RTOS: Mutex and Semaphore Basics

Designing an embedded system that employs a real-time operating system (RTOS) with multitasking behavior means that there will be resources that must be shared between the tasks. These shared resources (e.g peripheral modules, data structures, communication interfaces, etc.) by their nature do not support multiple concurrent accesses. Accessing them without any rules in place may

2020-03-16T06:18:21+02:00By |Categories: Embedded Systems|Tags: , , |0 Comments

Exception Context Switching on ARM Cortex-M

This article is a natural extension on the topics we covered in Function Calls on ARM Cortex-M Microprocessors. Due to the hardware specifics of the Cortex-M architecture, there is actually a lot of common in how function calls and exceptions are handled. The good thing for us as developers is that all exception handlers can

2020-02-24T07:20:40+02:00By |Categories: Embedded Systems|Tags: , |0 Comments

RTOS Task Context Switching

In our article covering the scheduling algorithms of real-time operating systems (RTOS), we stated that they can run tasks in such a way that leaves the impression of a multitasking behavior. This is achieved by giving the RTOS the capability to interrupt a currently executing task and to start executing another one. At some point

2020-01-06T05:50:26+02:00By |Categories: Embedded Systems|Tags: , , |2 Comments

RTOS Scheduling Algorithms

We already introduced the basic concepts of real-time operating systems (RTOS) and now we will take a deeper look into one of the most important things when designing an embedded system using an RTOS - the scheduling of the tasks and the algorithms that are used. Scheduling Process Scheduling is the process of deciding which

2019-12-10T20:49:41+02:00By |Categories: Embedded Systems|Tags: , , |0 Comments

Embedded Real-Time Operating System (RTOS) Basics

Embedded systems are microcontroller-based systems that are designed to perform specific functions such as reading sensor data, responding to external events, communicating with other systems, controlling processes, etc. The tricky part is to make the distinction of what exactly qualifies such a system as real-time. Aren't all embedded systems operating in real-time? In order for

2019-10-26T22:27:34+03:00By |Categories: Embedded Systems|Tags: , , |0 Comments

Digital Buffers And Their Usage

In this article, we will explain the functionality of two very important electronic circuit elements: digital buffer and tri-state digital buffer. Buffer At first glance, the functionality of a digital buffer may seem very simple: the value at its input is propagated to its output. Fig. 1 Buffer symbol and truth table If the buffer

2019-05-19T16:48:41+03:00By |Categories: Digital Logic|Tags: , |0 Comments

Open Drain Output vs. Push-Pull Output

Microcontrollers use pins for interfacing with the outside world. In general, the pins are the physical points on the package of an integrated circuit (IC) where a connection can be made to the printed circuit board.  Behind each pin (inside the IC) there is a special circuitry used for driving it. This circuitry (usually called a

2019-05-18T22:57:15+03:00By |Categories: Embedded Systems|Tags: |8 Comments

Memory Addressing Modes

Addressing Mode refers to the way the actual location of an instruction's operand is specified. It is used in the decode phase of the instruction cycle to extract the operand of the instruction so the proceeding execute phase can start. The main purpose of having different addressing modes is to provide flexibility when referencing the memory location of

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