Use

Kernel

BeRTOS currently supports a number of CPU families:

Have a look at the tutorial section for real world examples for some widespread development boards.

Kernel

BeRTOS features both a preemptive and a cooperative kernel with synchronization primitives.

Embedded systems are mostly I/O bound systems. In these systems the microprocessor/microcontroller spends the most part of its computing power doing... absolutely nothing!

Since the system simply waits for external events to happen we decided to implement a strong and robust kernel with very low memory footprint and high modularity. This allows the kernel to be used on a variety of different CPUs, even the smaller ones.

Currently the kernel code is very stable.

Kernel features

• Preemptive and cooperative round-robin scheduling.
• Heap, for dynamic allocation of processes' memory.
• Stack process monitor, useful to prevent stack overflows.
• Inter-process messaging system. (with very low overhead)
• Binary semaphores with priority inheritance algoritm.
• Signals.

The kernel has a port layer (a single assembly function) that needs to be reimplemented each time a new CPU is added.

Core Drivers

BeRTOS is not only a kernel, it aims to supply full operating system services. To achieve this we need at least some core drivers for every CPU port.

These drivers are: system timer, debug system and serial comm driver.

Adding CPU support for an already present CPU family is quite simple since hardware manufacturers share peripherals design between the same CPU cores.

Core drivers are completely supported on all platforms.

MCU Internal Peripherals Drivers

Since BeRTOS aims to supply full operating system services, for every CPU port we try to implement as much drivers as possible. This section covers the current development status for MCU Internal peripheral drivers.

Driver / MCU family	ADC	UART	FLASH	I2C	PWM	SPI	EMAC
Atmel AVR
Atmel AT91SAM7 ARM
Atmel SAM3N ARM
Atmel SAM3X ARM
STmicro STM32F103xx ARM
Philips LPC23XX ARM
Stellaris LM3S ARM

Generic Indipendent Drivers

BeRTOS supplies a full set of CPU independent generic hardware drivers. To achieve this all drivers are structured to have a hardware abstraction layer (HAL) that isolates CPU specific code and makes porting to new CPU easy.

Current driver list:

File system

BeRTOS supports two file systems. The first one is the mainstream FAT filesystem, using the FatFs library; the second is BattFs, a file system specifically planned for embedded platforms.

File system development takes place in the fs directory.

File System: FAT

The FAT file system is the de-facto standard for removable devices such as SD cards or Memory cards. BeRTOS supports read and write operations on all existing FAT file systems, ranging from FAT12 to FAT32, with support to long file names. This file system is light and fast and allows to easily exchange data through external memory devices.

FAT module is highly configurable, for example it can be compiled in read-only mode for some space saving.

File System: BattFS

BattFS (Batt File System), has been developed to solve problems specific to embedded systems; BattFS is a file system that can be used on any physical media and it's optimized to reduce RAM and ROM usage to meet the strict design guidelines we have used with all the others BeRTOS components.

The goal is to have a filesystem suitable for little flash and eeprom memories (like dataflash), reliable, robust and capable of wear-levelling the memory pages to increase its life.

The code is in beta stage. Currently you can create files, append data to them but file deletion is still not supported. Wear-levelling is achieved by rotating a page every time it is written. Plans are to add even transactions (a whole write can be performed atomically).

BeRTOS Graphics and display management is very advanced. The system includes a complete graphic subsystem that can manage displays with support for fonts, bitmaps, clipping, text formatting and interactive menus, suitable for generating compact yet powerful GUI.

 

This system is composed of several modules ranging from simple graphic primitives to complex menu management functions.

It's also available a console with command parser and command line history support similar to readline.

Algorithms

In embedded programming sometimes you have to cope with protocols, security systems and things like that. BeRTOS comes in help with a set of optimized portable algorithms:

To get up to date informations look at the algorithms source code.

Network protocols

Since BeRTOS can also be used in very tiny systems, some simple communication protocols has been developed.

This is the current status:

For more information take a look at network directory.

Data Structures

BeRTOS supplies common data structures, implemented and optimized for low memory footprint and speed.

Middleware

This section covers all BeRTOS modules that provide general purpose utility functions:

As usual, check source code for detailed reference.