I've designed a PCB that uses the MK20DX256VLH7. Upon first power-up, the microcontroller appears dead. No 16MHz XTAL oscillation, and the DX256's RESET pin is held asserted. Supply voltage is steady at +3.3V. AT this stage, I've not attached any other devices to the DX256, other than a USB connector.
What issues could be causing the part to be stalled like this? I'm very perplexed at this point.
Many thanks, in advance!
Solved! Go to Solution.
Hi Gary Kitten,
Actually, to a new chip without program, your phenomena is normal.
16MHZ external oscillator is not oscillating, it is because you didn't enable the OSC in the chip with program.
To a new chip, if you add 4.7K to 10k pullup resistor in the RESET_b pin, and connect a 100nf capacitor to ground, the reset pin should have the oscillator wave, you can check it through the oscilloscope.
You can create a sample project, to check whether your chip can download program.
After the chip have programed, it will work normally.
Wish it helps you!
Have a great day,
Jingjing
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Hi Gary Kitten,
Actually, to a new chip without program, your phenomena is normal.
16MHZ external oscillator is not oscillating, it is because you didn't enable the OSC in the chip with program.
To a new chip, if you add 4.7K to 10k pullup resistor in the RESET_b pin, and connect a 100nf capacitor to ground, the reset pin should have the oscillator wave, you can check it through the oscilloscope.
You can create a sample project, to check whether your chip can download program.
After the chip have programed, it will work normally.
Wish it helps you!
Have a great day,
Jingjing
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
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