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Real-time clocks: Does anybody really know what time it is?

Jason Sachs May 29, 20118 comments

We recently started writing software to make use of a real-time clock IC, and found to our chagrin that the chip was missing a rather useful function, namely elapsed time in seconds since the standard epoch (January 1, 1970, midnight UTC).Let me back up a second.A real-time clock/calendar (RTC) is a micropower chip that has an oscillator on it that keeps counting time, independent of main system power. Usually this is done with a lithium battery that can power the RTC for years, so that even...


VHDL tutorial - A practical example - part 2 - VHDL coding

Gene Breniman May 27, 2011

In part 1 of this series we focused on the hardware design, including some of the VHDL definitions of the I/O characteristics of the CPLD part.  In part 2, we will describe the VHDL logic of the CPLD for this design.

With any design, the first step to gather the requirements for the job at hand.  From part 1 of this article, I have copied two sections that address some of the requirements for the CPLD design.

The data acquisition engine has the...


Tracing code and checking timings

Richard Dorfner May 25, 20115 comments

Debugging resource limited systemsApplications writers that write code on large systems have it easy. Well, perhaps not easy, but certainly easier. There are some things that they don't have to worry about and there is a huge array of tools available to them when it comes time to debug. The have choices in their toolsets, lots of choices. They also have a large selection of available methods for getting debugging information out to them such as log files, proc entries, pop up dialog boxes or...


VHDL tutorial - A practical example - part 1 - Hardware

Gene Breniman May 18, 20111 comment

In previous posts I described some simple VHDL examples.  This time let's try something a little more complex. This is part one of a multiple part article.  This is intended to be a detailed description of one of several initial designs that I developed for a client.  This design never made it into a product, but a similar design was used and is currently being produced.  As a considerable amount of work was put into this effort, I decided to share this design...


Byte and Switch (Part 1)

Jason Sachs April 26, 201114 comments

Imagine for a minute you have an electromagnet, and a microcontroller, and you want to use the microcontroller to turn the electromagnet on and off. Sounds pretty typical, right?We ask this question on our interviews of entry-level electrical engineers: what do you put between the microcontroller and the electromagnet?We used to think this kind of question was too easy, but there are a surprising number of subtleties here (and maybe a surprising number of job candidates that were missing...


Good old multiplexed keypad in an embedded system

Jayaraman Kiruthi Vasan April 17, 20118 comments

Good old multiplexed keypad in embedded systems

(My www.embeddedrelated.com Blog No.1)

Touch-screens, rotary encoder switches and other navigational aids rule the user interface these days.  Navigation through menus and sub-menus is child’s play as icons and thumbnails rule the screen.

 

Jumping from one screen to another, switching between programs and event notification pop-ups are made possible due to high...


VHDL tutorial - Creating a hierarchical design

Gene Breniman May 22, 20086 comments

In earlier blog entries I introduced some of the basic VHDL concepts. First, developing a function ('VHDL tutorial') and later verifying and refining it ('VHDL tutorial - part 2 - Testbench' and 'VHDL tutorial - combining clocked and sequential logic'). In this entry I will describe how to...


VHDL tutorial - combining clocked and sequential logic

Gene Breniman March 3, 2008

In an earlier article on VHDL programming ("VHDL tutorial" and "VHDL tutorial - part 2 - Testbench", I described a design for providing a programmable clock divider for a ADC sequencer. In this example, I showed how to generate a clock signal (ADCClk), that was to be programmable over a series of fixed rates (20MHz, 10MHz, 4MHz, 2MHz, 1MHz and 400KHz), given a master clock rate of 40MHz. A reader of that article had written to ask if it was possible to extend the design to...


Designing Embedded Systems with FPGA-2

Pragnesh Patel November 13, 200710 comments

In last part, we created hardware design of basic system. The next step is to generate (compile) hardware design. Compiled hardware design is known as bit-stream andstored in *.bit file. To compile hardware, use hardware->generate hardware tab. The complete hardware design generation takes several seconds to several minutes depending on computer speed and design complexity. In back ground, the whole design process involves many different steps including synthesis, placement, routing and...


VHDL tutorial - part 2 - Testbench

Gene Breniman October 30, 20073 comments

In an earlier article I walked through the VHDL coding of a simple design. In this article I will continue the process and create a test bench module to test the earlier design. The Xilinx ISE environment makes it pretty easy to start the testing process. To start the process, select "New Source" from the menu items under "Project". This launches the "New Source Wizard". From within the Wizard select "VHDL Test Bench" and enter the name of the new module (click 'Next' to...


Getting Started With Zephyr: West Manifest Customization

Mohammed Billoo April 4, 2023
Introduction

The Zephyr Project RTOS (https://zephyrproject.org/), or simply “Zephyr” as it is known colloquially, is an increasingly popular real-time operating system due to its native support for over 450 boards and countless peripherals. When starting with any embedded software project, the first task is to start from a known baseline. This can include cloning a repository from source control, which can be the case with embedded Linux, or downloading a zip file representing a...


Kind of Buggy! The state machine fantastic//

Richard Dorfner August 31, 20112 comments

Over the years, I have had the opportunity to experience a lot of different kinds of coding mistakes. There were many that most programmers are familiar with, counting errors, indexing errors (the infamous 'off by one' bug), memory space sharing errors (A threading issue) as well as numerous others.  I ran into one recently that I wound up using an old trick to help find.

My current project is a Pan/Tilt camera that was, upon occasion, not homing properly in one axis. The camera is a...


LCD Control with an MCU

Dr Cagri Tanriover November 17, 20129 comments

 Controlling a liquid crystal display (LCD) to indicate a few ASCII characters should not be a big challenge as a project. That’s exactly what I thought when I decided to include a 2 line by 16 character display in my current project. My initial thought was. “How difficult could it be with all the resources on the internet and my embedded development expertise primarily in telecoms?” Let me tell you it is not as straightforward as I thought it would be and therefore I...


Getting Started With Zephyr: Devicetrees

Mohammed Billoo July 18, 20232 comments

This blog post provides an introduction to the "Devicetree", another unique concept in The Zephyr Project. We learn about the basic syntax of a device tree and how its structure and hierarchy mirror hardware, from the SoC to the final board. We also see how hardware described in a devicetree can be referenced and controlled in the source code of a Zephyr-based application.


Embedded Software Creation II - European Normative & Legislation

Dr. Maykel Alonso December 20, 20116 comments

In this post I will explain the European Normative. I will answer the main questions and I will be open to answer all the doubts any of you could have. Please leave a comment and I will answer if i could.

Why I need to look and accomplish some standards? 

The main reason is if you want to comercialize the product in the European Union, if exists any European Directive that cover the product, the product must be marked with the CE mark. For USA it work in the same way by the...


Tracing code and checking timings

Richard Dorfner May 25, 20115 comments

Debugging resource limited systemsApplications writers that write code on large systems have it easy. Well, perhaps not easy, but certainly easier. There are some things that they don't have to worry about and there is a huge array of tools available to them when it comes time to debug. The have choices in their toolsets, lots of choices. They also have a large selection of available methods for getting debugging information out to them such as log files, proc entries, pop up dialog boxes or...


Layout recomendations and tips for best performance against EMC

Dr. Maykel Alonso January 4, 2013

When making the layout of the circuit diagram, it is interesting to perform a preliminary analysis of several issues in order to minimize problems arising from electromagnetic compatibility.The analysis consists in:

Identify / Analyze components: This section will analyze the integrated components, as well as any recommendations it may have the manufacturer. We must also analyze the encapsulation possibilities which have the component.


Intro to Microcontrollers Part 2: AVR Microcontrollers

July 11, 2013
Introduction

This is part 2 of my playing around with AVR microcontrollers. Last time, I had a basic setup which could program an AVR using the Arduino ISP. I used it to drive a simple 7-segment, multiplexed 4-digit LED display. This is a follow up where I try out some of the other features the ATTiny24A has to offer. I also decided to invest some money in an AVR Dragon programmer/debugger so I'll go over some basic playing and setup with this device. I'll also discuss some of the problems...


Getting Started with (Apache) NuttX RTOS Part 2 - Looking Inside and Creating Your Customized Image

Alan C Assis July 5, 2023

In the previous article (https://www.embeddedrelated.com/showarticle/1524.p...) we saw how to run NuttX RTOS using the SIMulator. Today we will see how NuttX's directory tree is organized and how to use the menuconfig to enable some applications, including some tricks to search and solve dependencies.

NuttX Directories organization:

If you have previously compiled the Linux kernel or the U-Boot bootloader you will see that the NuttX source tree organization is very...


Bellegram, a wireless DIY doorbell that sends you a Telegram message

Sergio R Caprile July 9, 2023

A wireless button that uses the M5 STAMP PICO and Mongoose to send a Telegram message when pressed. The code is written in C