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How to disable NMI on MKL02Z32?

Question asked by Aron Papp on Jan 28, 2018
Latest reply on Jan 29, 2018 by Kerry Zhou

Hello!

 

We are using a MKL02Z32CAF4R MCU. The programming is done in MCUExpresso, and after generating the .axf file, we use openocd to download it to the MCU through an LPC-Link2 (direct download from MCUExpresso did not work).

 

In our circuit a sensor is connected to the NMI_b pin, which is pulling it down to GND. The official guide (https://community.nxp.com/servlet/JiveServlet/download/498526-1-290989/KL02_NMI.pdf) advises to change the content of the Flash configuration in the "startup_*.c" file. We made the update, but the value of the FOPT Byte did not change in the FTFA, thus had no impact on the boot process. (Change in startup_mkl02z4.c highlighted with red)

 

__attribute__ ((used,section(".FlashConfig"))) const struct { unsigned int word1; unsigned int word2; unsigned int word3; unsigned int word4; } Flash_Config = {0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFBFE};

 

openocd also complains about the checksum, but it confirms to change the register on the desired address (0x40D):

Error: checksum mismatch - attempting binary compare
diff 0 address 0x0000040d. Was 0xff instead of 0xfb

Thanks for your help,

Aron

 

UPDATE:

We tired to program the MCU via Keil uVision, and using the LPCLink2 programmer after flashing the verify was OK, and the FOPT was updated to 251 (0xFB). I can confirm, it works for both JLINK and CMSIS firmawares.

The failing command for the openocd programming:

openocd -f /usr/share/openocd/scripts/interface/cmsis-dap.cfg -f /usr/share/openocd/scripts/target/klx.cfg -c "init" -c "kinetis mdm halt" -c "program MKL02Z32CAF4R.axf verify reset exit"

If we find the correct parameters I will let you know. 

 

UPDATE 2:

With the following command one can enable openocd to write the protected memory area:

-c "kinetis fcf_source write"

You can also write for example 0xFB to FOPT directly with the following:

-c "kinetis fopt 0xFB"

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