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...
Use DPLL to Lock Digital Oscillator to 1PPS Signal
Introduction There are occasions where it is desirable to lock a digital oscillator to an external time reference such as the 1PPS (One Pulse Per Second) signal output from a GPS receiver. One approach would be to synchronize a fixed frequency...
The habitat of hardware bugs
The Moscow apartment which little me called home was also home to many other creatures, from smallish cockroaches to biggish rats. But of course we rarely met them face to face. Evolution has weeded out those animals imprudent...
Digital PLL's -- Part 2
In Part 1, we found the time response of a 2nd order PLL with a proportional + integral (lead-lag) loop filter. Now let’s look at this PLL in the Z-domain [1, 2]. We will find that the response is characterized by a loop natural...
From Baremetal to RTOS: A review of scheduling techniques
●5 commentsTransitioning from bare-metal embedded software development to a real-time operating system (RTOS) can be a difficult endeavor. Many developers struggle with the question of whether they should use an RTOS or simply use a bare-metal scheduler....
Choosing a Microcontroller for Your Vehicle
There are many things to take into consideration when choosing a microcontroller or microprocessor for your autonomous vehicle.VoltageSome processors run on 5V and others use 3.3V. Be sure to check the documentation before you buy. ...
Digital PLL's -- Part 1
1. Introduction Figure 1.1 is a block diagram of a digital PLL (DPLL). The purpose of the DPLL is to lock the phase of a numerically controlled oscillator (NCO) to a reference signal. The loop includes a phase detector to compute ...
Best Firmware Architecture Attributes
●1 commentArchitecture of a firmware (FW) in a way defines the life-cycle of your product. Often companies start with a simple-version of a product as a response to the time-to-market caveat of the business, make some cash out...
A few uses for an autonomous vehicle
From the time technology that we have come to know was invented, it has been used to gain an advantage militarily or to make life easier. Military usage seems to be a driving factor, but it is not the only factor. Guerilla tactics played...
Stability or insanity
I've just spent over two weeks getting ready to do my next video. It was a combination of one of those vast underestimations one occasionally makes, combined with falling into a bit of an obsession.I am, at this point, not only wondering if...
How to Estimate Encoder Velocity Without Making Stupid Mistakes: Part II (Tracking Loops and PLLs)
●1 commentYeeehah! Finally we're ready to tackle some more clever ways to figure out the velocity of a position encoder. In part I, we looked at the basics of velocity estimation. Then in my last article, I talked a little about what's necessary to...
Chebyshev Approximation and How It Can Help You Save Money, Win Friends, and Influence People
●1 commentWell... maybe that's a stretch. I don't think I can recommend anything to help you win friends. Not my forte. But I am going to try to convince you why you should know about Chebyshev approximation, which is a technique for figuring out how...
Cortex-M Exception Handling (Part 2)
●1 commentThe first part of this article described the conditions for an exception request to be accepted by a Cortex-M processor, mainly concerning the relationship of its priority with respect to the current execution priority. This...
VHDL tutorial - part 2 - Testbench
●4 comments[quicklinks]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...
Lost Secrets of the H-Bridge, Part IV: DC Link Decoupling and Why Electrolytic Capacitors Are Not Enough
●3 commentsThose of you who read my earlier articles about H-bridges, and followed them closely, have noticed there's some unfinished business. Well, here it is. Just so you know, I've been nervous about writing the fourth (and hopefully final) part of this...
Introduction to Microcontrollers - Further Beginnings
●3 commentsEmbedded Programming Basics This tutorial entry will discuss some further embedded programming basics that you will need to understand before proceeding on to the LED blinky and other example programs. We will do this by looking at the...
How FPGAs work, and why you'll buy one
●2 commentsToday, pretty much everyone has a CPU, a DSP and a GPU, buried somewhere in their PC, phone, car, etc. Most don't know or care that they bought any of these, but they did. Will everyone, at some future point, also buy an FPGA? The market size...
Important Programming Concepts (Even on Embedded Systems) Part V: State Machines
●1 commentOther articles in this series: Part I: Idempotence Part II: Immutability Part III: Volatility Part IV: Singletons Part VI: Abstraction Oh, hell, this article just had to be about state machines, didn’t it? State machines! Those...
How to Build a Fixed-Point PI Controller That Just Works: Part I
●4 commentsThis two-part article explains five tips to make a fixed-point PI controller work well. I am not going to talk about loop tuning -- there are hundreds of articles and books about that; any control-systems course will go over loop tuning enough to...
VHDL tutorial - A practical example - part 2 - VHDL coding
●1 comment[quicklinks]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...
