We've done a custom board with MK60DN512ZVLQ10 ( 144 pin LQFP version ), mask set 4N30D installed.
Mask set 4N30D should be the INITIAL production mask set , so really close to the definitive one ...
However, we've seen a problem when powering the 3,3 V supply with a ramp time less of 2 ms ( something that could happen for example if u're using the micro for a USB device , but not only in this case ) : the microcontroller simply doesn't reset itself .
We've also tried to add an external reset generator ( like MAX809 ) but nothing : if 3,3 V supply is too "fast" the micro doesn't start. The polite thing is that if we , after power up event ( even 2 ms after ) , reset the part by an external reset switch, the
After struggling our minds for some days with this problem, at the end we've tried to install the very same pcb a PK60N512VLQ10 with mask code 0M33Z ( the initial mask set !!! ) and , magically, problem disappeared !!!
So, our conclusion is that on mask set 4N30D there is this very annoying problem !!!
( probably the problem it is related to the POR module and / or reset logic )