The Amp Hour

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**The Amp Hour**

The Amp Hour is a weekly conversation about electronics and the people who design them.

Latest Episodes:

An Interview with Craig J Bishop Dec 02, 2019

Show notes

Welcome, Craig J Bishop!

Craig designed and built the Gameslab, which is a custom gaming platform built with a Xilinx Zynq part (XC7Z035). (Update: Craig has been posting more about the Gameslab on his site here)
Bought reballed chips on PCBs. They were actually a $1200 chip he got for $80.
Episode with Ryan Cousins
There is apparently a kit for counterfeiting Xilinx chips
National lab has a pdf on how to detect counterfeits
Digilent Zybo
Craig built the board on the JLC 6 layer process at 210x100 for each board. $150 for 5 PCBs.
DDR3 chip was .8mm pitch
Using stack up to calculate impedance/prop delay
Used an excel sheet to track delay and skew for nets, since KiCad can't track delays between layers
FPGA on chip delays are also stated in the datasheet and need to be accounted for.
Running Rust on STM32L0, on kernel modules in A9, applications / games
Sense resistors with instrumentation amps going to the ADC to measure each rail's current draw.
BQ24250 chip for charging with configurable registers
Zynq doesn't necessarily need the bitstream programmed first. Instead the A9s boot first and can load the bitstream.
Every game brings its own hardware
Can put the Gameboy hardware into the fabric!
Craig doesn't like verilog, so he uses a higher level language called SpinalHDL. It is a fork of Chisel, which is based on Scala.
Each of the above languages are strongly typed. Loosely typed means you can convert between data types, like in C.
"Verilog is becoming the assembly language of FPGAs"
ZipCPU
AXI bus
Most designs need to reimplement different hardware blocks. But there are libraries in Chisel, which can implement things easier.
Vex Risc V
Created a frame buffer for the LCD and some 2d graphics acceleration on the Gameslab.
Learned to program to make PC games. This was part of the idea behind the Gamesphere project as well.
PIC18F452 in a 40 pin DIP
Used AT91R4000 for the game sphere
Andrei LaMothe wrote the book "The Black Art of video game console design"
Cypress dual port SRAM
Craig's first "big boy job" was working for a a neighbor up the street starting a semiconductor packaging company (Tim Olson)
Deca Technologies was opening a Wafer Level Chip Scale packaging fab in the Philippines.
After iphone came out, there was a lot of demand for low profile complex chips.
Raspberry Pi photon problem
Added a "squishy" layer to the silicon, and then exposing certain parts of the silicon to the interconnect.
The graphics problem was that they wanted to make the chip bigger but the silicon smaller
EWLB from Infineon looks like a plastic wafer.
Can put two chips next to each other
There was a paper about the subject (has the image Chris and Craig were discussing during recording).
Sometimes the parts are placed 30 microns to the left, which is not good for the substrate they are placed upon.
Can get really expensive PnP machines but they go slow.
The microscope would spit out X, Y and rotation, but it scales with chip complexity, such as when there are two chips.
Needed to do traces between them
Craig's job was to take the output and do some autorouting between them.
Feature sizes were 1 micron
Package design looks like PCB design
Cadence sells System in Package designer but is really Allegro with different plugins.
Can people do their own SIP?
Craig thinks that design will move towards more SIP
Split die architecture
Split it into a few pieces: This will help improve yield and flexibility, as well as modularity.
Chris asked about Chiplets, a topic that is championed by Dr Subu (sp?)
Chiplets are going to do interconnect in silicon, not plastic
Example is BLE and micro
Adaptive alignment
Craig gave a talk at KiCon about how Autorouters work and how they have been improving.
Not your grandpa's autorouter
Freerouting is nice and available but it's not the latest
TopoR
Moving towards interactive design (P&R), but Craig thinks it should go the other way.
Generative design would be better
Dave Vandenbout's SKiDL talk
Craig was briefly interviewed by Piotr and Alvaro at KiCon
Find Craig on his personal site where he is documenting his projects (craigjb.com) and also find him as @craig_jbishop on Twitter.
Check out the Phoenix 3H (hardware happy hour) if you're in the area!

The Tiny Lab Movement Nov 24, 2019

Show notes

WeWork problems
Chris is gearing up to buy a boat anchor (VNA) discussed in episode 462
Leaving stuff on the bench
Dave thinking about downsizing, possibly starting "The Tiny Lab Movement"
You have to focus on one thing in a small space
Mr Carlson's Lab has a bunch of Patreon-only videos for learning about electronics
Dave talked about flex PCBs this past week. It's not a flex tutorial, but one might be on the way eventually.
Former guest Dan Hienzsch has started a site called Manufacturing Reports, where he reviews PCB fabrication houses. Dan was also recently on the Macrofab podcast.
TG-130 vs TG-180
Former guest Ted Yapo expanded on the 8 GHz scope he discussed on the show during his talk at Supercon
Select on test
Chris gave a talk on RF at Supercon
A highly automated warehouse in the UK burned down after a rogue robot lit on fire
Comparing logic elements between part vendors
Reasons to put FPGA into a product
Goofing TX and RX
Dave and David are trying to fit everything into 32K chip on STM32
Mike Harrison's talk about LEDs
GreatScott explaining USB C (and USB PD)
Yageo is buying Kemet

Thanks to Ales Kladnik for the image of his father’s cramped lab

Stories from Supercon 2019 Nov 18, 2019

Show notes

This week, Chris recorded the show with 3 different guests at the Hackaday Superconference. This is an annual hardware conference with about 500 attendees in Pasadena, CA.

Guests on this week’s show:

The conversations focused around the conference badge and its differentiating feature from many other electronic conference badges: It was all implemented on a Lattice ECP5 FPGA using RISC V cores and was in a GameBoy form factor. Most interestingly, it was all done using the Symbiflow open source toolchain. We called out other guests we've had on the show before while recording:

Contributed after the show aired: Matt Venn sent in links about the PicoRV32 and a reminder of the Symbiotic EDA youtube channel. Read more about the conference badge on Hackaday.

An Interview with Ryan Cousins Nov 11, 2019

Show notes

Welcome, Ryan Cousins of Krtkl!

Don't forget to fill out the 2019 listener survey! Closes November 22nd
Krtkl's embedded/FPGA platform is called Snickerdoodle, which is based on the Xilinx Zynq.
Ryan and his team got started working in the medical field working on mechatronics, doing the same stuff over and over again for customers.
Saving time from development risk
Example where "wires" on a base board were hooked up
Greg Davill's fantastic bodge wiring
The Snickerdoodle has a low end and high end product option:
- Snickerdoodle One is 115
- Snickerdoodle Black is 245
piSmasher
Customers are doing up to 10K units per year.
Started the company about 5 years ago
Biggest area of interest is in video space
Running up against the edge of what the part can do
Since they are targeting industrial customers, Krtkl have to keep supporting older boards
Challenge has been keeping community engaged
There are other Zynq modules out there, like the Zed board ($450). These are more like traditional dev boards.
Crowdfunded 4 years ago on Crowdsupply
Ryan was surprised how critical (ahem) people were of the product.
Chris checked and he said something nice on the interview with Clint Cole
Software layer is an important differentiator
Krtkl supported Ubuntu Linux out of the box
Working on streamlining the IP, they might eventually have an "app store" for reconfigurable logic IP blocks.
Custom peripherals need still need drivers in Linux
"Getting linux to run on this thing was more effort than building the hardware"
Zynq book
Pynq, which shows how to use Python for FPGAs
How are customers using this product?
- Dual core system running 6 axis arm
- Remote sensing, needed to be lower power. They put the high power module in the FPGA in deep sleep mode.
- Company doing pinball accessory
- Smart retail applications
There are really two main categories: mechatronic or high bandwidth (things like video)
It's a mix for how many are using linux
Krtkl is consulting on 2-3 development projects at any given time
"If you want to get a consulting business off the ground, start a crowdfunding campaign"
Still waiting on one line item from the crowdfunding campaign to have shipped out 100% of orders.
Check out the company at krtkl.com and their main product at snickerdoodle.io
Read more about the strife during the crowdfunding campaign on their update page of Crowdsupply
Reach out to Ryan by email
Read more about getting started on the Snickerdoodle campaign
"It'll only get better with time"

An Interview with Ted Yapo Nov 04, 2019

Show notes

Ted is a fan of soldering AND stock photography This episode is sponsored by Rohde and Schwarz. Check out AskAnEngineer.us for more info about their value line test equipment.

Ted is a lifelong electronics hobbyist
He studied engineering physics in college.
Full color faxes were a thing in Japan but never took off elsewhere.
After working on scanning equipment, he moved on to doing networking work.
He also did some consulting after Cisco.
Mid-way through his career, he went back to graduate school.
Wrote a paper about finding telephone wires using LIDAR for helicopter pilots.
Transitioned into AR, sort of like Projection Mapping. It was used for architectural daylighting simulation.
Going back to school is tough for what you remember. Ted had to relearn linear algebra. He recommends using Gilbert Strang's lectures, which gave more context.
After school, Ted did consulting with a few partners, mostly New England.
Ted got started posting to Hackaday with 2016 HaD prize.
His first entry was the "Diode clock", which utilizes the fact that diodes act like switches for RF when you pass DC current through them.
"Upping serendipity quotient"
Using diodes as an AND gate
Using pin diodes for a doppler radio project
1n4007 can act as a crude pin diode at certain frequency
Built digital clock that uses diodes for the counters
Assembly instructions - 46 boards!
Power supply is around 6 MHz
One of his other popular projects is the Tritiled, which helps figuring out where things are in the dark
Based around the idea of tritium lights
Modern LEDs are extremely efficient at a certain current
Droop happens at higher currents
The 8 GHz sampling oscilloscope is a more recent project
Research came out of the diode clock
Schottky diodes for sampling
Tek S4 sampling head 14.5 GHz
Diodes can switch in 10-15 pS
Stroboscopic effect
Equivalent time sampling
Tek 11801 from 1989
Nyquist still applies
Verifying on the bench is difficult
Paper from picosecond pulse lab
Jim Williams using an avalanche diode or a step response diode
Looking at RMS error
Another architecture 1975 by SP McCabe
Using a fast comparator to sample waveform, similar to a successive approximation ADC
ADCMP582
That's the time base calibration
What will people be able to build with an 8 GHz scope?
Using it to measure transmission lines on PCB boards
Using Time Domain Reflectometry
Ted has a splitter TDR head
Tracking generator + Spectrum analyzer = Scalar network analyzer
Rigol came out with cheap spectrum analyzer, DSA815, Ted got one of the early units
Tracking generator outputs signals that are the same as the frequency on the spectrum analyzer
Ted gave a talk about this at last year's Hackaday Superconference
There is no phase in an SNA
SNAs are harder to calibrate
Paper was about how to do two measurements to compensate for errors in the generator
Chris has a friend doing Python scripting on test equipment via their ethernet jacks.

You can find Ted on Twitter, Hackaday.io and as a writer for Hackaday

KonnectorPanik Oct 27, 2019

Show notes

Chris has been making antennas on a mill and measuring them on a VNA.
Past guests Pete Bevelacqua and Jeff Keyzer offered their help about the
Hardie Pienaar was nice enough to simulate the antenna Chris cut to show what it should look like. It matched the reality well (this is the cover image for the episode).
Alan Wolke made a great video about how to use Smith Charts
Chris had to buy a bunch of n-type connectors, leading to a term he called "KonnectorPanik"
Apple is moving some of its manufacturing out of China
Looking up the term "student destinations" for different schools shows where students go on to work and how much they make. We looked at Carnegie Mellon's recent reporting.
We heard about Kong.cash from Paul Gerhardt. It's a "physical cryptocurrency" based upon the Etherium blockchain (Chris edit: trying to hold it together to get to the good parts here).
There is a flex PCB with UV printing and on-board security chip that allows users to validate transactions. The ATECC608A holds private keys, and enables a bunch of internet connecte devices these days.
"The chips are a keypair that identify the bill to an escrow contract. That contract holds a value timelocked for 3 years. You can check that the value is still there via NFC and even interface to it via the electrical connectors."
Dave did a (non-crypto) wallet review
Dave also did a teardown of (not just) a millivoltmeter. The hinged design and metal cans over each section were beautiful.
Dual display AC millivoltmeters
OnShape bought by PTC
Openscad, a project started by past guest Clifford Wolf
Flash memory is bricking Teslas
Someone posted about a "chip printer" on Kickstarter. What the heck is an n-type filament?
There's a $5 FPGA board coming to Seeed studio (h/t to Frank Buss) based upon the Gowin FPGA from Alcom

An Interview with Trammell Hudson Oct 21, 2019

Show notes

Welcome Trammell Hudson!

This episode is sponsored by Rohde and Schwarz. Check out AskAnEngineer.us for more info about their value line test equipment.

Trammell likes to gets things to the Proof of Concept stage, and then "hand off the keys to the repo"
Matthew Garrett quote, (paraphrased) "I don't think I'm very good with computers, I'm just bad at knowing when to give up"
Taking good notes is a big part of Trammell's process, which resulted in the site linked above.
Magic lantern firmware
Started from CHDK firmware, which is GPL
Starts with looking at the updates that the vendors ship, then getting code execution
Toggling the firmware out on an LED
Disassembler tools:
- Hopper
- Ida
- Ghidra
He's currently playing with Ikea smart bulbs and dimmers
Gave a talk at Hack in the Box about "time of check, time of use"
Project called Linuxboot, replaces x86 firmware with linux software
Trammell's newest project is the SpiSpy
Logs all the flash memory accesses
Tool was built to speed up firmware dev that revealed security hole
Built with the ECP5
Gave a talk about SpiSpy at CCCamp
Hard to emulate the real time flash, since you have to serve up a response in 1 clock cycle
DRAM is too slow, so it's necessary to start the row/column reads before they have all of the bits
Retrocomputing
- PDP11
- Mac SE
Former guest of TAH Fabienne did the ROM dump scarves
Archive.org documents old file formats
Teensy4
Scanlime had a tiny85 act like an RFID
Trammell replicated and extended this work
RFID doesn't transmit back from the passive device side, it just shorts the coils together
PSK31
13 hz of bandwidth
SpiSpy project had a bus contention problem, scope saved the day
Vector stuff
Used dual DAC to drive the XY
Former guest Todd Bailey also did vector work on the VEC9
CRTs don't move instantaneously
Vector generation needs to model the magnetic drivers
Added tunable parameters to the screen driver code.
Later CRTs had color
Had a write up in POC | GTFO
Worked on Robots with others at NYC Resistor
Puma Robot Arms were reverse engineered and turned into shuffleboard robots
Using a scope for the quadrature decoding
Trammell is a full time Security Researcher
Thunderstrike was a vulnerability that allowed code insertion via the thunderbolt cable on the mac.
Linuxboot replace proprietary boot software in servers and other hardware with linux
Independent bios vendor
Bulk of the code comes from intel
Unix wars of 80s and 90s
OEMs do "not invented here"
Gave a talk about it at 34c3
Build your own custom firmware for the lamps
Check out all of Trammell's projects on trmm.net
Find Trammell as @qrs on Twitter or Mastadon

The image is a capture from a 1 kilopixel Cyclops sensor that Trammell re-projected through an oscilloscope (link)

Boat Anchors Oct 13, 2019

Show notes

Chris has almost finished reading Eccentric Orbits and has been working on satellite comms in the meantime.
Flat earther documentary on Netflix, Behind The Curve
Satellite internet is en vogue again, with Elon Musk launching Starlink and pasts guests like Maarten Engalen (Hiber)
5G distances are pretty short (depending on the implementation)
Discontinuing 3G in Australia
GSM wasn't a big factor yet during the timeframe of Eccentric Orbits (1993 - 2002ish)
Shahriar did a review of the Siglent SVA1032X and Chris is getting a demo unit soon!
The HP8753ES was another one on Chris' watch list, but it's a "boat anchor" (heavy piece of test equipment)
The TDS220 was one of the earlier scopes that changed the standard for how much space it took up on the bench top.
Dave advertises when there are auctions on the EEVblog forum "Buy / Sell" section. This is a good way to find an auction house to sign up for future notifications.
Gerbers were a standard format used for photo plotting. The aperture was how wide the light beam was opened as it passed across the board.
Chris has a "residency" where he gets to try out a Bantam Tools machine. He talked with MG about milling circuitboards a couple months ago.
The Dragonfly is another machine that supposedly "prints" layered PCBs. It would work well as a super crisis option, but probably not for most PCBs.
The plan is for Chris to mill out antenna shapes, like those shown in TI App Note 58 (AN058)
Dave and David have been working with the Richtek USB C processor
Seeed Studio has some new boards coming out with a RISC V Bumblebee core, made by Giga Devices. The part number is super confusing!
ARM is allowing custom instructions to be added to the Cortex cores, ostensibly because they're feeling pressure from the RISC V option.
In Dave's new video about LED lights flickering, the part he was looking at was marked the same as a datasheet, but had a completely different implementation.
Chris released Getting To Blinky 5.0 videos
A writer at Digikey tore down and reviewed a $17 power supply
The device we were discussing on episode 460 was a process meter (Dave made a video about it). It ended up selling out very quickly.
Dave is a doctor-certified tight ass (hence knee problems)
We are doing our 2019 survey! Please consider filling it out, we will have prizes for people randomly drawn for filling it out.

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Thanks to Stew Dean for the photo of the anchor

An Interview with Jonathan Georgino Oct 07, 2019

Show notes

Welcome, Jonathan Georgino of Binho!

The Binho is a USB host adapter targeted at manufacturing floors, but also can help people quickly talk to devices using i2c, serial, SPI and GPIO.
There are a couple of options out there for manufacturing: Some are robust and expensive, others are hobbyist
Using scripts and adapters for production line programming
Career started at GE in St Marys, working on a CAN sensors
Got a Saleae logic analyzer, wrote to Mark and Joe, went to go work with them.
Mark and Joe were on episode 237 of The Amp Hour
Helped to design the Logic 8, 8 pro and 16.
Jonathan took away that products should be a pleasure to use, easy to understand
Making it accessible in multiple ways
Mark recently talked to Limor about the Saleae
After Saleae, Jonathan went to go work at the Wonder Workshop (WW)
Other consumer Robot startups having a hard time. We talked about Anki on episode 441.
WW focuses on the educational market, where you need to be prepared for 1 year sales cycle and need a curriculum for the teachers who will be using it.
Blockly or Scratch to program the robots
Variables are tough for kids to understand (or big kids, like Chris).
When designing for the educational market, need to design for robustness and compliance testing
Testing comes out of the IEC standards, with different ones for each country.
Partnered with toy manufacturer in China to make the robots.
Jonathan was only EE up until production
Dash has 12 different PCBs, with one that has 3 processors and 2 SPI flashes on board.
Blockly is an open source project from Google
"Changing careers is the best way to learn and grow"
After WW, Jonathan moved to Zola, who are doing off grid for African countries.
He got to visit Tanzania and see the product in action. There wasn't as much needed on the EE side of things.
Then he joined Pi, now Spansive
They were working on a wireless charging device using A4WP, banking on new phones adapting it as a standard (it wasn't)
The experience in China manufacturing was that there are devices available but they are low cost and have janky UI.
Most popular on the market are from Total Phase
Can connect to Binho using Python API or any application that can pass in ASCII characters
Can hook into any of the existing tools
Some people are using a Raspberry Pi for testing
Under the hood it's an m0, with protection for overcurrent
Also have a GUI
Built in Xojo to be cross platform
Use pip to install binho host adapter
Jonathan advises you to put your pins onto the board the first time your board is made
Continuous integration for firmware
Rigol has python libraries, as does the Saleae. These might be python on top of GPIB.
Check out Jonathan's personal site and the Binho site.