Podd: The Amp Hour Electronics Podcast

#683 – Troubleshooting is the skill

20 november 2024 | min

#682 – Your Mind Is The Tool

6 november 2024 | min

#681 – Compact High Speed Design with Lukas Henkel

31 oktober 2024 | min

#680 – Catching Rockets with Musk Sticks

21 oktober 2024 | min

#679 – Satellite Design Engineering with Dan Esparon

11 oktober 2024 | min

#678 – All About Antennas with Katerina Galitskaya

1 oktober 2024 | min

#677 – Watt Is The Deal

23 september 2024 | min

#676 – Moving House (And Lab)

3 september 2024 | min

#675 – Changing Course with Shawn Hymel

9 augusti 2024 | min

#674 – Turtles as a Service

25 juli 2024 | min

#673 – Lifelong Learning with Bitluni

15 juli 2024 | min

#672 – Silicon Revolution with Matt Venn

30 juni 2024 | min

#671 – NDA Sideshow

20 juni 2024 | min

#670 – Engineering Careers with Circuit Break & James Lewis

14 juni 2024 | min

#669 – Freelance PCB Design with Petr Dvorak

7 juni 2024 | min

#668 – 50.0000 Ohms

31 maj 2024 | min

#667 – Long Distance with CNLohr-a

23 maj 2024 | 91 min

#666 – Good Energy Citizen

8 maj 2024 | 67 min

#665 – Really long needle nose pliers

25 april 2024 | 70 min

#664 – Simulating doors falling off

4 april 2024 | 64 min

#663 – Motors on PCBs with Carl Bugeja

26 mars 2024 | 57 min

#662 – The non-Stinky Car

20 mars 2024 | 66 min

#661 – Blogging Electronics with Pallav Aggarwal

11 mars 2024 | 64 min

#660 – My Toothbrush Is Broadcasting

5 mars 2024 | 66 min

#659 – Altium…Acquired!

20 februari 2024 | 73 min

#658 – Uncle Al’s Eating Garbage Again

13 februari 2024 | 68 min

#657 – Automating the Home with Keith Burzinski

5 februari 2024 | 83 min

#656 – Pneumatic Tubes, Straight To The Home

22 januari 2024 | 74 min

#655 – The Twelfth Day of Keyzermas

9 januari 2024 | 80 min

#654 – Pseudo Code…Pseudo Good

19 december 2023 | 66 min

#653 – Benjamin Cabé Nose Zephyr

11 december 2023 | 67 min

Welcome Benjamin Cabé of The Zephyr Project!

Benjamin is the developer advocate at The Zephyr Project, which is both a Real Time Operating System and an ecosystem (or almost like a “distro”, rather than an OS)
Benjamin does videos on the Zephyr YouTube and maintains an awesome blog / newsletter
The ecosystem is deep: Chris recently learned there is a state machine framework
Multiple people involved in dev like an OS
The Platinmum Members includes chip companies like NXP, Nordic, ADI
There are 600+ boards supported in the ecosystem (and more if you do custom)
Devicetree is a tough concept, but a powerful one that was borrowed from Linux
Who is the audience for Zephyr?
Chromebook embedded controller
What’s the smallest processor that Zephyr can run on? M0s can run it no problem
Chris thinks one of the benefits is the ability to bolt new stuff on to a project
Simulation through Wokwi (Past Guest Uri) or Renode (Past Guest Michael)
Using different levels of abstraction
zephyr i2c init
Benefits of abstraction
- Swapping out chips (bubblegum tapshoes)
- Tying stuff together (bolting stuff on)
- Infrastructure with CI/CD
Zephyr doesn’t have an official IDE but VScode “just works”
Helper tools from Nordic
Open Source
Hobby projects
Dev survey
Custom Keyboards (ZMK)
RP2040 support
Arduino recenlty joined the project
Layers of abstraction
- Architecture (ie. arm, nios2, x86)
- SOC (available peripherals surrounding the core)
- Board (PCB definition which might have:)
  - SOC
  - Memory
  - Peripherals / Sensors
Check the tree and PRs for sensors that might be in-flight
Compared to Arduino IDE
Choosing ecosystems
Weekly newsletter
Things you didn’t know you needed: NMEA subsystem
In Jay Carlson’s 2nd appearance on the show, he said “I’m reading more code than I’m writing”
Benjamin’s profile photo is of his artificial nose he created a few years ago
Making a machine model for bread (pandemic)
It uses TFLite
What is the project doing? (in parallel)
- Acquire data
- Machine learning inference
- Display update
- Network interface
Benjamin reimplemented the Nose in Zephyr using ZBus (Chris recorded a video with the author of this subsystem)
Like an MQTT broker on device
Some of the concerns I (Chris) had when I was starting was not understanding RTOS concepts (threads, queues, etc). Brian Amos was on the show talking about his book, which is a great way to get started with these ideas.
Threading / work queues
The importance of a project when starting out
Starter hardware
- Hero devkits (Chris likes the nRF9160-DK as a starter board or the nRF5340-DK)
- M5stack boards
- iMX8
Jumping down to Zephyr from Linux
MPU + MCU
Tight integration
Zephyr can run POSIX code
What about the the RT in RTOS? Does this operate realtime often? (timing critical)
BOM cost and software cost
Security and dependencies
Join the Zephyr discord to talk to other people using Zephyr
TechTalks / YouTube
Interested in going to a conference in Seattle in 2024 for Zephyr? The ZDS / EOSS CFP is open now!

#652 – For a couple weeks there…

28 november 2023 | 68 min

#651 – Learning Computing with Jeff Geerling

21 november 2023 | 64 min

#650 – Accessible ASICs with Andreas Olofsson

13 november 2023 | 64 min

#649 – History of the Cathode Ray Tube with Kathy Joseph

5 november 2023 | 78 min

#648 – The RP1 and beyond with the Raspberry Pi Hardware team

23 oktober 2023 | 69 min

Welcome back James Adams and Liam Fraser

The RP1 is the new custom silicon on the Raspberry Pi 5 that is the helper chip to the Broadcom part onboard
The HW team was last on the show in 2021 talking about the RP2040
They have been working on the RP1 since 2015
It’s a small team, especially compared to other companies doing custom silicon.
RP2040 update
Scripting to reconfigure the silicon clocks/blocks
Are they making other chips?
Divvy-ing up duties for silicon
Broadcom is making the processor and took input for this latest
Dialog/Renesas do the power chip on the RPi5
PIO
Chris gave an example of a board (the Ostentus) where the PIO is just listening for i2c messages and passing them up the stack.
Design goal was to do cycle by cycle processing
Someone on twitter having PIO talking to fiber transceivers
Sourcing and RP2040 availability
They get 20000 chips per wafer
Buying wafers a few at a time through IMEC, sometimes through TSMC directly
There are often small amounts of availability of “wafer starts”
TSMC40
IP block updates: USB 3 / Ethernet
Can do diffs on the verilog
Receiving high paid IP
Liam is the sysadmin / servers are on site
Buying from Synopsis
Stitching together IP
They list what version of the IP they’re using in the various sections of the datasheet.
Prototyping on FPGAs
Controller and Phy interface are exposed
ProFPGA system with daughtercards
Can’t run at full clock speed on FPGA
Digital vs analog simulation
Could someone (competitors) copy things?
As open as possible, being open where it provides value
Cost savings on the RP2040
Traditionally the “Southbridge” is the IO hub for computing, the Northbridge was the cache/memory (later subsumed into large CPUs)
2712 on RPi is 16 nm
This model of creating different generations of silicon but putting them all together is similar to chiplets but…on a PCB
There is a (hidden-ish) PIO in the RP1.
There will be more processing delays in RPI5 to deal with, but they won’t be noticable because Linux is already pretty not-real-time
Hoovering up more functions in one chip
Layout of connectors changed again
Pins are created to be well laid out on the PCB
RISC V foundation
The stack / ecosystem isnt as mature
James’ signature is under the USB3 connector
RPi5 is “the most raspberry pi raspberry pi” yet

#647 – Dave hanging with Fran Blanche

10 oktober 2023 | 66 min

#646 – Fan Fanboys

11 september 2023 | 64 min

#645 – Moving Down The Stack with Scott Williams

5 september 2023 | 82 min

#644 – Garbage Ninjas

28 augusti 2023 | 63 min

#643 – Calibration & Repair with Ian Johnston

22 augusti 2023 | 70 min

#642 – Sad Violins for Superconductors

13 augusti 2023 | 68 min

#641 – Power Transmission with Toby Robb

31 juli 2023 | 72 min

#640 – Software Defined Power Supplies with Werner Johansson

25 juli 2023 | 71 min

Welcome Werner Johansson of Qoitech!

Chris and Werner met when Werner gave a talk at HDDG in 2017
The talk focused on Xmega parts, which have a 2 Msps ADC
Qoitech is a Sony spinoff, where Werner was working on testing batteries on the cellphones.He had previously also worked on automation during linux mainline work.
Serial port control is an important thing when doing automated testing
CDB assist
PSOC5-LP has a CPLD in it
The Otii Arc was the first product from Qoitech, it’s a 2 quandrant power supply. They started in 2015/2016.
Chris asked if Werner had previously had used the Keithley 2306
Field testing is an imporant area for the Otii product line. “Measuremenets on the go” are easier with the extruded case form factor.
No computer will give you USB PD output power of more than 15W. Test equipment would benefit from a full 200W
Analyzer (Twinkie?)
A hub might be possible
USB Extended Power Range (EPR) will allow 240W
Are you sure you should plug that into your computer? Reminder about the OMG cable discussed on the show with MG
New EPR at 48V has specific shape for arcing
When designing a power supply for tattoo machine, it could only weigh half the weight of the cable (64g)
Software defined buck boost was discussed on CNLohr episode
Digital control is easier to get stable than analog because of programmable delays in the pipeline. You need to measure how long it takes to get the output to “show up”
Audio project real time jam sessions
The new product from Qoitech (that Chris got to see at Embedded World in 2023) is the Otii Ace
PJRC convinced Werner to check out the NXP RT106x family (instead of RT105x)
Otii is working on battery stuff
Arc has been out since 2017, but was limited output voltages 500 mv – 5V
Ace came out recently and goes up to 25V at 5A
3 isolation domains in Ace – chassis, banana jacks, expansion ports
Want resistor on low side for coloumb counter
Can stack Aces up to 200V
Dealing with RFI when different domains
Increased sample rate
8 simultaneous sampled ADCs
Turns readings into audio signals for RT1060, which allows data to stream easier
There is one reference voltage driving everything in the design, they send frequency spike across gaps to all isolated sections using RF isolators
Hard time getting the RT1060 parts during shortage
Battery stuff
Stepping through the battery internal resistance
Edging into the world of SMUs
Building a curve
Replaying battery data
Battery emulation
Continuous integration testing
Syncing to firmware
Battery aging
Devices running on coin cells
Cycling and automated testing and see it degrade over time
Thinking of batteries as impedance devices
Batteries having a passivation layer
“Low power” means different things to different people
Teardown of battery emulator
Low power is less than 200W
Qoitech equipment has been used in testing and production, including “in-the-loop” testing
“Generational degrade” when using previous versions of the product to validate new versions of the product. Instead they have a NIST traceable DMM in the loop
Chris mentions ever calibration shop has a Fluke calibrator. Apparently the HP 8753 wasn’t available in EU because of RoHS.
To learn more about Werner and the Qoitech team, check out the Otii Ace page

#639 – Daaaamn We’re Duuuummmb

17 juli 2023 | 64 min

#638 – Building AR Headsets with Aedan Cullen

9 juli 2023 | 69 min

Welcome, Aedan Cullen!

Chris first learned of Aedan from his 2022 Hackaday talk about building an AR system
AR is “Augmented Reality”, but that term is different depending on the company / headset (think “magic leap” vs “google glass”)
Got into AR because of robotics, he had be doing software around SLAM and CV
Interacting with objects in 3D space
The first board he was working with was the Jetson TK1
Magic Leap’s “Lightpack” had a Tegra in it
Apple’s new Vision Pro is more like VR with passthrough (and creepy eyes!)
Being able to wear an AR unit all day
Resolution matters
What is it worth spending power on in a headset?
The previous rev used the AllWinner D1 RISCV and can support one camera
Which way should you point a camera on a pair of glasses?
MIPI DSI outputs and DSP processing
Lots of SIPs available for high density designs
Octavo makes SIPs out of other companies’ silicon.
Jason and Robert from BeagleBoard talked about Octavo when they were on the show
ECX337 from Sony needs 10V
Torex power modules helped save space too by being stacked on top of the inductor
Sony uses LVDS (FPDlink) and not MIPI
Offloaded processing to a phone or computer
Power
Wi-Fi vs bluetooth
New goal is to minimize power during processing, now it’ll be efficiency around WiFi and Display
With OLEDs you can selectively turn on pixels
Goal for the battery is 8 hours for “all day”
What is Aedan’s “requirements space” and what’s driving it?
Cost has become a concern for new boards
Using an assembly house to have one known-good assembly board
What’s on the new board?
- The new display has MIPI DSI
  - The display doesn’t support 2 lane DSI out of the box
  - Displays are sometimes configurable in terms of how many lanes with registers
  - What do the lanes refer to? Each pair (“Data lane”) is a differential pair
  - Most displays will do 4 lanes (8 conductors) at 1Gbps
  - “Giganibbles per second”
  - Silicon backplane with OLED on top
  - ViewTrix
- The processor is the NXP iMX RT500
  - “This is design is made for Garmin”
  - Aedan is coding it in Zephyr
  - Drivers are in MCUexpresso
  - DCnano display driver in Zephyr
  - no GPU driver in Zephyr
  - 2D GPU in the chip
- WiFi module is the same as the past rev, the Si Labs WFM200S
  - Sending compressed data over the WiFi link
- Mechanical
  - Tweaking displays and 3D printed mounts
  - Prism
  - Flex cables
  - XReal / NReal
  - Using your brain as the combiner
Zach from Voidstar
Aedan just went to the Augmented World Expo in May. “No one was wearing an AR display around the conference”
Vision for the future
Follow Aedan online
- GitHub
- Twitter

#637 – CH32V003…fun! with CNLohr

25 juni 2023 | 75 min

#636 – Discovering Cursed Connectors

19 juni 2023 | 65 min

#635 – Low Power Connected Devices with Andrea Longobardi

5 juni 2023 | 77 min

Welcome Andrea Longobardi of AL2tech!

Andrea is a consultant in the HW / FW space, based out of Italy.
Chris met Andrea when he was transitioning to consulting and he joined the consulting forum.
Andrea comes from a family of engineerhing, His father is an EE who made PCBs at home but kept it from the kids
He worked at ST Micro designing drivers for server disk drives
If you lose power, the arm will crash into the platen. So when power fails, you use the energy in the motor to backpower the arm.
Didn’t like being pigeonholed and he wanted to get into apps engineering
Moved to Maxim, which he knew about because of their sample program
Working in automotive space: harsh environment and dealing with things like:
- Load dump
- Cold crank
- Low power during shutdown
Dealing with customers on last minute basis
Went abroad to the UK and worked for ARM/PA Consulting
Chris asked about the engineering culture in Italy/UK
Lot of focus on theory
“With the internet you can become an expert very quickly”
AL2Tech is Andrea, his brother Allessandro and a lab assistant
Had been back at Maxim focused on low power, connected devices
What’s it like working with a sibling?
Finding first client as a consultant:
- Networking with people on linkedin
- Looking at job openings and offering part time work
- Did it while building up the company
- Showing side projects (air quality sensor + BLE) since he couldn’t talk about his work at chip companies
It worked when a small company took a chance on him
FAEs were big companies, didn’t get access to the smaller company engs
Building test boards to learn new things (for the Joulescope), like a custom front panel
Gas monitoring is an area of focus for AL2tech
The device is battery powered, sitting on the meter.
Certification is critical: the certifying body is looking at schematic / layout and making sure nothing heats past the point of igniting gas.
Zone 0, 1, 2
Conformal coating
Why not put everything in Resin? Cost
Volume correctors for gas monitoring
For billing, they lean on PV=nRT
Internal product at AL2Tech is the Elektra
There is a CO sensor that caches data and sends over NFC and BLE
It detaches from a shirt with battery, but a reed switch disables power when not connected (so it can be washed)
Using the shirt to attract people and talk about capabilities
Embedded World helped expand outside of Italy
Other proejcts
- Rain Vision
- Tauanito Sensors
Find Andrea on LinkedIn
Check out al2tech.com to learn more about the company

#634 – The CAN bus can! with Dr Ken Tindell

30 maj 2023 | 69 min

Welcome Dr Ken Tindell of Canis Labs

Ken heard episode #631 where Chris was talking about a Noisy Rude Bus and he objected. Stringently (it seems Ken has since pulled down the posts, but they were in good fun)
Chris had been planning to talk about Ken’s recent awesome post about CAN hacking and cars being stolen, so he asked Ken to be on the show!
CAN was invented to reduce weight in car cable harnesses, which were increasing rapidly with more electrical features being included.
CAN vs LIN
CAN was expensive, but LIN is cheap because it’s bit banging the protocol from a microcontroller
There are bridges to go between CAN and LIN buses.
Modern cars have 20-100 ECUs (controllers), but it depends on the features the car has. But that’s not just microcontrollers, Ken estimates that could be as high as 700.
Chris and Ken both had dealth with Philips / Freescale / NXP / Motorola as silicon vendors in the automotive space
How does a tiny microcontroller get data onto the bus?
Prioritized traffic
CAN indentifier field has priority baked in
Bus works like a giant AND gate where the lowest address wins
11 bits
How to unwind CAN traffic
Packing signals into CAN frame
Tools to reverse engineer
Protocol decoder for sigrok
CAN HG
250kb is slow
CAN bus bandwidth
There is Ethernet in cars now, especially with more and more cameras
Bandwidth vs latency
Addressing through a gateway
Atomic broadcasts means you know that each device has processed it
Protocol hacking
Trucks aren’t OEM based so more vertically integrated
SAE J1939 standard in trucks
If say Toyota develops the CAN messages, DBC files decode everything.
But manufacturers don’t publish them, so some car messages are reverse engineered
Accessories bus
Who has access to DBCs?
Diagnostic systems
OBD2
CARB
CAN is physical ISO 11898
CAN XL has IP packets, so you can use wireshark
Ken has written about wireshark
CAN 2.0, CAN FD
Devices on a bus are normally all bare metal or RTOS because of the timing requirements
OSEK standard
Embedded system abstraction
Dealing with the magnitude of decisions making in the automotive industry
Chris asked about whether self-driving will happen in 5 or 20 years? (ie. does he agree with Chris or Dave). It was the latter, sadly.
Autonomic Cars podcast with Dr Phil Coopman

The Amp Hour Electronics Podcast

Chris Gammell and Dave Jones' voices span the chasm of thousands of miles each and every week to speak to each other and industry experts about where the field of electronics is moving.

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