Articles

AVRILOS: A simple OS for AVR microcontrollers

An Embedded System simple Operating System Framework that allows rapid development of applications build for AVR family but can be ported to other architectures easily enough. In this article I will describe the concepts and the structure of this OS and also I will provide an example application in order for the reader to understand the simplicity of building new stuff easily.

AVRILOS SysTick Timer enhancements

Xilinx FPGA with AVRILOS

In a previous article I presented the AVRILOS round-robin operating system. In this article I will describe the process to integrate FPGA configuration data into your code and be able to configure FPGA devices without the need of an external serial or PROM/Flash. This will reduce chip count if you integrate FPGAs with a microcontroller as I often do. Also I will present a simple VHDL SSI/SPI interface in VHDL that you can use as peripheral FPGA which you can control through AVRILOS.  The example application is a 8 channel R/C Servo controller which is demonstrated through a video presentation.

Convert Xilinx FPGA.CPLD to C Source

In a previous article, I presented the AVRILOS round-robin operating system. In this article, I will describe the process and tools to generate FPGA configuration data for integration into your code and be able to configure FPGA devices without the need of an external serial or PROM/Flash. This will reduce chip count if you integrate FPGAs with a microcontroller as I often do. I will also present a makefile for compiling the Xilinx FPGA code. In a following article, I will present how to download and use this code from AVRILOS.

COFILOS SD Card Driver

Last year, I completed a major milestone for COFILOS and the Perseus board. I completed a fully TDD written SD Card Driver. You may check the following video COFILOS SD Card.

It was a big pain to write it, even though I had guide code from the internet and enough relevant information. The outcome is a very readable and organized code.

How to debug embedded systems, article in EDN

Decoding Serial Busses from Digital Oscilloscope

Using a Digital Oscilloscope was a premium tool in the past; although professional equipment is still a high cost if considered for amateur use, the cost of equipment has fallen in the last years allowing more people to get these instruments.

The good thing with such instruments is that they usually provide some connectivity with serial, ethernet or USB connection. Usually apart from any web based control, you have the option to program the instrument through the SCPI interface. You may use any language you want if you want to access the instrument as long as you have installed the relevant VISA libraries/drivers like National Instruments NIVISA, or the Tektronix TekVISA (see below for links).

To RTOS or not to RTOS?

Often in the embedded world, the question of using a Real-Time Operating System (RTOS) or not, is the big question amongst engineers. The answers found on-line are usually biased opinions without metrics or scientific support of the argument. They usually state the advantages or disadvantages over the classic round-robin systems. The truth is that engineers prefer and like evidence instead of heuristics. I will try to answer this, as I did for myself. I believe this small guide will help decide if an RTOS is worth the effort or not.