10 years, 5 months ago.

Support for LPC812 chip

There seems to be very limited support and documentation for this chip. The 812 seems to be unique due to the switch matrix IO and I have not seen any examples on how to really use this feature with the online compiler.

There are some other little details like the external xtal is not turned on by default causing people to make patches.

It also looks like the program cannot be exported to offline compilers.

Any help would be appreciated.


Question relating to:

LPC800-MAX from NXP is an mbed enabled platform which combines the advantages of the mbed ecosystem and Arduino form factor.

It should be possible to export a generic zip archive and to uVision. A DS-5 exporter will be added in the next few weeks.

posted by Stephen Paulger 13 Nov 2013

Thanks this will be helpful. Right now I am looking at using the MBED IDE and LCPXresso which was the code red IDE.

posted by Travis Travelstead 13 Nov 2013

1 Answer

10 years, 5 months ago.

Here is more info on using the lpc812. The pinswitch matrix is more or less covered by the mbed library. You can select the pins for the mbed online compiler by using the normal convention, for example :

Serial pc(P0_4, P0_0); // tx, rx

The mbed lib default mode is to use the internal oscillator. You need patches only when you wish to use the external X-tal. Note that the LPC800 MAX board is wired to use the internal oscillator, you need to change some solder pads when you want to activate the crystal. The LPCXpresso board on the other hand has the X-tal wired. Obviously, you loose some portpins when the X-tal is needed. The X-tal has the advantage of higher accuracy. Timers will have some error when the internal oscillator is used.

Thanks, this is helpful. I did find you page which has been the most helpful so far. I also found some patch code for the external XTAL here https://mbed.org/handbook/mbed-NXP-LPC800-MAX . I figure I can cobble the switch matrix portion together with the outputs from NXP tool http://www.lpcware.com/content/tools/lpc-initializer but I would like to know what a good practice is. I apologize because at least some of the issue is my ignorance which combined with available time limits my ability to solve this on my own. Plus if somebody has done it before I would like to learn from them if possible.

Thanks again

posted by Travis Travelstead 13 Nov 2013

I have started a notebook page to help gather information similar to your wonderful page http://mbed.org/users/TravisT/notebook/lpc812-with-mbed/

posted by Travis Travelstead 13 Nov 2013