K60 is continuously resetting not coming out of reset

[AnoopMathew]

We are using K60-150 MHz controller-  MK60FN1M0VLQ15 controller. However the unit is not reseting properly.

We have provided a reset IC TPS3823-25DBVR, but the device was not coming out of reset when we monitored we have noticed that the reset pin is toggling with a pulse. (the pulses has a large rise time)

Please let me know what will be the reason for the same. We tried removing the reset IC the result is same.

We have provided 10K pull up on both reset pin and EZP_CS_b

pin as well.

while probing we noticed that if we keep the scope probe on the

reset pin the device is coming out of reset after 20-30sec.

however if we remove the probe and again probe the reset pins

starts toggling.

[larryc]

You said :

"Also we made a new board, it was able to program but it was not running the code. And struck at the RTC initilization. We monitored the 32kHz crystal, it was not oscillating and then onwards we are not able to program the controller."

You send you could program the board but it was "not running the code".  If it was not running, how did it get stuck at the RTC initialization.

I would start with the basics.  How did you try to flash the board (tools, sw, etc) and what led you to assume it did not work?  Did you try running and stepping with your debugger directly from reset?

Better questions yield quicker and better answers!

Larry

[Carlos_Mendoza]

Hi Anoop Varghese,

The toggling of the reset pin is an expected behavior when the flash is not programmed, this is because on a blank device the core goes to 0x0000_0000 to fetch the initial stack pointer and 0x0000_0004 to fetch the reset vector, both of these will read 0xFFFF-FFFF which are illegal addresses causing the chip to reset and start all over again. When the chip is programmed you will find the reset pin oscillating behavior gone.

Hope it helps!

Best Regards,

Carlos Mendoza

Technical Support Engineer

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[AnoopMathew]

Hi Carlos,

thanks for your valid response,  however when we try to program we are observing the an error.

" CPU did not stop". So we are not able to program the controller.

Please suggest us what is this issue?

Also we made a new board, it was able to program but it was not running the code. And struck at the RTC initilization. We monitored the 32kHz crystal, it was not oscillating and then onwards we are not able to program the controller.

The reset pin is toggling with 50us pulses and when we try to program through IAR the " CPU did not stop". error pops up

Regards,
Anoop

[Carlos_Mendoza]

Hi Anoop Varghese,

Please take a look to the chapter 2.1.5.3 of the following document, it shows the interface connections for JTAG and Serial Wire debugging:

http://www.freescale.com/files/32bit/doc/quick_ref_guide/KQRUG.pdf

We also recommend to connect the RESET pin to a pull up resistor of 4.7k - 10k and a 0.1 µF capacitor to VSS since this pin sometimes causes troubles if it is left floating.

Please compare your connections to the one shown in the document.

Hope it helps!

Best Regards,

Carlos Mendoza

Technical Support Engineer

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Note: If this post answers your question, please click the Correct Answer button. Thank you!

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