Freeze with LPM3, but no problem with LPM2 at MSP430FR5847

Hi Yane,
To get a better understanding of your problem, can you please provide some more information? I would like to know at which supply voltage is this happening. Another questions is regarding your clock system configuration. What is your clock source for MCLK? Are you using an external crystal? If yes, which kind and which load caps are you using.

Best regards,
Tobias

Hi Tobias,

Thank you for your quick response.

 I would like to know at which supply voltage is this happening.

Supply voltage is about 3V Li-ion coin battery in the product.

For analysis a labo supply 2.5V was used also. The problems were found with both the supply.

It seemed the power source was not the problem.

Another questions is regarding your clock system configuration.

Clock system configuration was created by grace, the source code is following:

void CS_A_graceInit(void)
{

    /* USER CODE START (section: CS_A_graceInit_prologue) */
    /* User initialization code */
    /* USER CODE END (section: CS_A_graceInit_prologue) */

    /*
     * Sets the external clock source for XT1 and XT2. These variables can be used by
     * other API functions.
     *   XT1 Frequency -  32768 Hz
     *   XT2 Frequency -  0 Hz
     */
    CS_setExternalClockSource(32768, 0);

    /*
     * Start Low Frequency crystal in low frequency mode
     */
    CS_LFXTStartWithTimeout(LFXTDRIVE_3, 100000);

    /*
     * Setting MCLK source from CS_DCOCLK_SELECT with the divider of CS_CLOCK_DIVIDER_1.
     */
    CS_clockSignalInit(CS_MCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1);

    /*
     * Setting SMCLK source from CS_DCOCLK_SELECT with the divider of CS_CLOCK_DIVIDER_1.
     */
    CS_clockSignalInit(CS_SMCLK, CS_DCOCLK_SELECT, CS_CLOCK_DIVIDER_1);

    /*
     * Setting ACLK source from CS_LFXTCLK_SELECT with the divider of CS_CLOCK_DIVIDER_1.
     */
    CS_clockSignalInit(CS_ACLK, CS_LFXTCLK_SELECT, CS_CLOCK_DIVIDER_1);

    /*
     * Set DCO frequency to 1000000 Hz
     */
    CS_setDCOFreq(CS_DCORSEL_0, CS_DCOFSEL_0);

    /*
     * Clears all oscillator fault flags including global oscillator fault flag
     * before switching clock sources
     */
    CS_clearAllOscFlagsWithTimeout(100000);

    /*
     * MCLK clock request enable. Setting this enables conditional module requests for MCLK
     */
    CS_disableClockRequest(CS_MCLK);

    /*
     * SMCLK clock request enable. Setting this enables conditional module requests for SMCLK
     */
    CS_disableClockRequest(CS_SMCLK);

    /*
     * ACLK clock request enable. Setting this enables conditional module requests for ACLK
     */
    CS_disableClockRequest(CS_ACLK);

    /* USER CODE START (section: CS_A_graceInit_epilogue) */
    /* User code */
    /* USER CODE END (section: CS_A_graceInit_epilogue) */
}

What is your clock source for MCLK? 

MCLK clock source is DCOCLK.

Are you using an external crystal? If yes, which kind and which load caps are you using.

Yes we are using an external crystal. 

And the load caps are 22pF.

The xtal circuit passed the test of their xtal supplier.

Thank you and Best regards,

Yojiro

Hi Yojiro,
Thanks for your additional information.

About the power source, if in case that you’re using the recommended caps on each DVcc/DVss pins I think as well, the power source is fine. My expectations is as well, that AVcc is at the same voltage level as DVcc?!

You’re clock system configuration looks as well ok.

So seams that my first ideas wasn’t forcing your issue. Can you please let us know what your wakeup event is and how often is occurs? Just roughly, like once a second… Another questions is about your PCB. Are you using a Launch Pad or one of your own layouts?

Best regards,
Tobias

Hi Tobias,

Thank you for your reply.

I would ask you to back to the original discussion.

Could you please explain the freeze issue by LPM3 and LPM2 difference.

 

 

 

---

Replies to your questions:

 

About the power source, if in case that you’re using the recommended caps on each DVcc/DVss pins I think as well, the power source is fine.

Production: NG: 1uF ceramic each for AVcc and DVcc.

Analysis: NG: 1uF + 1uF each for AVcc and DVcc.

Analysis: NG: 1uF + 100nF each for AVcc and DVcc.

 

 

My expectations is as well, that AVcc is at the same voltage level as DVcc?!

 I believe so.

A single LDO output divides in two, go through a 0 ohm and 1uF, and reach DVcc and AVcc. You will be receive the PCB layout via TI japan.

  

Can you please let us know what your wakeup event is and how often is occurs?

Wakeup event is GPIO interrupts. 3 input pins like switch press.

Once per various trials. Sometimes 1 out of 1 trial. Sometimes 1 out of 300 trials. Totally we see problems 20 times.

 

Just roughly, like once a second… Another questions is about your PCB. Are you using a Launch Pad or one of your own layouts?

 Own layout. We are trying to send it to you via TI japan.

 

Best regards,

Yojiro

Hi Tobias,

Thank you for your reply.

I would ask you to back to the original discussion.

Could you please explain the freeze issue by LPM3 and LPM2 difference.

 

 

---

Replies to your questions:

 

About the power source, if in case that you’re using the recommended caps on each DVcc/DVss pins I think as well, the power source is fine.

Production: NG: 1uF ceramic each for AVcc and DVcc.

Analysis: NG: 1uF + 1uF each for AVcc and DVcc.

Analysis: NG: 1uF + 100nF each for AVcc and DVcc.

My expectations is as well, that AVcc is at the same voltage level as DVcc?!

I believe so.

A single LDO output divides in two, go through a 0 ohm and 1uF, and reach DVcc and AVcc. You will be receive the PCB layout via TI japan.

 

Can you please let us know what your wakeup event is and how often is occurs?

Wakeup event is GPIO interrupts. 3 input pins like switch press.

Once per various trials. Sometimes 1 out of 1 trial. Sometimes 1 out of 300 trials. Totally we see problems 20 times.

 

Just roughly, like once a second… Another questions is about your PCB. Are you using a Launch Pad or one of your own layouts?

Own layout. We are trying to send it to you via TI japan.

 

Best regards,

Yojiro

Hi Yojiro,
Thanks again for sharing further information about your problem. I needed this information to get a closer view at this problem.

Seams that you’re already in production, so I would like to ask you to contact your local FAE team and ask them to open a quality case about this problem or you can send me a personal message with your contact information and I will contact you directly. This will allow us to identify and to handle this problem much faster.

Thanks and best regards,
Tobias