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[MQX4.1] K20D50M Problem Exiting VLPR mode

Question asked by Hui Shao on Jan 22, 2016
Latest reply on Feb 16, 2016 by Hui Shao



My board is based on MK20DX128VFM5 and powered my MQX4.1.1.


Testing low power mode using VLPR by following demo code from Freescale_MQX_4_1\mqx\examples\lowpower. What I can see is the current consumption is decreased by 20mA on entering VLPR mode. But I can't get it back to RUN mode by using MQX APIs in the demo code. Here are what I used:


enter VLPR:




_lpm_set_operation_mode (LPM_OPERATION_MODE_WAIT);


exit  VLPR:

_lpm_set_operation_mode (LPM_OPERATION_MODE_RUN);



THe code above crashed in API _lpm_set_clock_configuration(BSP_CLOCK_CONFIGURATION_DEFAULT), what is the reason for it?


How can I verify the ARM core is running at 4MHz?


Another question is, since my application enters VLPR mode immediately  after power on, the IAR used can't JTAG it to load a new code in because VLPR prevents from FLASH programming. Any solution to it?