I'm using NXP microcontrollers since the LPC2106 and always appreciated the excellent user manuals. I managed to convince my former employer to base new hardware designs on LPC controllers rather than the Renesas parts they used at the time I joined the company. Part of the advantages I mentioned was the excellent documentation and full openness of
compiler and hardware. Long time ago (200x years). At the time I had a close look at alternatives (ST microelectronics, Atmel, Analog Devices) but none satisfied me.
Now in the year 2017 I want to get started with LPC546xx and also LPC541xx but find myself looking at alternatives again. Not just for knowing for fun what other manufacturers provide, but as a real alternative. And YES, Analog Device's CM4xx caught my interest...
Why? Why would a loyal user commit 'treason' and take all the additional work to get used to a quite different device?
Because he has a notion of freedom: he uses his own libraries and nothing but his own libraries. And NXP tries to put a 'foot in the door' to HIS code running on the LPCs. By urging him into using a closed source library function to switch the core voltage of the LPC54xxx. That is an absolutely crucial part the seems to interact with the PLL, so it's not some fancy add-on he can opt out, but something that's needed for every serious firmware. An underclocked LPC54xxx is of not much use, but that seems the consequence of purely open firmwar. FOUL by NXP!
I have no problem with ROM-API routines (I use sometimes on LPC800) which I can opt out, whenever I have concerns.
But not documenting the core voltage register interface is something very different.
Maybe, no user has explicitely made a requested, so I do it here:
NXP, please do fully document the PLL and the voltage settings required for running the core at full speed and do not urge me - your customer - to use some library 'xy' to do that. And please do it quickly. I have to do my job in a limited amount of
time and I'm not able to wait.
This issue is related to this question ('assumed answered' haha - NO! It is not answered!)
So I really hope, a responsible person takes action at NXP, quickly.
Or better, prove me wrong and show me, where to find the information, which should have been in the user manual in the first place...