LPC4337: CRP on different FlashBanks

[lpcware]

Content originally posted in LPCWare by GH on Wed Apr 30 06:29:26 MST 2014
Hi,

i'm working with a LPC4337 running code on both flash banks.

The user manual "UM10503.pdf" notes on page 65 that there are individual CRP patterns for flash bank A and B.

Would it have any effect to program CRP2 or CRP3 on flash bank A and keeping the CRP on flash bank B empty, when I got valid user code on flash bank A?

Regards,
GH

[lpcware]

Content originally posted in LPCWare by MarcVonWindscooting on Thu May 01 16:45:17 MST 2014
No - if you expect an 'effect' from keeping CRP on flash bank B empty, while setting it on A.
Yes - if you consider CRP activation the 'effect'.
The CRP level of the active bank - A in your case - is applied to both banks, regardless of the CRP of the 'inactive' bank.

I would not put CRP3 into bank B because you can activate that one accidentally (command 'S' - set active bank) and reset.
Or maybe just by erasing bank A and resetting! If B containes a valid checksum and was not the active bank, just because A contained a valid checksum (and is checked first), then B will be the active one after RESET and B's CRP level in effect. Then pray, that the code of bank B can 'reinvoke ISP'. Probably it can't because that was bank A's duty  :p

Don't use CRP3 until you're absolutely sure what you're doing and you're absolutely sure that you can call reinvokeISP reliably from your program (i.e. your program doesn't crash). And probably, you should be absolutely sure about not resetting or powercycling at the wrong moment...
Use CRP1 or CRP2 2 for experimenting.

EDIT: and of course, you should use 'mxli' to easily change/observe CRP levels  :bigsmile: