off by factor of 10 as a results when the temperature

 

return back by ADC at temperatures below 0 was causing our equation to blow up

 

and trick our code that a temperature fault had occurred on the board and PWM

 

and motor needed to be shutdown.  Why we did not catch this before, was for two reasons

 

1) I am a monkey, and failed miserably to code the right equation for the temperature fault.

 

2) I fail to keep the temperature fault flag longer then a few seconds to allow me to see 

what had cause the temperature fault.  Now I set up a sticky fault to allow me to see

what had cause the temperature fault.

 

Now I am doing more freezer testing and High temperature testing just to make sure I did not guff again.

 

Thank you so much for all of you that took that time to respond and make great suggestions to try out

 

and get to a resolution.

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