Power on behavior

Question about power
Post Reply
YahooArchive
Posts: 1463
Joined: Fri Oct 19, 2012 5:11 am

Power on behavior

Post by YahooArchive » Wed Jan 30, 2013 1:50 am

>from the help line
>I'm planning on inhibiting RESET by writing an interrupt routine along the
lines of EINT1.bas in the Interrupt folder to essentially 'do nothing'.. But
after looking at EINT1 I'm concerned!

>It looks to me as if after running EINT1 there is a potential problem handing
control back to the IDE for reprogramming? Even turning power off/on will
restart a user program again won't it?
>Or does the POR code overwrite the modified vector?

In all the NXP ARM chips there is "ROM" code in addition to Flash.

On reset this code looks at the state of P0.14 or P2.10 depending on the part.
If this pin is low, then the boot loader is launched.

If the pin is high the user code (BASIC or C) is run.

While this "ROM" code can actually be in Flash it cannot be altered in the
field.

So normally you can always reprogram the part. I say normally as there are other
code protection mechanisms, for details on those take a look at NXP's user
manuals.



Post Reply