/Tag: microcontrollers

Global and Local Variables in Embedded C Programs

There are two main concepts that have to be explained in order for us to fully understand the differences between global and local variables in C programs: Scope  -  determines the region of the program where a variable can be accessed Storage Duration - determines when a variable is created and destroyed (lifetime of the variable) [...]

By |2019-05-18T23:36:48+03:00May 11th, 2017|Categories: Embedded Systems|Tags: |0 Comments

Memory Layout of Embedded C Programs

The memory layout of C programs consists of several segments. The segments accessible to a user program are shown in the figure below:   Fig. 1 C program memory layout Code Segment (.text)   This segment stores the executable program code (the machine instructions). Variables defined with the const type qualifier can also be placed [...]

By |2019-05-18T23:19:36+03:00May 2nd, 2017|Categories: Embedded Systems|Tags: |4 Comments

The Boot Process of a Microcontroller

Overview Even though the boot process can be a complex sequence involving multiple steps it always starts with the same first step. When the power-on reset sequence is finished and the CPU comes out of reset, the program counter is pointing to the address of the reset vector (boot vector). This address contains the first instruction that [...]

By |2019-05-18T23:41:04+03:00April 15th, 2017|Categories: Embedded Systems|Tags: |1 Comment

The Concept of Heap and Its Usage in Embedded Systems

Overview A typical memory representation of a C language program consists of following segments:  Code (Text) segment - contains the program code (machine instructions)  Data segment - contains the static data (global/static variables)  Stack segment (see our article on the topic The Concept of Stack and Its Usage in Microprocessors)  Heap segment Fig.1 Memory Segments [...]

By |2019-05-18T23:23:52+03:00April 2nd, 2017|Categories: Embedded Systems|Tags: |0 Comments

Fixed Point Numbers in Digital Systems

Overview Fixed point numbers are used for representing fractional numbers in digital systems. The term "Fixed-Point" refers to fact that the position of the binary point is always at the same place. The binary point separates the integer and the fractional part of a number (the same as the decimal point in the decimal system). An N-bit binary [...]

By |2019-05-18T23:28:43+03:00February 8th, 2017|Categories: Digital Logic|Tags: |0 Comments

Floating Point Numbers in Digital Systems

Overview Floating point is a way of  representing rational numbers in digital systems. The floating point numbers are represented  in a manner similar to scientific notation, where a number is represented as normalized significand and a multiplier: c x be  Scientific notation c - normalized significand  (the absolute value of c is between 1 and 10 e.g [...]

By |2019-05-18T23:29:57+03:00January 14th, 2017|Categories: Digital Logic|Tags: |0 Comments

Phase Locked Loop (PLL) and Delay Locked Loop (DLL) Basics

Phase-Locked Loop (PLL) A PLL is a negative feedback system where an oscillator-generated signal is phase and frequency locked to a reference signal. Typical applications of PLL are: Frequency Synthesis (e.g. generating a 1 GHz clock from a 50 MHz reference) Clock Deskewing (e.g. phase-aligning an internal clock to an output clock to external device) Extracting [...]

By |2019-04-07T13:33:32+03:00July 28th, 2016|Categories: Explained Simply|Tags: , , |0 Comments

Application of MODBUS Protocol in Microcontrollers

MODBUS© Protocol is a messaging structure, widely used for master-slave communication between devices. Only one master (at the same time) is connected to the bus, and one or several (247 maximum number) slaves nodes are also connected to the same serial bus. When a MODBUS master wants information from a device, the master sends a message that contains [...]

By |2019-05-18T23:33:17+03:00July 25th, 2016|Categories: Embedded Systems|Tags: |1 Comment
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