https://community.nxp.com/t5/Kinetis-Microcontrollers/MK12DX256VLK5-POR-problem/m-p/1783983#M65894 <P>Never mind, I found the problem. PTA4 (NMI) was being used as an input from another IC, and the pin was low on power up, causing an NMI interrupt. I set last word in the CFM PROT to&nbsp;0xfffff9fe to disable NMI and EZPORT, it was&nbsp;0xfffffffe.</P><P>The board now boots on power up.</P> Mon, 08 Jan 2024 00:56:54 GMT larrydemuth 2024-01-08T00:56:54Z https://community.nxp.com/t5/Kinetis-Microcontrollers/MK12DX256VLK5-POR-problem/m-p/1783815#M65881 <P>I'm using the above micro and it doesn't seem to come out of reset on a power up. I can load and debug code using JTAG (JTAG reset works). But when I power cycle the board the micro seems stuck in reset.&nbsp;The board has a reset button connected to RESET_b and this will reset the micro and everything is fine. What would cause the micro to not come out of POR on power up?</P><P>I've been using other Kinetis micros for many (many) years and never had this problem. I'm stumped!</P><P>Vcc = 2.9V so should be high enough.</P> Fri, 05 Jan 2024 21:31:17 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/MK12DX256VLK5-POR-problem/m-p/1783815#M65881 larrydemuth 2024-01-05T21:31:17Z https://community.nxp.com/t5/Kinetis-Microcontrollers/MK12DX256VLK5-POR-problem/m-p/1783983#M65894 <P>Never mind, I found the problem. PTA4 (NMI) was being used as an input from another IC, and the pin was low on power up, causing an NMI interrupt. I set last word in the CFM PROT to&nbsp;0xfffff9fe to disable NMI and EZPORT, it was&nbsp;0xfffffffe.</P><P>The board now boots on power up.</P> Mon, 08 Jan 2024 00:56:54 GMT https://community.nxp.com/t5/Kinetis-Microcontrollers/MK12DX256VLK5-POR-problem/m-p/1783983#M65894 larrydemuth 2024-01-08T00:56:54Z