Is this good news for NXP lpc23/24xx users..?
lpc2000 mailing list – lpc speed problem
In short – there is some issue with MAM (Memory Acceleration Module) in LPC23/24xx. If microcontroller works with high frequency clock (max is 72MHz), the MAM is enabled and there is more then 32KB of code, it may work unstable. Of course when MAM is disabled everything works just perfect. Funny thing is that same code may work perfect on another lpc microcontroller or even on the same after reflash. Same thing with frequency – you may find some information about solving MAM problem with changing frequency below 60MHz. There are also some posts about MAM problems when code is bigger then 32KB, but I think problem is related with code location, not size.
Issue may be also connected with PLL problems in lpc23xx family.
Anyway – I’m quite surprised that NXP (if guy is really from NXP…) noticed this bug so late, but better late then never. It’s hard to belive that lpc210x family has same bug (has NXP been selling it for more then a year..?).
Workaround proposition sounds like some voodoo magic – insert some NOPs and limit frequency. I would add “pray” :-).
After small reprimand I have to say that their microcontrollers even without MAM are quite fast – 72MHz is very nice frequency in ARM7. The thing is that with acceleration enabled it works even 4-5 times faster.
It’s very good that NXP finally admitted that problem exist. I hope new errata, with more precisely explanation of this bug, will be available soon.
Here is some interesting posts about MAM problems in lpc23xx family:
Investigation of LPC23xx MAM Issues – lpc2000 mailing list discussion.
