Posts
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Emacs and python.el
I use Emacs for most of my programming. I do a lot of programming in Python. So quite naturally I use Emacs for a lot of Python programming.
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Strömmätning
Jag har byggt en ampere-meter.
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Simulating Kicad schematics with Spice
I've written a couple of Python scripts to be able to simulate Kicad schematics with Ngspice and display the results using matplotlib.
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Capturing ADC data into DDR memory on the SDS7102
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
I'm finally able to capture data from the ADC directly into the DDR2 memory connected to the FPGA.. -
The fast buses on the SDS7102
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
I take yet another look at the fast buses in the scope. -
Source code for my SDS7102 port
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
Just to let you know that I have put my source code up on github. -
The analog frontend of the SDS7102
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about the analog frontend. -
The SoC bus on the SDS7102
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about the bus between the FPGA and the SoC. -
Capturing data from the SDS7102 ADC
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about capturing data from the ADC. -
SDS7102 Front Panel
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about the front panel of the scope. -
More SDS7102 FPGA pins
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about finding the remaining pins of the FPGA. And a call for help. -
Finding SDS7102 FPGA pins
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about using the FPGA itself to find out how the pins on the FPGA are connected. -
Finding SDS7102 GPIO pins
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about using code running on Linux to find out how the pins on the SoC are connected. -
Another look at the hardware in the SDS7102
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about all the things I've discovered about the hardware in the scope so far. This is the post to read if you want to see how everything in the scope fits together. -
SDS7102 OS Disassembly
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about disassembling the original firmware on the scope. -
The SDS7102 File System
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about reverse engineering the file system on the scope. -
Disassembling the SDS7102 bootloader
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about disassembling the bootloader on the scope. -
Linux on the SDS7102 Scope
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about how to get Linux to run on the scope. -
Hacking the OWON SDS7102 Scope (Part 2)
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This post talks about using JTAG to extract the firmware from the scope. -
Hacking the OWON SDS7102 Scope
A series of posts about reverse engineering the OWON SDS7102 oscilloscope.
This is an introduction to the scope with a first look at the hardware inside. -
Playing around with Jupyter
I’ve written some python scripts that talk to a BG7TBL signal generator and to my Tektronix 11801B oscilloscope. I can set the output frequency for the BG7TBL and then dump the measured waveform from the scope over a serial port or GPIB. With a bit of signal processing (FFT and some calculations) it’s possible to calculate the frequency and amplitude of the signal. Combine the signal generator with the amplitude measurements and you have a poor man’s network analyzer. It’s very slow, it takes a couple of minutes to do a sweep of 400 pointer, and it’s probably not very accurate, but it’s good enough to be useful.
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An almost-GHz active differential oscilloscope probe (Part 3)
This is part three of a series about building a active differential oscilloscope probe. Part 1 covered why I wanted a differential probe and the design of it. Part 2 covered actually building the the probe. The probe had much lower bandwidth than I had hoped for but it was still useful.
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An almost-GHz active differential oscilloscope probe (Part 2)
In my last post I described how I had simulated and designed an active scope probe and sent off the design to a PCB manufacturing house. If you haven’t read part 1 yet you might want to do that before continuing.
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An almost-GHz active differential oscilloscope probe
I wanted to probe a PCB at work to see how a ~500MHz differential clock was behaving. My trusty 100MHz oscilloscope was no use, it was too slow to see anything and unfortunately I couldn’t quite justify buying a $3k differential probe for my faster scope just for this. There are a bunch of DIY probes to be found on the internet but none that seemed to work really well. But then I thought “how hard can it be?” And thus starts this story.
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STM32F405 pinout spreadsheet
I’ve been using the STM32F405 for some of my projects. To make it easier to figure out which I/O pins I wanted to use for a certain project I created a spreadsheet with the possible alternate functions from the data sheet. The first sheet lists pins grouped by which port (PA, PB, etc) it is connected to. The next sheets lists pins ordered by pin numbers for all packages. Two more sheets only list the the pins present on the LQFP64 and LQFP100 packages.
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Running wxPython 3.0 on Linux Mint 17.2
I wanted to try out wxPython 3.0 on my machine running Linux Mint 17.2. Unfortunately, Ubuntu 14.04 LTS, that Mint is based on, only has wxPython 2.8 in its repository.
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Scratching an itch - rdesktop
I’ve been using rdesktop for quite some time. It’s a nice little program that can connect to a Windows machine using the remote desktop (RDP) protocol so that I can view the Windows screen on my Linux machine.
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Kass marknadsföring
Jahopp, nu började jag få mail från netauktion.se igen. De håller på med oönskade massutskick av mail med reklam för deras auktioner. Det jag tycker är lite roande är att varje mail avslutas med följande text:
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Getting the HTML source from an Android WebView
On and off I’m working on writing an Atom/RSS feed reader for Android. The feed reader is using an Android WebView to display the contents of a feed and to be able to debug some issues I had I wanted to be able to view the HTML source for a page.
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Halloween Milling
A few years ago I bought a cheap CNC mill from China. It’s actually a “CNC engraving machine”, but it’s actually robust enough so that it can mill wood and soft metals such as aluminum. Ḯ’ve been using it to build electronics prototypes, both for milling PCBs and for milling enclosures.
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Lifehacking
I’m a nerd, I find technology fascinating. In my career I’ve done just about everything with computers, from being a system administrator changing disk packs for backups to writing J2EE code or designing and building simple electronics. And just about everywhere I’ve seen fascinating stuff that I would like to learn more about and have had ideas about interesting things that I’d like to try out. But over the last few years I have been working full time or more and really have not had the time nor energy to do that.
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Creating Android menu icons with Inkscape
I’ve spent a few weeks writing a feed reader for Android, Weader and wanted to have nice little menu icons for every possible choice. Android comes with a bunch of standard icons in the SDK and it’s probably a good idea to use them to begin with so that an application will fit the standard Android look. But I needed a few more icons.
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Weader - A simple atom/rss feed reader for Android
Ever since Google cancelled Google Reader I’ve been looking for a new feed reader. I haven’t found one I like so far. I’ve tried Feedly, Newsblur, Tiny Tiny RSS and a bunch of others but none of them really did what I wanted, most tried to do too much, all I wanted was a simple and lean feed reader for Android that I could use while commuting to work. Then I found FeedGoal. I didn’t like the user interface FeedGoal either, but it is open source and had a fairly nicely partitioned backend which would probably be possible to reuse.
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Coaxial Cables
It’s been a long time since I wrote anything here so I guess it’s time to write something. A warning though, this post will talk about coaxial cables, so those with a low tolerance for boredom can stop reading now.
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NFC, vad är det?
Jag har just skaffat en ny Android-telefon med stöd för “NFC”. NFC betyder “Near Field Communication” eller på ren svenska trådlös överföring av information mellan två prylar som är nära varandra. På svenska brukar man annars prata om beröringsfria kort. Ett exempel är kortet som används för att åka med Stockholms Lokaltrafik.
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The Gnome 3 Disaster
Yes, this is yet another rant about Gnome 3. Others have written about it before, but I just read the announcement that Gnome 3 Fallback mode will be dropped and just need to vent my feelings somewhere.
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Persistent device naming on Fedora 17
In their infinite wisdom the people behind Fedora 17 decided to remove the udev scripts that provided persistent network names. I kind of liked those scripts so I just created a small RPM package which just contains the files from a Fedora 16 installation.
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A TDR scope
I’ve gone and bought an old oscilloscope, a Tektronix 11801B. The 11801 is a 20 year old design, but it still has some pretty impressive specifications: 50GHz analog bandwidth and takes a sample in 10fs (yes, femtoseconds). With the scope I got a SD-24 sampling module which only has 20GHz bandwidth but it also has a pulse generator to make TDR measurements.
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SD Sniffer part 2
I’ve finally had time to play around a bit more with the SD sniffer I designed a few weeks ago. I started placing all the active components on the board and also got to curse myself for choosing the tiny, tiny, SC70 packages for the comparators. The SC70 package is tiny and the components were quite tricky to solder, mostly because I don’t have access to a stereo microscope any more. But it all worked out in the end.
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SD Sniffer
I need to debug a problem with a SD bus. I have previously used a USBee SX with a custom firmware to sniff the bus and save a trace of all the SD signals to the hard drive so I could analyse them offline. This works fine up to about 30MHz but then the USBee runs out of bandwidth to the host PC. But the SD standard version 2 allows the bus to run at up to 50MHz and also tightens the electrical requirements for the SD bus, limiting impedance and capacitance so that the bus reliably can run at such high speeds. So for modern cards the USBee can’t keep up and the long wires to the USBee can introduce a bit too much loading and deteriorate the signals so much that the SD card will no longer work.
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Restaurang 88, Kista
Kineser i allmänhet gillar numerologi, talet 4 betyder otur medans talet 8 betyder tur. Det märker man t.ex. på telefonnummer, att köpa ett kontantkort med fyror i numret är jättebilligt medans kontantkort med ett par åttor i kan kosta flera hundra RMB.
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Pong Asian Tapas, Kista
Jag har börjat jobba i Kista. För att vara ett ställe med så mycket folk så är jag inte speciellt imponerad av lunchrestaurangerna, de flesta käns som skolmatsalar för vuxna och antingen är det rätt tråkig husmanskost eller så försöker de sig på avancerade saker som burritos och misslyckas fatalt med det.
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Reverse Engineering, Part 2, Schematics
In my last post I described how I wanted to reverse engineer a RFID card reader. Read that post first if you haven’t.
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Reverse Engineering, Part 1, Introduction
I like to do strange stuff with hardware, especially in combination with Linux. For example, I once bought an Acer n30 PDA. The PDA ran some variant of Windows CE so quite naturally I started poking at the device to see if I could get Linux to run on it instead. A few weeks I actually managed to get Linux to boot on it.
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Restaurang Trattoria La Casa
I fredags ville jag bjuda ut min mor på födelsedagsmiddag och vi hamnade på Trattoria La Casa som finns på Långholmsgatan i Hornstull precis där Västerbron börjar. Det är en restaurang som jag snubblade in på första gången i vintras. Jag hade egentligen tänkt gå någon annan stans, men där var det fullt, så då kom jag ihåg den där italienaren som jag knallat förbi flera gånger och tänkt ta en titt på. Det jag åt den gången var deras lamm och det är också vad jag rekommenderade åt min mor.
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DHL - fortsättningen
Jag hade ju en del strul med DHL i fredags. När jag ringde jag DHL och undrade vad de höll på med så talade ju kvinnan på telefon om att jag inte skulle få mitt paket på utsatt tid. Så jag undrade när de tänkte leverera och hennes svar var tvärsäkert “mellan 13:00 och 16:00 på måndag”. Så idag tänkte jag gå på lunch lite tidigare än jag brukar, vid 12, bara för att vara helt säker på att vara hemma till 13:00. Fast jag är nog lite misstänksam av mig ibland, så jag tog takeaway från Thai-kiosken tvärs över gatan, så jag hade uppsikt mot parkeringen utanför mitt hus hela tiden. 12:30 dök DHL-killen upp. Tur att jag är lite paranoid, för annars hade jag sluppit få mitt paket idag också.
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DHL och hemmakontor
Nu blev jag påmind om något som jag hade förträngt. Jag har lite elektronik på väg till mig som jag ska jobba med. Paketet är skickat med DHL. Så i morse klockan nio ringde jag DHL för att kolla så att det inte är något strul eftersom jag jobbar hemifrån och det är en vanlig hemadress som paketet ska till. Jag säger att jag satt en lapp väl synlig på ytterdörren där det står “paket till Weinigel, ring 0706681254” så att det verkligen inte ska bli något strul.
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Restaurang Rosen och sjuttitalet
Jag måste börja med att säga att jag inte alls är förtjust i sjuttiotalet. Jag tycker det mesta retro-modet är skitfult och jag är ju född på sjuttiotalet så jag är inte det minsta nostalgisk om det årtiondet.
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Lunch på restaurang Platinis
För mig har alltid restaurang Platinis på Hornsgatan vid Zinkensdamm varit en sunkkrog och inte en speciellt skoj sådan. Men nån gång det senaste året har de fräschat upp lokalen rejält och nu på sistone när jag varit hemma mycket så har jag varit iväg och käkat lunch där ett par gånger och blivit mycket positivt överraskad.
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Nu har även jag blivit med en blog
Jag har varit rätt sugen på att starta en blog. Inte för att jag har så mycket att skriva om för det mesta, men ibland vill jag dela med mig av lite datanördigheter jag håller på med eller skoj saker jag varit med om.
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