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MSP430F2274 - BCL13

nixw
Prodigy 40 points

I believe one of our products is susceptible to bug BCL13.  The solution we are trialling at the moment is a 2.93V reset monitor IC placed on the reset pin.  Has anyone else come across this problem? and if so how did you fix it?

The main symptom of the problem is that after a power reset the IC is frozen and the external crystal is not oscillating.  We believe this is because the DCO did not start and therefore the program cannot run to the point where the crystal is started.

 

BCL13 - Bug description
When subject to very slow VCC rise times, the device may enter into a state where the DCO does
not oscillate. No JTAG access or program execution is possible, and the device remains in a reset
state until the supply voltage is disconnected.
Workaround:
Apply a VCC power-on ramp ≥ 10 V/second under all power-on/power-cycle scenarios.

  • 0
    Prodigy 40 points

    I've just noticed that this chip revision is ment to be fixed (Rev. G).  The behaviour seems to show otherwise.  I hope someone can help.

  • 0 in reply to nixw
    TI__Mastermind 24490 points

    Hi,

    So, to clarify, you are using a rev G chip and still observing the same problem? If so we have to consider other possibilities.

    Are you holding the device in RST until you reach a stable Vcc?
    Are you ramping the DCO to a high frequency at the beginning of your code?

    You should take the blinking LED code and perform some ramp tests to clarify... it will be a simple indicator.

  • 0 in reply to Brandon08
    Prodigy 40 points

    The DCO frequency is being changed in the first 10 lines of code, could this be the problem?

    BCSCTL3 = 0; // The effective capacitance seen by the LFXT1 crystal is set to 1pF

    BCSCTL2 = 0;

    DCOCTL = DCO2; // DCO = 4, DCO2 = 0x80

    Cheers Nick

  • 0 in reply to nixw
    TI__Mastermind 24490 points

    nixw said:

    The DCO frequency is being changed in the first 10 lines of code, could this be the problem?

    BCSCTL3 = 0; // The effective capacitance seen by the LFXT1 crystal is set to 1pF

    BCSCTL2 = 0;

    DCOCTL = DCO2; // DCO = 4, DCO2 = 0x80

    Cheers Nick

     

    Nick,

    It depends. What is the device Vcc when you ramp up your DCO's operating frequency? Make sure that you honor figure 1 (pg 23) of the datasheet: http://focus.ti.com/lit/ds/symlink/msp430f2274.pdf it is a Vcc vs frequency relation. If you ramp the DCO to a frequency higher than what is allowable by the device Vcc at that time, then the spec is violated and the PC could jump into the weeds and execute unwanted instructions. This could be a cause of what you see. I still think the best way to find out what is happening is to use the blinking LED code (from www.ti.com/msp430codeexamples) and do some ramp tests to see if the device fails with that simple code.

  • 0 in reply to Brandon08
    Prodigy 40 points

    Ok, I've added a 1s delay before the DCO frequency is set and this seems to have fixed the problem.  Thanks Brandon!

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