libhal-lpc40

libhal platform library for the lpc40 series of microcontrollers by NXP.

📚 Software APIs & Usage

To learn about the available drivers and APIs see the Doxygen documentation page or look at the include/libhal-lpc40 directory.

To see how each driver is used see the demos/ directory.

🧰 Setup

Following the 🚀 Getting Started instructions.

📡 Installing Profiles

Profiles define which platform you mean to build your project against. These profiles are needed for code and demos in this repo and for applications that wish to execute on an lpc40 device.

conan config install -sf conan/profiles/ -tf profiles https://github.com/libhal/libhal-armcortex.git
conan config install -sf conan/profiles/ -tf profiles https://github.com/libhal/libhal-lpc40.git

Note that running these functions is safe. THey simply overwrite the old files with the latest files. So running this for libhal-armcortex between this and other platform libraries is fine.

🏗️ Building Demos

To build demos, start at the root of the repo and execute the following command:

conan build demos -pr lpc4078 -s build_type=Debug

This will build the demos for the lpc4078 microcontroller in Debug mode. Replace lpc4078 with any of the other profiles. Available profiles are:

• lpc4072
• lpc4074
• lpc4076
• lpc4078
• lpc4088

💾 Flashing/Programming

There are a few ways to flash an LPC40 series MCU. The recommended methods are via serial UART or using a debugger JTAG/SWD.

Using Serial/UART over nxpprog

nxpprog is a script for programming and flashing LPC40 series chips over serial/UART. Using it will require a USB to serial/uart adaptor.

See the README on nxpprog, for details on how to use NXPPROG.

To install nxpprog:

python3 -m pip install -U nxpprog

To flash command is:

nxpprog --control --binary demos/lpc4078/blinker.elf.bin --device /dev/tty.usbserial-10

• Replace demos/lpc4078/blinker.elf.bin with the path to the binary you'd like to flash.
• Replace /dev/tty.usbserial-10 with the path to your serial port on your machine.
  • Don't know which serial port to use? Use this guide from the MATLAB docs to your port for your operating system. Simply ignore that its made for Arduino, this guide will work for any serial USB device: Find Arduino Port on Windows, Mac, and Linux

Using JTAG/SWD over PyOCD

PyOCD is a debugging interface for programming and also debugging ARM Cortex M processor devices over JTAG and SWD.

This will require a JTAG or SWD debugger. The recommended debugger for the LPC40 series of devices is the STLink v2 (cheap variants can be found on Amazon).

See PyOCD Installation Page for installation details.

For reference the flashing command is:

pyocd flash --target lpc4088 lpc4078_blinker.elf.bin

Note that target lpc4088 works for all lpc40 series microcontrollers.

📦 Adding libhal-lpc40 to your project

This section assumes you are using the libhal-starter project.

Make sure to add the following options and default options to your app's ConanFile class:

    options = {"platform": ["ANY"]}
    default_options = {"platform": "unspecified"}

Add the following to your requirements() method:

    def requirements(self):
        if str(self.options.platform).startswith("lpc40"):
            self.requires("libhal-lpc40/[^2.1.5]")

The version number can be changed to whatever is appropriate for your application. If you don't know, using the latest is usually a good choice.

The CMake from the starter project will already be ready to support the new platform library. No change needed.

To perform a test build simple run conan build as is done above with the desired target platform profile.

🏁 Startup & Initialization

The initialize_processor() function for targets lpc4072, lpc4074 and lpc4076 should do the following:

#include <libhal-armcortex/startup.hpp>

hal::status initialize_processor()
{
  hal::cortex_m::initialize_data_section();

  return hal::success();
}

The initialize_processor() function for targets lpc4078, lpc4088:

#include <libhal-armcortex/startup.hpp>
#include <libhal-armcortex/system_control.hpp>

hal::status initialize_processor()
{
  hal::cortex_m::initialize_data_section();
  hal::cortex_m::initialize_floating_point_unit();

  return hal::success();
}

🏎️ Setting Clock Speed

To setting the CPU clock speed to the maximum of 120MHz, include the line below, with the rest of the includes:

#include <libhal-lpc40/clock.hpp>

Next run the following command but replace 12.0_MHz with the crystal oscillator frequency connected to the microcontroller. This command REQUIRES that there be a crystal oscillator attached to the microcontroller. Calling this without the oscillator will cause the device to freeze as it will attempt to use a clock that does not exist.

hal::lpc40::clock::maximum(12.0_MHz);

🕰️ Detailed Clock Tree Control

Coming soon...

🔎 On Chip Software Debugging

Using PyOCD (✅ RECOMMENDED)

In one terminal:

pyocd gdbserver --target=lpc4088 --persist

In another terminal:

arm-none-eabi-gdb demos/build/lpc4078/blinker.elf -ex "target remote :3333"

Replace demos/build/lpc4078/blinker.elf with the path to the elf file you'd like to use for the debugging session.

Using OpenOCD

Coming soon... (its more complicated)

👥 Contributing

See CONTRIBUTING.md for details.

License

Apache 2.0; see LICENSE for details.

Disclaimer

This project is not an official Google project. It is not supported by Google and Google specifically disclaims all warranties as to its quality, merchantability, or fitness for a particular purpose.