C++ on microcontrollers 2 - LPCXpresso, LPC-link, Code Sourcery, lpc21isp, linkerscript, LPC1114 startup
previous parts: 1
This blog series is about the use of C++ for modern microcontrollers. My plan is to show the gradual development of a basic I/O library. I will introduce the object-oriented C++ features that are used step by step, to provide a gentle yet practical introduction into C++ for C programmers. Reader input is very much appreciated, you might even steer me in the direction you find most interesting.
I teach my students that...
Using XML to describe embedded devices (and speak to them)
This article discusses one of the typical development cycles in embedded device and communication design and presents a possible, light weight solution using the free DClib/netpp framework.
The challengeAssume we're faced with the design of an embedded device, be it a simple SoC unit or a more complex, uC controlled engine with various attached peripherals. From first prototype to the market, the following development cycle is typically walked through:
C++ on microcontrollers 1 - introduction, and an output pin class
This blog series is about the use of C++ for modern microcontrollers. My plan is to show the gradual development of a basic I/O library. I will introduce the object-oriented C++ features that are used step by step, to provide a gentle yet practical introduction into C++ for C programmers. Reader input is very much appreciated, you might even steer me in the direction you find most interesting.
I am lazy. I am also a programmer. Luckily, being a lazy...
Which MOSFET topology?
A recent electronics.StackExchange question brings up a good topic for discussion. Let's say you have a power supply and a 2-wire load you want to be able to switch on and off from the power supply using a MOSFET. How do you choose which circuit topology to choose? You basically have four options, shown below:
From left to right, these are:
High-side switch, N-channel MOSFET High-side switch, P-channel MOSFET Low-side switch, N-channel...Kind of Buggy! The state machine fantastic//
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...
Deeply embedded design example - Logic replacement
I have always believed that some of the low-cost, low-pin count, low-resource microprocessors would make an excellent choice for the replacement of discrete logic components. In these cases the deeply embedded microprocessor would become less of a general purpose computer and more of a logic replacement, providing a prescribed function with no connection to the outside world. In a world of bigger, faster and more expensive, it is a pleasant change of pace...
VHDL tutorial - A practical example - part 3 - VHDL testbench
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 described the VHDL logic of the CPLD for this design. In part 3, we will show the entire VHDL design and the associated tests used to prove that we have, in fact, designed what we started out to design.
First, let's pull all of the pieces of the prior design together into a...
Thermistor signal conditioning: Dos and Don'ts, Tips and Tricks
In an earlier blog entry, I mentioned this circuit for thermistor signal conditioning:
It is worth a little more explanation on thermistor signal conditioning; it's something that's often done poorly, whereas it's among the easiest applications for signal conditioning.
The basic premise here is that there are two resistors in a voltage divider: Rth is the thermistor, and Rref is a reference resistor. Here Rref is either R3 alone, or R3 || R4, depending on the gain...
Real-time clocks: Does anybody really know what time it is?
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
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...
C++ on microcontrollers 3 – a first shot at an hc595 class with 8 output pins
This blog series is about the use of C++ for modern microcontrollers. My plan is to show the gradual development of a basic I/O library. I will introduce the object-oriented C++ features that are used step by step, to provide a gentle yet practical introduction into C++ for C programmers. Reader input is very much appreciated, you might even steer me in the direction you find most interesting.
In the first part of...
Favorite Tools: C++11 std::array
Many embedded software and firmware projects must be developed to high standards of reliability. To meet these reliability requirements, firmware project teams will consider many design tradeoffs. For example, an engineering team may avoid or outright ban the use of dynamic memory allocation, a feature typically accessed via the C library call "malloc" or the C++ allocator "new". When authoring software under such...
Bellegram, a wireless DIY doorbell that sends you a Telegram message
A wireless button that uses the M5 STAMP PICO and Mongoose to send a Telegram message when pressed. The code is written in C
Making a connection 1
In order for your system to control devices, you must be able to connect it to those devices.
Besides different sizes based on wire size, there are a few different styles of connectors that can be used. There are also weather-resistant terminals that can be used if needed.
Ring
(Parks, 16)
- used for circuits that you don’t want to become easily disconnected
- ground wire attached to a stud
Push-On
- can be used on relay terminals
(Parks, 18)
- could be...
Arduino robotics #3 - wiring, coding and a test run
Arduino Robotics
Arduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around $50.
1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.Kind of Buggy! The state machine fantastic//
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...
Deeply embedded design example - Logic replacement
I have always believed that some of the low-cost, low-pin count, low-resource microprocessors would make an excellent choice for the replacement of discrete logic components. In these cases the deeply embedded microprocessor would become less of a general purpose computer and more of a logic replacement, providing a prescribed function with no connection to the outside world. In a world of bigger, faster and more expensive, it is a pleasant change of pace...
Designing Embedded Systems with FPGA-2
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...
Embedded Programming Video Course Shows How OOP Works Under the Hood
If you'd like to understand how Object-Oriented Programming (OOP) really works under the hood, here is a free video course for you:
OOP part-1: Encapsulation: This first lesson on Object-Oriented Programming (OOP) introduces the concept of Encapsulation, which is the ability to package data and functions together into classes. You'll see how you can emulate Encapsulation in C, what kind of code is generated, and how to debug such code. Next, you will translate the C design into C++ using...
Arduino robotics #4 - HC-SR04 ultrasonic sensor
Arduino RoboticsArduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around $50.
1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.Lost Secrets of the H-Bridge, Part V: Gate Drives for Dummies
Learn the most important issues in power MOSFET and IGBT gate drives: - Transistor behavior during switching - Calculating turn-on and turn-off times - Passive components used between gate drive IC and transistor - Reverse recovery - Capacitively-coupled spurious turn-on - Factors that influence a good choice of turn-on and turn-off times - Gate drive supply voltage management - Bootstrap gate drives - Design issues impacting reliability
Motion Sensor with Raspberry Pi and MPU6050 - Part 1
This blog will help you build your own, low cost 3-axis motion sensor using Raspberry Pi and Invensense MPU6050.
NXP LPC17xx/40xx: Decoding the Part ID
This is the first blog of a number dealing with the NXP LPC17xx/40xx processor families and how to program them despite the lack of documentation. The next blog will deal with implementing the LPC17xx/40xx UART with interrupts properly, and a subsequent blog will show how to use the UART in RS485 Normal Multidrop Mode (NMM) with Auto Address Detection (AAD).
My company has decided on using the NXP LPC17xx/40xx processor line for all our embedded projects. Since...
Getting Started With Zephyr: Writing Data to EEPROM
In this blog post, I show how to implement a Zephyr application to interact with EEPROM. I show how the Zephyr device driver model allows application writers to be free of the underlying implementation details. Unfortunately, the application didn't work as expected, and I'm still troubleshooting the cause.
Making a connection 1
In order for your system to control devices, you must be able to connect it to those devices.
Besides different sizes based on wire size, there are a few different styles of connectors that can be used. There are also weather-resistant terminals that can be used if needed.
Ring
(Parks, 16)
- used for circuits that you don’t want to become easily disconnected
- ground wire attached to a stud
Push-On
- can be used on relay terminals
(Parks, 18)
- could be...
Five Embedded Linux Topics for Newbies !
Are you an embedded systems enthusiast looking to broaden your horizons with embedded Linux? explore those 5 topics.
Kind of Buggy! The state machine fantastic//
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...
Getting Started With Zephyr: Saving Data To Files
In this blog post, I show how to implement a Zephyr application to mount a microSD card, create a new file on the microSD card, and write data to it. The lessons learned from such an application can be helpful for devices out in the field that need to write data to off-board memory periodically, especially in cases where Internet access may be sporadic.
LCD Control with an MCU
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 (Apache) NuttX RTOS Part 2 - Looking Inside and Creating Your Customized Image
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...
