LPC183x TFGA100 JTAG/SWD not working

[lpcware]

Content originally posted in LPCWare by jones_hsu on Fri May 17 11:48:15 MST 2013

Hi Sir, 

  We got issue from this week which JTAG/SWD lost link with the chip,

   some condition as Below :

  1. Keil 4.5 + Jlink , and SPIFI mode.

  2. the chip is LPC1830BGA100--, and LPC1837BGA100-A

    there are 5 pcs of 10 PCB lost link after a week working.

 3, base On openplatform 1.02 , we just add some GPIO and timer control ..

   no CRP register touch , no AES touch ..

  4. when lost JLINK, the chip is working normal , SPIFI interface working.

     only JTAG lost link, and can't update .

 5. when lost Jlink, P2.7 ISP pin control is not working.

6. When lost Jlink, we try to configure boot mode from USB1 ,

    and it's working, i can install LPC USBD driver.

6. we try to replace SPI flash ( W25Q32BV) , and Jtag still not working.

   even remove SPI Flash , Jlink still not working.

7. those PCB are working normal few days , and working by un-know reason.

any suggestion for us ?

tks !

 BR,Jones 

[lpcware]

Content originally posted in LPCWare by jones_hsu on Sun May 26 08:06:33 MST 2013

Hi Bavarian,

  tks for the reply.

   We will follow the suggest to implement Diode to protect the signal ..

 tks !

 BR,Jones 

[lpcware]

Content originally posted in LPCWare by bavarian on Fri May 24 09:39:27 MST 2013

Dear Jones,

let me summarize the problem in my words:

1) You had boards which worked fine, you were able to work with the JTAG debugger.

2) You worked with these boards for a few days and then you lost the JTAG connection
   --> Question:  how did you "work" with the boards? Developed software, programmed, erased, power-on/off, something like this?

3) You tested the chip in USB boot mode and it was working.
   --> Comment: same could be tested with UART0 bootmode, this would enable to work with the FlashMagic tool for programming of the SPIFI memory:
        http://www.flashmagictool.com/

4) Your conclusion is, that the JTAG port is not longer working.

Here is my conclusion:

The problems sounds familiar. It has been seen on development boards from Hitex and KEIL first. These boards were powered on/off and connected to debuggers all the time. And then we had the same problem you described.

What we found out is, that the electrical potential difference between the power supply of the board and the power supply of the debugger potential equalization and therefore to a high current on JTAG port pins. We analyzed one of the failing chips and saw a physical damage on the internal structure which prevented the JTAG port to work correctly. We test our chips against EMV according to our spec, but this situation seems to be out of the spec.

Our solution for the development boards is therefore a protection diode on all JTAG signals. KEIL for example delivers a small add-on connector for the 20-pin JTAG header which contains these protection diodes. In the attachment you see a possible implementation. You could also use 4 single diodes connected to every pin of the JTAG.

If you need the JTAG port in your end product as well (e.g. for firmware upgrades in the field, then I recommend these diodes as well. This applies to the use case where the MCU board is powered with a switched power supply and the debugger is powered from a different switched power supply.

I hope that this info helps you to solve this problem, at least on the development boards it has been solved this way.

Best regards,

NXP Technical Support Team

[lpcware]

Content originally posted in LPCWare by bavarian on Fri May 24 09:38:07 MST 2013

Dear Jones,

let me summarize the problem in my words:

1) You had boards which worked fine, you were able to work with the JTAG debugger.

2) You worked with these boards for a few days and then you lost the JTAG connection
   --> Question:  how did you "work" with the boards? Developed software, programmed, erased, power-on/off, something like this?

3) You tested the chip in USB boot mode and it was working.
   --> Comment: same could be tested with UART0 bootmode, this would enable to work with the FlashMagic tool for programming of the SPIFI memory:
        http://www.flashmagictool.com/

4) Your conclusion is, that the JTAG port is not longer working.

Here is my conclusion:

The problems sounds familiar. It has been seen on development boards from Hitex and KEIL first. These boards were powered on/off and connected to debuggers all the time. And then we had the same problem you described.

What we found out is, that the electrical potential difference between the power supply of the board and the power supply of the debugger potential equalization and therefore to a high current on JTAG port pins. We analyzed one of the failing chips and saw a physical damage on the internal structure which prevented the JTAG port to work correctly. We test our chips against EMV according to our spec, but this situation seems to be out of the spec.

Our solution for the development boards is therefore a protection diode on all JTAG signals. KEIL for example delivers a small add-on connector for the 20-pin JTAG header which contains these protection diodes. In the attachment you see a possible implementation. You could also use 4 single diodes connected to every pin of the JTAG.

If you need the JTAG port in your end product as well (e.g. for firmware upgrades in the field, then I recommend these diodes as well. This applies to the use case where the MCU board is powered with a switched power supply and the debugger is powered from a different switched power supply.

I hope that this info helps you to solve this problem, at least on the development boards it has been solved this way.

Best regards,

NXP Technical Support Team