Now, I'm not familiar with the specific MCU you're using, but shouldn't there be some specific termination on nEA? That's a pin that determines whether the program store is internal or external ... and ... you're driving nPS? Isn't that an output that tells external program memory to drive the data bus? You need to discuss these details, however minor and insignificant they seem. No, you're not using external memory, but the schematic doesn't look complete. If you're driving RESET, shouldn't you have some circuitry to reset the MCU at Power-On? Shouldn't you be doing something to protect it from what happens on nPS during the interval between when the oscillator starts and when you finally get control of the nPS pin?

What are you doing with these matters? These are not just petty annoyances that you can ignore because they don't seem relevant. Erik (sic) [it was Per, I believe] has pointed out that you seem to have no control of RESET. Have you considered the risks of letting RESET do what it wants during the power-on and power-off transient?

[edit] BTW, App-notes are notorious for incompleteness and failure to work properly.[/edit]

RE