MNT Reform: Open Source Portable Computer
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LPCXpresso Support in the LPC11U/LPC13U Code Base

This codebase includes project files for NXP’s free Eclipse-based LPCXpresso IDE, which is based on the Code Red’s commercial Red Suite. The key advantage of LPXpresso -- aside from being free for binaries up to 128KB -- is that along with the IDE, you can purchase very low-cost LPCXpresso development board that include a full on-board HW debugger. The HW debugger can be ‘cut’ from the MCU half of the board, and you can then use that debugger inside the LPCXpresso IDE to program and debug any support LPC MCU, including any HW that you develop based on this code base.

Getting Started with LPCXpresso and the LPC11U/LPC13U Code Base

While teaching you how to use LPCXpresso/RedSuite or Eclipse is beyond the scope of this tutorial, this will hopefully explain some of the main issues you’ll encounter when using this code base with this IDE.

The main issue is the fact that the code base supports two different chip families with two different cores: ARM Cortex M0 for the LPC11U24/LPC11U37 and ARM Cortex M3 for the LPC1347.

If you are switching between cores, of if your project files are configured for a different core than you want to use, you’ll need to make a few changes to the project files, as detailed below ...

Switching MCUs with LPCXpresso/RedSuite

One of the unfortunate restrictions of using a common code base for the LPC11Uxx and LPC13Uxx with LPCXpresso/RedSuite is that the MCU settings are not included in the ‘target’ scope, so there’s not easy way to switch your project config between LPC11U and LPC13U configs.

You need to make some manual changes to your project if you want to switch from a Cortex M0 LPC11U part to a Cortex M3 LPC13xx part or vice versa. This guide will show you the steps necessary to make these changes inside the IDE.

Step One: Selecting your MCU

Right-click on your project name in the Project Explorer and select ‘Properties’. From there, navigate to C/C++ Build > MCU Settings and select your MCU:

  • LPC11Uxx > LPC11U24/401
  • LPC11Uxx > LPC11U37/401
  • LPC13xx (12bit ADC) > LPC1347

MCU Settings

Step Two: MCU C Settings

Next you need to update the references to the external CMSIS library and the selected core in the MCU C Settings dialogue (C/C++ Build > MCU Settings > MCU C Compiler).

NOTE: Be sure to make these changes for every Configuration in the ‘Configuration’ dropdown at the top of the dialogue box!

C Symbols

C Includes

C Target

Step Three: MCU Assembler Settings

Next change the target architecture in the assembler settings exactly the same way you did for the C settings, making sure to repeat the steps for every configuration:

C Target

Step Four: MCU Linker Settings

Finally, update the linker configuration to point to the correct libraries and to links files with the right target core:

C Target

C Target

Step Five: Clean and build your project

Your project should work with the new MCU and core now. Clean and then build the project, and see if you have any issues.