Development of the MOS Technology 6502: A Historical Perspective
A tiny team at MOS Technology pulled off one of the most influential microprocessor wins of the 1970s, creating the 6502 by marrying clever circuit choices with pragmatic manufacturing techniques. This excerpt by Jason Sachs focuses on the NMOS depletion-load process, mask and layout workflows, and yield-improving tricks like Micralign projection lithography and spot-knocking, showing how engineering and process decisions made a low-cost CPU ubiquitous.
Supply Chain Games: What Have We Learned From the Great Semiconductor Shortage of 2021? (Part 2)
Jason Sachs zooms through semiconductor history, fab economics, and the microcomputer era to explain why the 2021 chip shortage unfolded the way it did. He blends technical explainers on photolithography, yields, and node migration with business lessons about risky multi-year fab investments and cyclic demand. Engineers get historical case studies and practical signals to watch when designing products for greater supply resilience.
Patterns of Thinking: Metaphors in Programming
Why do some programming ideas click while others confuse engineers? This post shows that the metaphors you choose — from biological classification for inheritance to a “quantum” analogy for hierarchical state machines — shape how developers learn, design, and communicate. It also explains the surprising power of anthropomorphic (“naïve psychology”) language in team discussions and gives practical cautions about when metaphors help or mislead.
New Promo Video for the 2022 Embedded Online Conference
Less than a week remains before the 2022 Embedded Online Conference, and Stephane Boucher shares a new promo video that previews an all-star lineup of embedded engineers, shown in order of appearance: Helen Leigh, Peter McLaughlin, Jack Ganssle, Colin O'Flynn, Miro Samek, Jean Labrosse and others. If you haven't registered yet, watch the video and save $100 on registration with promo code EMBEDDEDRELATED.
2022 Embedded Online Conference - Final Push!
The Embedded Online Conference is just weeks away, and Stephane Boucher is making one last push to get the word out. Engineers who share the conference promo image on LinkedIn or Twitter can enter a raffle to win one of two Saleae Logic Pro 8 analyzers, with a simple hashtag-based entry process.
Reading and Understanding Profitability Metrics from Financial Statements
Reading a company’s financial statements does not have to feel like accounting homework. Jason Sachs shows how engineers can pull out the most useful profitability signals, especially gross margin and operating margin, from SEC filings and earnings releases. Using semiconductor companies as examples, he explains what those ratios mean, how they’re computed, and why they can hint at business strength or weakness.
A Second Look at Slew Rate Limiters
Picking the right slew rate can cut overshoot dramatically while keeping delay reasonable, Jason shows. He numerically analyzes a feedforward slew-rate-limited step into a normalized second-order system and proposes a simple empirical rule R = Δx/(2π α τ) with α ≈ 1. The post includes Python/Scipy code and a 3→5 V example that demonstrates about a 3× overshoot reduction and a ≈5τ peak delay.
Supply Chain Games: What Have We Learned From the Great Semiconductor Shortage of 2021? (Part 1)
Jason Sachs argues the 2021 semiconductor shortage was not a single surprise but a set of structural imbalances exposed by COVID-19. He connects long lead times, constrained 200mm fabs and mature-node economics to why automotive features like heated seats became scarce, and shows how bullwhip dynamics and inventory practices amplified the problem. This first part uses concrete anecdotes and simple games to make the supply-chain lessons tangible.
Review: Modern Software Engineering
Long-lived branches, manual releases, and slow feedback waste engineering time. This review of three Dave Farley books distills a practical playbook: continuous delivery pipelines, trunk-based development, and disciplined TDD to keep trunk always releasable. It shows how fast, automated feedback at every stage shrinks cycle time, reduces merge pain, and makes teams far more productive.
VolksEEG: Rust Development On Adafruit nRF52840 Feather Express
Setting up Rust embedded development on an Adafruit Feather nRF52840 Express inside a VS Code devcontainer can save time, but the toolchain has a few gotchas. This post walks through using the VolksEEG prototype echo-server to verify the USB serial path, configuring probe-rs with J-Link and OpenOCD for on-chip debugging, and diagnosing a container build error fixed by adding libudev-dev. Expect step-by-step commands and troubleshooting tips.
Spread the Word and Run a Chance to Win a Bundle of Goodies from Embedded World
EmbeddedRelated is turning Embedded World into a live-streaming experiment, and the more engineers help spread the word, the better the coverage could get. Stephane Boucher is asking readers to follow updates on Twitter and LinkedIn, where every like, share, or repost adds another chance to win a box of vendor goodies. The prize mix includes t-shirts, dev kits, gadgets, and plenty of pens.
Important Programming Concepts (Even on Embedded Systems) Part II: Immutability
Immutable data can make embedded code easier to reason about, reduce concurrency bugs, and eliminate defensive copies. Jason Sachs walks through practical techniques that work in resource-constrained systems, from using const and pseudo-immutability to separating old and new state, to the limits of fully persistent data structures when you lack dynamic memory. The article also compares register-level state flow and advocates message passing as a concurrency alternative.
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.
PC and SP for a small CPU
Victor Yurkovsky walks through a compact stack-based CPU idea that tosses the conventional PC register in favor of a return stack living in Xilinx distributed RAM. The clever twist uses the stack memory addressed by SP as the program counter, making calls trivial and keeping the design tiny. The article shows the Verilog stack module and explains the practical tradeoffs of isolating the return stack.
OOKLONE: a cheap RF 433.92MHz OOK frame cloner
Fabien Le Mentec built a pocket device that listens to and clones 433.92MHz OOK frames, automating the tedious reverse engineering of cheap wireless outlets. The prototype uses a Moteino with an RFM69 to sample demodulated OOK data, stores pulse durations in SRAM, and replays frames; the code and hardware notes are available on GitHub along with limitations and next steps.
Voltage Drops Are Falling on My Head: Operating Points, Linearization, Temperature Coefficients, and Thermal Runaway
A lot of the neat, tidy diode and transistor rules you learned in school are really just approximations. Jason Sachs shows how operating points, linearization, and temperature coefficients give you a better mental model for real circuits, then uses that framework to explain why thermal runaway happens. Along the way, he connects the theory to practical device behavior, op-amp output stages, and the design tricks that keep parts from letting out the magic smoke.
Windows XP and Win32 - the Platform of the Future!
Victor Yurkovsky makes the contrarian case that an offline Windows XP VM running Win32 is the most practical platform for modern FPGA development. He explains how Xilinx ISE and related tools often behave far better under XP than on modern Linux distributions, and how VirtualBox fixes USB and GUI headaches. If you maintain FPGA toolchains or write compact C/C++ utilities, this retro setup can save time and frustration.
Hidden Gems from the Embedded Online Conference Archives - Part 2
A look back at a deep dive into the Mars Perseverance flight software from one of the technical leads at JPL.
Modern Embedded Systems Programming: Beyond the RTOS
Blocking-based RTOS tasks make embedded systems brittle and hard to extend, this post argues, and presents a practical alternative: active objects organized as message pumps. It explains why one-blocking-call tasks and nonblocking event handlers improve responsiveness and reduce task proliferation, and recommends using frameworks plus hierarchical state machines and UML to enforce good architecture and make designs scalable.
Embedded Toolbox: Programmer's Calculator
A tiny but powerful cross-platform tool, QCalc evaluates full C-syntax expressions so you can paste results straight into firmware. It handles bitwise ops, mixed hex/decimal/binary constants, and scientific math, and it automatically shows integer results in formatted hex and binary. The post explains key features, variable handling, error messages, and how to run qcalc.tcl with the wish Tk interpreter.
Oscilloscope review: Hameg HMO2024
Jason Sachs tests the Hameg HMO2024, a 200MHz 4-channel mixed-signal oscilloscope that promises Agilent-like features at a lower price. He finds strong analog noise performance, useful hi-res and zoom modes, and inexpensive serial-decode options, but warns of clumsy digital-input handling, awkward data-transfer software, and missing per-channel thresholds and Ethernet waveform export. The review helps budget-conscious embedded engineers weigh the trade-offs.
How to make a heap profiler
A heap profiler is surprisingly simple to build, and Yossi Kreinin walks through a compact working example called heapprof. The post shows how to intercept malloc/free, stash per-allocation metadata and call stacks into heap chunks, dump memory on crash or via JTAG, and map return addresses to source lines with addr2line or gdb. It also covers practical bootstrapping tricks for platforms without standard libc support.
Are We Shooting Ourselves in the Foot with Stack Overflow?
Most traditional, beaten-path memory layouts allocate the stack space above the data sections in RAM, even though the stack grows “down” (towards the lower memory addresses) in most embedded processors. This arrangement puts your program data in the path of destruction of a stack overflow. In other words, you violate the first Gun Safety Rule (ALWAYS keep the gun pointed in a safe direction!) and you end up shooting yourself in the foot. This article shows how to locate the stack at the BEGINNING of RAM and thus point it in the "safe" direction.
Designing Communication Protocols, Practical Aspects
When your MCU must talk to a PC or smartphone, a clear protocol saves time and headaches. This post gives practical guidance for fast bring-up: how to structure a compact header, keep payloads byte-aligned and debug-friendly, and reserve bits for future use. It also covers CRCs for integrity, timeout and retry strategies for resynchronisation, and the simple start code trick that makes debugging easier.
Isolated Sigma-Delta Modulators, Rah Rah Rah!
Analog isolation can blow up DAQ budgets, but isolated sigma-delta modulators let you send a single 1-bit stream and a clock across the barrier, keeping costs down. Jason walks through Avago, TI, and Analog Devices parts, explains sigma-delta noise shaping in plain terms, and calls out the real engineering work: converting a 10–20 MHz bitstream into usable samples with sinc/CIC decimators or FPGA filtering.
Arduino robotics #2 - chassis, locomotion and power
Lonnie Honeycutt walks through building Clusterbot's round differential-drive chassis, showing how a circular base and Tamiya gearbox simplify turning and torque tradeoffs. The post covers motor selection, wheel fit, balance issues, and a practical two-battery power arrangement with VMOT for the motors and a separate 9V for the Arduino. Expect hands-on tips and lessons learned from a first-time robot build.
Coding Step 2 - Source Control
Version control felt unnecessary to Stephen Friederichs when he was starting out, but this article shows why Git quickly becomes essential even for solo firmware work. He walks through installing Git on Windows, creating a repository for a simple Hello World project, making the first commit, and using reset to recover from a broken build. The post also captures a few early habits that save a lot of pain later, like committing often and keeping important files under source control.
Fit Sixteen (or more) Asynchronous Serial Receivers into the Area of a Standard UART Receiver
Michael Morris shows how to pack many asynchronous serial receivers into the area of a single UART by treating FPGA LUTs as writable storage and sharing logic. Using a 4-bit channel counter, microprogrammed state machine, and time-multiplexed baud/sample resources, he fits 16 receive channels (12 used for Caller ID) into a Spartan II XC2S30 and explains input synchronization, filtering, and the multi-channel FIFO approach.
Reverse engineering wireless wall outlets
Fabien Le Mentec reverse engineers a cheap set of wireless wall outlets to add them to his BANO home automation while avoiding uncertified mains hardware. He uses PCB inspection to identify a Holtek MCU and RF83C, captures 433.92 MHz OOK signals with an RTL-SDR and ookdump, then replays commands using an RFM22 in direct mode controlled by an ATmega328P. The post explains frame structure and links to a working GitHub implementation.
Bit-Banged Async Serial Output And Disciplined Engineering
This post covers implementing asynchronous serial output directly on a GPIO with bit-banging. This can be a valuable debug tool for getting information out of a system. It also covers disciplined engineering, using the bit-banging module as an example and template you can apply to other projects.
