REM

REM is a Yocto like buildsystem primarily intended for microcontrollers. It is based on ruby rake and therefore offers a highly flexible way of setting up projects for microcontrollers. If you know Yocto it should be easy to also learn the REM buildsystem. It consists of some features of Yocto, like recipe appending, inbuild patching and downloading software packages. Projects can be setup by only defining recipes, which describe how a specific component should be built. You can even setup your project with sources completely hosted by github! Not necessary to copy-paste software packages and libraries!

Prerequisites

• Appropriate Microcontroller toolchain (arm-none-eabi, avr, sdcc ...)
• ruby (a recent version: >= version 2.2.1)
• rake (a recent version: >= version 10.4.2)
• unzip
• git
• subversion
• simplecov (optional)

Getting started Debian/Ubuntu

• Minimal requirements
  • Debian (at least 9)
  • Ubuntu (at least 16.04)

1. Install dependencies

sudo apt install rubygems patchutils gcc-arm-none-eabi clang gcc-avr avr-libc git subversion unzip wget curl make python3 sdcc sdcc-libraries cppcheck

2. Install REM buildsystem

sudo gem install rake_embedded

3. Prepare test project

git clone https://github.com/franzflasch/rem_packages.git
git clone https://github.com/franzflasch/rem_test_project.git

4. Start build

Atmel Atmega168

rem ARCH=avr MACH=atmega168 PROJECT_FOLDER=rem_packages,rem_test_project -m -j4 package:test_project:image[hex]

STMicroelectronics STM32F3

rem ARCH=arm MACH=stm32f3 PROJECT_FOLDER=rem_packages,rem_test_project -m -j4 package:test_project:image[bin]

NORDIC Semiconductor nrf24le1_32

rem ARCH=8051 MACH=nrf24le1_32 PROJECT_FOLDER=rem_packages,rem_test_project -m -j4 package:test_project:image[hex]

Microchip PIC32MX2

rem ARCH=mips MACH=pic32mx2 PROJECT_FOLDER=rem_test_project,rem_libopenpic32,rem_packages package:test_project:image[srec]

Microchip PIC32MZ2048

rem ARCH=mips MACH=pic32mz2048 PROJECT_FOLDER=rem_test_project,rem_libopenpic32,rem_packages package:test_project:image[srec]

Native (Build Host) Linux

rem ARCH=native MACH=linux PROJECT_FOLDER=rem_test_project,rem_packages package:test_project:link

The image will end up in rem_workdir/#{arch}_#{machine}/deploy It will be either a binary or hex image, depending on what you've chosen to build.

The arguments "-m -j4" mean to build with max 4 threads simultaneously.

After the successful build you can flash the image with the right tool for your microcontroller.

Further Build examples:

Using CLANG instead of GCC

sudo apt install clang llvm lld

Be aware that certain recipes need to be patched to make it work with clang. The build-system now assumes that there is a arm-none-eabi compiler located at /opt/local/cross-tool-cortex-m4-gcc12/

STMicroelectronics STM32F3

rem ARCH=arm MACH=stm32f3 PROJECT_FOLDER=rem_packages,rem_test_project -m -j4 package:test_project:image[bin] USE_CLANG=1

Verbose output:

rem ARCH=arm MACH=stm32f3 PROJECT_FOLDER=package,test_project -m -j4 package:test_project:image[bin] VERBOSE=1

Load the hex file into an atmega168 microcontroller.

avrdude -F -cstk500v2 -P/dev/ttyUSB0 -patmega168p -Uflash:w:workdir/avr_atmega168/deploy/test_project/test_project.hex

List all available packages for this architecture:

rem ARCH="avr" MACH="atmega168" PROJECT_FOLDER=package package:list_packages

Get a list of dependencies for a particular package:

rem ARCH="avr" MACH="atmega168" PROJECT_FOLDER=package package:msglib_test:depends_chain_print

simplecov code coverage - check the codecoverage of the rem buildsystem itself

rem ARCH="arm" MACH="stm32f3" VERBOSE=1 WORKDIR=../../../../Desktop/rem_workdir PROJECT_FOLDER=package,test_project package:test_project:image[bin] SIMPLECOV=1

The output will be placed in a folder called 'coverage'

Dependency Check

There is also a little script which helps checking if there are any superfluous dependencies set:

WORKDIR=/home/user/Desktop/rem_workdir ARCH=arm MACH=stm32f3 PROJECT_FOLDER=test_project,rem_packages PACKAGE_NAME=test_project check_deps.sh

Find unused functions and auto comment them to save space

This is especially for some compilers like sdcc, as they may do not have an option to auto remove them: use it like this: comment_unused_functions_cppcheck.sh folder_to_check "folders_to_exclude_from_check_separated_with_spaces"

comment_unused_functions_cppcheck.sh . "nrf24le1_sdk_nohash/"

After the successful execution you should reinvoke the rem build command to rebuild the image. The file should be appreciably smaller if many functions were removed.

Supported microcontrollers

• Atmel Atmega168
• STMicroelectronics:
  • STM32F1
  • STM32F3
  • STM32F4
• SILABS
  • C8051FXXX
• Nordic Semiconductor
  • nrf24le1_24
  • nrf24le1_32
  • nrf24le1_48
  • nrf51822
• Microchip
  • PIC32MX2
  • PIC32MZ2048
• RISC-V
  • HiFive1