MK02 doesn't reset in VLLS1 when EXTAL is configured as input

[k-laus]

Hi,

we're working with a MK02FN64VLH10 and use the internal clocking.

In case of an error, we'll use the VLLS1 mode. While in VLLS1 mode, we'll drive a red led (led is set before VLLS1 and in VLLS1 I/O states are held). To restart the microcontroller, we'll drive the reset pin low. Then the red led is turned off (due to the reset, the default pin configuration of the led pin is input) and the microcontroller starts and works well (see: 1. Working reset ).

Now, we've some trouble when configuring the EXTAL Pin (Port A Pin 18 -> PORTA18) as input. Our "normal" resert in VLLS1 mode(drive the reset pin low) doesn't work anymore (see: 2. Don't working reset ). The red led is turned off, but the microcontroller doesn't start anymore.
To start the microcontroller again we have to turn the power supply off and on again (power on reset).
In this state we also haven't any access to the microcontroller by debugging.

The behavior is independent, wether the debugger is connected or not.
We have had a look at the signals at the reset pin and at PORTA18. There are no spikes or anything else we wouldn't expect.

1. Working reset (yellow - reset; green - PORTA18):

2. Don't working reset (yellow - reset; green - PORTA18):

Does anyone have an idea, what we could do wrong?

Thank you very much.

K-laus

[kerryzhou]

Hi K-laus,

   Please check these two points at first:

1. PTA18 is the EXTAL pin at default, if you want to use the GPIO function, please configure the PORT and change the MUX to 1.

2. Please add this code in the main function.

        if (PMC_REGSC &  PMC_REGSC_ACKISO_MASK)
        PMC_REGSC |= PMC_REGSC_ACKISO_MASK;

After checking these two points, then try again on your side.

Any updated question, please let me know!

Have a great day,
Kerry

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[k-laus]

Hello Kerry Zhou,

we have checked, that the port is configured to GPIO (MUX = 1).

Also, we have tried your code at the beginning of our main-function.

Unfortunately we still have the same behavior.

Do you have any other idea?

Thank you.

K-laus

[kerryzhou]

Hello K-laus,

   I find you said this information:

To start the microcontroller again we have to turn the power supply off and on again (power on reset).

  Do you mean, after you download the code (PTA18 GPIO input), it won't work, just need to power off and power on again, now I have a question, after you power on again, whether your code function can work normally?

  Please try two codes(With PTA18,and without PTA18) both in this condition: After download the code, power off the board, disconnect the debugger. then power on the board, whether the code function is working the same?

Have a great day,
Kerry

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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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[k-laus]

Hello Kerry Zhou,

after the controller has gone into vlls1 we want to "restart" it by the reset-pin.

We can reset it (by the reset-pin), if the PORTA18 was configured as EXTAL (default), while entering vlls1.

We can't reset it (by the reset-pin), if PORTA18 was configured as ALT1 (GPIO, Input), while entering vlls1.  

In this "mode", if we want to restart it again, we have to power off and on. Then it will work fine again.

About your question:

The code function is working the same? - yes

We only have problems, when we want to exit from vlls1 by the reset-pin (and PORTA18 is configured as input)

Have a great day,

K-laus

[k-laus]

Hello Kerry Zhou,

one more information....

It works (restart the controller by the reset-pin from vlls1 - when PORTA18 was configured as input), when we were cooling the controller, while entering vlls1.

Best regards,

K-laus