Hi Thiago rodrigues,
What the project you have tested? LPC111xDMXslave.eww in folder: C:\nxp\lighting\backup\DMX512_RDM_SDK_v1.0\LPC111xSlave?
I also simply test it on my LPC1115 board, and debug it. Because I don't have the application's board, then I simply test it with the lpcxpress 1115 board, this board have the on board CMSIS DAP debugger.
This is my debug result:

Then my on board P0.7 can be pull low, my red led is on.
So, I think you'd better to find a debugger to test it on your side, otherwise, it is not easy to find the problem on your own designed board.
If you are using the LPC1112, you also need to modify the .icf file, change the ROM end address, because LPC1112 just have 16KB, but LPC1114 have 48KB.
The project chip you also need to change it to your own chip, this is my example:


You can find a debugger and try it again.
Any updated information, please let me know.
Have a great day,
Kerry
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------