| ../ | ||
| CHANGELOG.txt | 493363 | Dec 29 23:46:53 2024 |
| COPYING | 1348 | Jan 7 15:53:36 2024 |
| README.md | 20496 | Dec 28 15:55:31 2024 |
| README.txt | 17411 | Dec 28 15:55:31 2024 |
| boot/ | 512 | Nov 2 12:21:53 2023 |
| bootkernel/ | 512 | Dec 28 15:55:31 2024 |
| doc/ | 1024 | Dec 28 15:55:31 2024 |
| examples/ | 512 | Jan 23 09:38:03 2024 |
| extensions/ | 512 | May 8 12:01:15 2024 |
| include/ | 1024 | Dec 28 15:55:31 2024 |
| scripts/ | 512 | Apr 26 11:37:11 2024 |
| thinservers/ | 512 | Jan 7 01:11:30 2024 |
| toolchain/ | 512 | Dec 7 17:07:02 2023 |
This framework supports Linux on several single board microcomputers. The goal of the MuntsOS project is to deliver a turnkey, RAM resident Linux operating system for very low cost single board microcomputers. With MuntsOS installed, such microcomputers can treated as components, as Linux microcontrollers, and integrated into other projects just like traditional single chip microcontrollers.
Instructions for installing the MuntsOS cross-toolchain development environment onto a host computer are found in Application Note #1 and Application Note #2. Or just download and run one of the following quick setup scripts:
setup-debianInstructions for installing MuntsOS to a target computer are found in Application Note #3 and Application Note #15.
The documentation for MuntsOS (mostly application notes) is available online at:
http://git.munts.com/muntsos/doc
MuntsOS is a stripped down Linux distribution that includes a small compressed root file system within the kernel image binary itself. At boot time the root file system is unpacked into RAM and thereafter the system runs entirely in RAM.
Each kernel release tarball contains a kernel image file (.img), which may be common to several different microcomputer boards, and one or more device tree files (.dtb) that are specific to particular microcomputer boards. Some kernel release tarballs also contain one or more device tree overlay files (.dtbo) that can make small changes to the device tree at boot time.
Prebuilt MuntsOS kernel release tarballs are available at:
http://repo.munts.com/muntsos/kernels
The MuntsOS root file system can be extended at boot time using any of three mechanisms:
First, if /boot/tarballs exists, any gzip'ed tarball files (.tgz) in it will be extracted on top of the root file system. Typically you would use this mechanism for customized /etc/passwd, .ssh/authorized_keys, and similiar system configuration files.
Secondly, if /boot/packages exists, any Debian package files (.deb) in it will be installed into the root file system. Note that packages from the Debian project will probably not work; they must be built specifically for MuntsOS. The startup script that installs .deb packages also installs .rpm and .nupkg packages.
The GPIO Server extension package demonstrates how to build a Debian package that adds application specific software to MuntsOS.
Thirdly, the system startup script /etc/rc can be configured via a kernel command line option to search for a subdirectory called autoexec.d in various places, such as SD card, USB flash drive, USB CD-ROM or NFS mount. If an autoexec.d subdirectory is found, each executable program or script in it will be executed when the system boots.
The idea is to build a MuntsOS kernel (which takes a long time) once and install it to the target platform. Then application specific software can be built after the fact and installed as tarball files in /boot/tarballs; Debian, RPM, and NuGet package files in /boot/packages; or executable programs and scripts in /boot/autoexec.d.
Prebuilt MuntsOS extension packages are available at:
http://repo.munts.com/muntsos/extensions
The Thin Server is a system design pattern that is little more than a network interface for a single I/O device. Ideally, a Thin Server will be built from a cheap and ubiquitous network microcomputer like the Raspberry Pi. The software must be easy to install from a user's PC or Mac without requiring any special programming tools. It must be able to run headless, administered via the network. It must be able to survive without orderly shutdowns, and must not write much to flash media. It must provide a network based API (Application Programming Interface) using HTTP as a lowest common denominator.
MuntsOS, with its operating system running entirely from RAM, serves well for the Thin Server, and the two concepts have evolved together over the past few years. The simplest way to use MuntsOS is to download one of the prebuilt Thin Server .zip files and extract it to a freshly formatted FAT32 SD card. You can then modify autoexec.d/00-wlan-init on the SD card to pre-configure it for your wireless network environment, if desired, before inserting it in the target board. After booting MuntsOS, log in from the console or via SSH (user "root", password "default") and run sysconfig to perform more system configuration.
Note: Some platforms require the boot flag to be set on the FAT32 boot partition on the SD card or on-board eMMC. The ROM boot loader in the CPU will ignore any partitions that are not marked as bootable.
MuntsOS Application Notes 3 and 15 contain more detailed instructions about how to install a MuntsOS Thin Server.Prebuilt MuntsOS Thin Servers are at available at:
http://repo.munts.com/muntsos/thinservers
The Orange Pi Zero 2W is a small Linux microcomputer with a form factor very similiar to the Raspberry Pi Zero 2 W, making it ideal for embedded system projects. It has a 1500 MHz Allwinner H618 Cortex-A53 quad-core CPU and comes with 1 to 4 GB of RAM and on-board Bluetooth and WiFi radios. It is available for sale on Amazon for $21.99 (1 GB RAM) to $33.99 (4 GB RAM).
Compared to the Raspberry Pi Zero 2 W, its greater RAM is a big advantage and I have been able to purchase as many as I want without limits when the Raspberry Pi Zero 2 W has been unavailable.
Its big disadvantage is that its manufacturer kernel source tree has not been maintained regularly and is currently at 6.1.31. Mainline Linux does contain support for the Orange Pi Zero 2W and I am currently building a booting kernel from the 6.12 LTS mainline branch. Much work remains to be done both with its kernel configuration and its device tree.
The Raspberry Pi is a family of low cost Linux microcomputers selling for USD $15 to $80, depending on model. There have been five generations of Raspberry Pi microcomputers, each using a successively more sophisticated Broadcom ARM core CPU. The first two generations (32-bit ARMv6 Raspberry Pi 1 and 32-bit ARMv7 Raspberry Pi 2) are now obsolete.
Some Raspberry Pi models have an on-board Bluetooth radio that uses the serial port signals that are also brought out to the expansion header. By default, MuntsOS port disables the on-board Bluetooth radio, in favor of the serial port on the expansion header.
All of the following 64-bit Raspberry Pi models use the same AArch64 cross-toolchain.
The Raspberry Pi 2 Model B Revision 1.2 with the 900 MHz BCM2710 ARMv8 Cortex-A53 quad-core CPU can be treated as a power conserving Raspberry Pi 3 Model B− and is useful for industrial applications where wired Ethernet is preferred.
The Rasbperry Pi 3 Model B has a 1200 MHz BCM2710 ARMv8 Cortex-A53 quad-core CPU and has 1 GB of RAM along with on-board Bluetooth and WiFi radios.
The Raspberry Pi 3 Model A+ has the same form factor as the Raspberry Pi 1 Model A+, with only one USB host port and no wired Ethernet. It has a 1400 MHz BCM2710 ARMv8 Cortex-A53 quad-core CPU and has 512 MB of RAM along with on-board Bluetooth and WiFi radios.
The Raspberry Pi 3 Model B+ has a 1400 MHz BCM2710 ARMv8 Cortex-A53 quad-core CPU and has improved power management and networking components.
The Raspberry Pi Zero 2 W has the same form factor as the Raspberry Pi Zero W, with a 1000 MHz BCM2710 ARMv8 Cortex-A53 quad core CPU and 512 MB of RAM along with on-board Bluetooth and WiFi radios. This small, light, and inexpensive board is probably one of the best Linux microcomputers available for implementing embedded systems.
All Raspberry Pi 3 models use the same ARMv8 kernel, with different device trees.
The Raspberry Pi 4 Model B has a 1500 MHz BCM2711 ARMv8 Cortex-A72 quad-core CPU and is available with 1 to 8 GB of RAM. It diverged significantly from the Raspberry Pi 1 B+ form factor, with the USB and Ethernet ports reversed, two micro-HDMI connectors instead of a single full size HDMI connector, and a USB-C power connector instead of micro-USB. Two of the USB ports are 3.0 and two are 2.0. A major improvement is a Gigabit Ethernet controller connected via PCI Express instead of the USB connected Ethernet used for all earlier models. The Raspberry Pi 4 Model B uses the same wireless chip set as the 3+.
There are also a myriad of Raspberry Pi 4 Compute Modules, with varying combinations of wireless Ethernet, RAM and eMMC.
All Raspberry Pi 4 models use the same ARMv8 kernel, with different device trees.
The Raspberry Pi 5 yields another 2-3x increase in performance over the Raspberry Pi 4, at the expense of greater power consumption. It has a 2400 MHz BCM2712 ARMv8 Cortex-A76 quad-core CPU and is available with 4 or 8 GB of RAM. The Ethernet socket and USB ports have swapped sides, so it has a form factor that is sort of a cross between the Raspberry Pi 1 B+ (same grouping of Ethernet and USB ports) and the Raspberry Pi 4 (same dual micro-HDMI sockets and USB-C power socket).
There are also a myriad of Raspberry Pi 5 Compute Modules, with varying combinations of wireless Ethernet, RAM and eMMC.
All Raspberry Pi 5 models use the same ARMv8 kernel, with different device trees.
The Raspberry Pi 5 introduced a breaking GPIO API change. See Application Note #11 for more information.
The Raspberry Pi 5 also introduced a breaking PWM API change. It has four hardware PWM outputs with different pin mapping. Notably, PWM chip 2 channel 2 is mapped to GPIO18 instead of PWM chip 0 channel 0 on previous Raspberry Pi boards. See RP1 Peripherals page 15 for more information.
MuntsOS also provides Raspberry Pi kernels with dedicated USB Gadget support enabled. These kernels run on 3 A+, CM3, Zero 2 W, 4 B, and CM4. You can supply power to and communicate with a compatible Raspberry Pi solely through the USB port. This kernel supports USB Network, Raw HID, and Serial Port gadgets, selected by bits in the OPTIONS word passed on the kernel command line. The USB Gadget Thin Servers have USB Network Gadget selected by default.
The absolute minimum possible usable Raspberry Pi kit consists of a Raspberry Pi Zero 2 W, a micro-USB cable, and a micro-SD card with one of the MuntsOS Raspberry Pi 3 USB Gadget Thin Servers installed.
I build a custom Ada/C/C++/Fortran/Go/Modula-2 GCC cross-toolchain for each MuntsOS platform family. Each GCC cross-toolchain requires a number of additional software component libraries, which are packaged and distributed separately but installed into the same directory tree as the parent cross-toolchain. I also build Free Pascal cross-compilers. Each of these rely on the libraries contained in the corresponding GCC cross-toolchain package.
Cross-toolchain packages built for Debian Linux (x86-64 and ARM64) development host computers are available at either:
http://repo.munts.com/debian12 (Debian package repository)x86-64 RPM packages containing the exact same binaries and known to work on Fedora 40 and RHEL 9.1 and its derivatives are available at:
http://repo.munts.com/muntsos/toolchain-rpmsAdding muntsos_aarch64 to an Alire Ada program project turns it into one that produces a cross-compiled AArch64/ARMv8 program for MuntsOS. See Application Note #7 for a complete example using the alr command line tool.
Please note that none of the other MuntsOS library crates in Alire (e.g. muntsos_beaglebone) are useable due to breaking changes in alr 2.0. Unfortunately, Alire project policies prohibit removing obsolete crates, so muntsos_beaglebone et al remain in the repository as broken and abandoned orphans.
With the dotnet extension installed, MuntsOS can run architecture independent .Net programs produced by dotnet build, dotnet publish, dotnet pack or the equivalent actions in Microsoft Visual Studio. Many if not most of the library packages published on Nuget can be used. In particular, the NuGet library package libsimpleio provides libsimpleio.dll, .Net Standard 2.0 library assembly that binds to the Linux shared library libsimpleio.so that is an integral part of MuntsOS. See Application Note #8 for a complete example using C# to flash an LED. See also the API specification for libsimpleio.dll.
The combination of Visual Studio + NuGet + libsimpleio provides a very high productivity development environment for creating embedded systems software to run on MuntsOS. With RemObjects Elements, a commercial Visual Studio addon product, you can even compile Object Pascal, Java, Go, and Swift programs, all using libsimpleio.dll, to .Net program assemblies that run on MuntsOS.
The source code for MuntsOS is available at:
https://github.com/pmunts/muntsos
Use the following command to clone it:
git clone https://github.com/pmunts/muntsos.git
Prebuilt binaries for MuntsOS (extensions, kernels, thin servers, and cross-toolchain packages) are available at: