LPC812 (LPC800) issues with UART and SPI

[lpcware]

Content originally posted in LPCWare by TravisT on Tue Dec 03 15:52:21 MST 2013
Hello,

The situation is I designed a board for the LPC812 while I was waiting for them to arrive. I now have the chip and I have the board. The board is overall very simple in that it drives some basic digital signals and a UART for communication.

Out of the box I was very happy I was able to program the digital IO quickly to flash LEDs and transistors. I had no issue with the pins that were already well defined. The issue is items like the UART and SPI do not seem to be working or enabled properly. I have tried several example projects (NXP CMSIS, LPCOpen and some other third party ones) some designed for the LPC810 but using UART0 which I figured did not matter. After some time comparing initialization I am stumped. Everything seems to be fairly common between the libraries and I am not yet trying to do anything crazy.

I am guessing there is some issues with the switch matrix, initialization or the chip itself. I have done a descent amount of programming with the LPC1769, however I probably relied to heavily on the MBED library.

I am using the LPC812 so20 chip and I believe it is rev 4C. I did also try this with no luck on the LPC812 xpresso board with the same results.

The third party library is located here https://github.com/microbuilder/LPC810_CodeBase, which is very similar to the NXP CMSIS example.

I am hoping somebody else has had this issue or catch something simple that I am doing incorrect.

Thanks for any help that can be given.

[lpcware]

Content originally posted in LPCWare by TravisT on Tue Dec 10 15:37:25 MST 2013
Wow, thanks. I would agree it should be noted that is limited in what it can be switched to.

It is very unfortunate that it was the first chunk of code on my first design with the LPC812 that found this issue for me. It would of been nice to get it working on something else first and avoided some of my headache.

Thanks for taking the time to help.

[lpcware]

Content originally posted in LPCWare by cpldcpu on Tue Dec 10 14:32:23 MST 2013
I fell for the same a while ago:

http://www.lpcware.com/content/forum/pio010-pio011-open-drain-pins

NXP should really document those pins better.

[lpcware]

Content originally posted in LPCWare by TravisT on Tue Dec 10 14:19:42 MST 2013
I have figured out at least the base of my issue. I was using one of the open drain pins which does not seem to work, at least without more configuration. I jumper-ed to another free pin and used the switch matrix with successful results.

I have not fully tested the SPI communication yet, but with what I have now I should be able to move forward.

In regards to the open drain pin, will it not work as a UART pin? Do I need to do some extra configuration with the pin mode in order to utilize it? I was under the assumption it was more configurable.

Thanks

[lpcware]

Content originally posted in LPCWare by cpldcpu on Tue Dec 03 23:34:06 MST 2013
Can you post (parts of) your circuit and your code? It seems to be close to impossible to help you with just the information you provided.