sigrok + UNIX = Awesome! - part III - Fun and Games with gpsd

So here I am hanging out at the local hacker space in Richmond. We, the group that meet up every Tuesday evening are small, yet perfectly formed. This evening Paul (MØTZO), a friendly radio ham, and co-founder of our group brought along an interesting device to encode GPS location data in APRS (Automatic Packet Reeporting System) packets. These packets are fed into to a VHF radio transmitter which transmits the signal at 144.8 MHz. A network of receivers, run by amateur radio operators receives the packets, and streams them over the internet. An interesting device indeed.

Tonight we were just playing with Paul's GPS board, which contains a U-Blox Neo 6 GPS receiver. As with most GPS receivers simply powering it on is enough to make it emit coordinates encoded in NMEA 0183 sentences transmitted over UART at 9600bps.

These are trivial to receive with an fx2-based logic analyzer and sigrok-cli:

$ sigrok-cli --driver=fx2lafw --config samplerate=50k \
    --continuous -P uart:baudrate=9600:tx=0 -B uart=tx

With the UART protocl decoder and the ASCII binary output, we can see the NMEA sentences:

Here we can see that we're locked on and receiving coordinates. "cat -v" is used to protect the terminal state from being clobbered by any errant binary data being emitted.

Yawn. Let's make this more interesting.

There is a very interesting package called gpsd. This is a GPS location server than can connect to various types of GPS devices, and can serve the position information over the network. And best of all, thanks to the power of UNIX pipes, we can feed the data from sigrok directly into it:

$ gpsd -N <(sigrok-cli --driver=fx2lafw --config samplerate=50k \
    --continuous -P uart:baudrate=9600:tx=0 -B uart=tx)

There are a variety of gpsd clients available. There's a nice ncurses based client, gpsmon:

And best of all KDE's Marble integrates with GPS. Here we see Marble, showing a live stream of location data captured by the fx2lafw firmware, decoded by sigrok, handled by gpsd, plotted by Marble on OpenStreetMap map data. Pretty freetarded:

New protocol decoder: rfm12

libsigrokdecode now supports yet another protocol decoder, rfm12.

This one decodes the SPI-based protocol of the HopeRF RFM12 and RFM12B wireless FSK transceiver modules. These devices can transmit and receive in the 433MHz, 868MHz and 915MHz bands (depending on chip).

Thanks a lot to Sławek Piotrowski for contributing the decoder (as well as an example file for sigrok-dumps)! We've also added a small test-case in the sigrok-test repository to be able to keep track of any potential regressions that might occur later.

Manson HCS-3xxx series programmable power supply support

We're happy to announce that libsigrok now supports the Manson HCS-3xxx series of programmable power supplies (PPS).

Thanks a lot to Matthias Heidbrink for improving the driver and extending it to support more models in this series! See the model overview for more details. There are various rebadged versions sold by Conrad/Voltcraft, PeakTech, and probably other resellers.

All power supplies in this series have one channel only, featuring various voltage/current/power combinations though. They're connected to the PC via a (built-in) USB-to-serial IC (e.g. the SiLabs CP2102 in the Manson HCS-3202). A relatively simple ASCII-based protocol is used to communicate with the devices and control them.

You can control the power supplies e.g. via sigrok-cli like this:

 $ sigrok-cli -d manson-hcs-3xxx:conn=/dev/ttyUSB0 --show
 manson-hcs-3xxx - Manson HCS-3202 with 1 channel: CH1
 Supported configuration options:
    output_current: 0.000000
    output_current_limit: 0.000000
    output_enabled: on (current), off
    output_voltage: 3.390000
    output_voltage_target: 0.000000

 $ sigrok-cli -d manson-hcs-3xxx:conn=/dev/ttyUSB0 --samples 2 -O analog
 CH1: 3.300000 V DC
 CH1: 0.000000 A
 CH1: 3.380000 V DC
 CH1: 0.000000 A

 $ sigrok-cli -d manson-hcs-3xxx:conn=/dev/ttyUSB0 --config output_voltage_target=5.0 --set

 $ sigrok-cli -d manson-hcs-3xxx:conn=/dev/ttyUSB0 --config output_enabled=yes --set

The code was tested on the Manson HCS-3202 and the Voltcraft PPS-11815. Please let us know if you are able to test any of the other devices the driver is supposed to support, and/or whether you experience any issues.

 

New protocol decoder: spdif

libsigrokdecode now supports the spdif decoder.

The Sony/Philips Digital Interface Format (S/PDIF) is a (nowadays standardized in IEC 60958) digital audio protocol that is used in various devices and supported by a number of ICs, such as the TI PCM2707 and many others.

A short description of the protocol is available on the respective wiki page, along with pointers to further reading.

Thanks a lot to Guenther Wenninger for contributing the decoder!

Yokogawa DLM2000 series oscilloscope support

We're happy to announce even more hardware support in libsigrok. It now supports the Yokogawa DLM2000 series oscilloscopes / mixed-signal scopes.

Thanks a lot to Soeren Apel for writing the code and testing on a Yokogawa DLM2054! We're especially happy about this new driver since it's the first Yokogawa device at all that we now support.

The DLM2000 series features 2 or 4 analog channels, and the 4-channel models can alternatively capture 3 analog channels + 8 digital ones. The scopes sample at 2.5GSa/s and feature a bandwidth of 200MHz-500MHz (depending on the model) and up to 250 Mpoints of memory.

The DLM2000 devices seem to specifically target various industrial uses and include some interesting analysis/reporting features like a "history search" and "replay" function, enhanced trigger facilities, Go / No-Go functions, a power-supply analysis feature, and more.

While the device can do some simple decoding of certain digital protocols such as SPI (apparently those are optional add-ons to buy), you can of course widely broaden the range of protocols by using the sigrok protocol decoders on the PC side.

The devices can be connected to a PC via either USB (USBTMC protocol), Ethernet (LXI), or GPIB. The protocol itself is SCPI-based, have a look at the source code if you're interested in this kind of stuff.

It might be possible to support the DLM4000 series with some minor updates of the driver at some point, probably even others. Patches and testers for that are highly welcome, if you own such a device please let us know!

 

 

 

A new, better Openbench Logic Sniffer

The venerable Openbench Logic Sniffer has long been a popular logic analyzer: it's cheap, capable and entirely open source. Unfortunately the project was abandoned long ago, so no new features were ever added. The one major problem with the OLS was always its limited available memory: it has no memory chip on the board, using only the small amount of memory available on the FPGA to store samples. Its slow, PIC-based USB interface made it impossible to use a streaming architecture, like the fx2lafw devices.

Enter the Saanlima Pipistrello: an inexpensive but very capable FPGA development board. It has a newer Spartan-6 FPGA, 16MiB flash, 64MiB DRAM and an FTDI-based USB interface. It also comes with lots of ports: HDMI, audio, Micro-SD, PMOD, and 48 GPIO pins in a Papilio Wing configuration. The board is completely open source: schematics and Eagle design files are available under the CC-BY-SA 4.0 license. The board itself sells for $155 at the Saanlima Store.

A buffer wing is also available. This protects the FPGA with 5V-tolerant transceivers. Highly recommended: I destroyed many unbuffered pins on my OLS board long ago.

The original OLS verilog code couldn't use DRAM for storage, so the Saanlima folks adapted it. Proper edge triggers were also added to the FPGA code, something that was cumbersome on the OLS. They also contributed a sigrok driver, which has been merged into libsigrok. Thanks, Magnus!

New protocol decoder: nrf24l01

libsigrokdecode has gained support for a new protocol decoder recently, the nrf24l01 PD.

Thanks a lot to Jens Steinhauser for contributing the decoder, as well as a bunch of test files that we're using for some automated decoder tests (and that you can use to easily try out the decoder as well).

This decoder stacks on top of the SPI PD, decoding some higher-level commands used by the Nordic Semiconductor nRF24L01(+) 2.4GHz RF transceiver ICs.

A short description of the chip and its protocol and pins is available on the respective wiki page, along with pointers to further reading.


New major release of various sigrok components

Hi everyone! We're very happy to be able to announce a major new, coordinated release of:

There have been a lot of improvements in pretty much all parts of the code, including more supported hardware, more protocol decoders, more features, various bugfixes, better portability, improved GUIs, and lots more. Many thanks to all the contributors who helped to make this happen!

libserialport

Starting with the libsigrok 0.3.0 release, all libsigrok drivers that talk to serial ports are using the cross-platform LGPL3+ libserialport library now (which has its first release, 0.1.0, today). This also helps to improve the Windows support for sigrok.

The library was written by Martin Ling (thanks a lot!) and supports a number of OSes, including Linux, Mac OS X, Windows, and others. Supported features include port enumeration, opening/closing ports, setting port parameters (baud rate, parity, and so on), reading/writing/flushing data, etc. etc. You can take a look at the API docs for more details.

Note: libserialport is completely independent of sigrok, i.e. it can be used by various other open-source projects without any problems, too.

libsigrok

The most interesting libsigrok changes for users will likely be the new hardware support, so here goes:

There have also been a number of other (infrastructure) changes and improvements, though:

  • We added support for channel groups (multiple channels of the device, that share some properties and are configured together).
  • There's a generic SCPI backend now that drivers can use, supporting various transports: serial ports, USBTMC, TCP/RAW, TCP/Rigol, VXI, and librevisa.
  • The session file format (*.sr) has changed and its version was bumped to 2.
  • There's improved Windows support now for serial port and USB based devices, though it's partially still experimental! Please checkout the current list of known Windows issues, since there are some problems e.g. with the popular FX2 based devices (bug #343) and the Openbench Logic Sniffer (bug #205). Feedback, bug reports and patches are highly welcome!
  • Various API improvements were also done, to allow for some of the new features and to ease future extendability. You can take a look at the API docs for more details.
  • And of course there was a huge amount of bugfixing, as usual.

See the NEWS file for the full list of changes.

libsigrokdecode

Same deal for libsigrokdecode, most people will probably want to know which new protocol decoders are supported:

  • guess_bitrate: Guess the bitrate/baudrate of a signal
  • ir_nec: NEC infrared remote control protocol
  • ir_rc5: RC-5 infrared remote control protocol
  • midi: Musical Instrument Digital Interface
  • parallel: Parallel synchronous bus decoder
  • rgb_led_spi: RGB LED string decoder (SPI)
  • xfp: 10 Gigabit Small Form Factor Pluggable Module
  • z80: Zilog Z80 microprocessor disassembly

The protocol decoder backend has also received a bunch of new features and facilities in this release:

  • Support for annotation rows (groups of annotation classes to be shown together).
  • The new OUTPUT_BINARY facility allows PDs to output decoded data in various (file) formats (e.g. I²S output in WAV format, USB output in PCAP format for Wireshark, LCD controller output in PNG format for viewing, and so on).
  • The new OUTPUT_META facility allows PDs to report certain data points or events to the frontend, which can be used for various post-processing and statistics purposes (e.g. simple counts, average/mean values, min/max values, and more).
  • The protocol decoder API has changed, the API version is bumped to 2. Decoders using the old PD API no longer work with this library release.
  • A large amount of PD fixes have been done to improve the usability of all PDs when used with GUIs (long/short annotations for zoom-dependent display, corrected annotation sample numbers, use of annotation rows, and so on).
  • Various API improvements were also performed to allow for all the new features. You can take a look at the API docs for more details.
  • And of course all PDs and the library code have received quite a few bugfixes, as usual.

See the NEWS file for the full list of changes.

sigrok-cli

sigrok-cli (a command-line sigrok frontend) now depends on both libsigrok >= 0.3.0 and libsigrokdecode >= 0.3.0 and supports all the new features of the libraries, including channel groups, PD annotation rows, the new *.sr file format, plus the usual bunch of bugfixes.

The following changes have been performed for the command-line options:

  • The -g | --channel-group option was added.
  • The -M option (for PD meta output type support) was added.
  • The -B option (for PD binary output type support) was added.
  • The -p | --probes option was renamed to to -C | --channels.

There were also a bunch of improvements related to the (experimental) sigrok-cli Windows installer. You can download an (experimental) nightly build here: sigrok-cli-NIGHTLY-installer.exe. Any feedback, bug reports, or patches are highly welcome!

See the NEWS file for the full list of changes.

PulseView

PulseView (a Qt based sigrok GUI for logic analyzers, oscilloscopes and MSOs) has also received quite a huge amount of improvements and new features (thanks a lot to Joel Holdsworth!):

  • Support for protocol decoding (via libsigrokdecode) has been added, including support for annotation rows, multiple decoders in the same GUI window, support for stacking protocol decoders (e.g. I²C -> RTC8564, UART -> MIDI, or SPI -> SDcard) and lots more.
  • Support for loading and saving sigrok session (*.sr) files has been added.
  • Initial support for analog data sources (specifically oscilloscopes, e.g. the Rigol DS1052E) has been added.
  • The Windows installer has received a bunch of fixes and improvements, too. You can download an (experimental) nightly build here: pulseview-NIGHTLY-installer.exe. Any feedback, bug reports, or patches are highly welcome!
  • And of course there were quite a number of bugfixes, as usual.

See the NEWS file for the full list of changes.

sigrok-firmware-fx2lafw

This release of sigrok-firmware-fx2lafw, the open-source firmware for FX2-based logic analyzers, is only a minor bugfix release. It basically only fixes one bug which lead to the data pins not being tri-stated after an acquisition, but rather being driven.

See the NEWS file for the full list of changes.

 

Have fun analyzing your signals!

Windows support and installers

For a long time Windows support in sigrok was somewhat lacking and/or in the TODO state, but things have improved quite a bit recently.

While there have been both a working cross-compile setup based on MinGW (additionally based on the MXE suite of scripts) as well as working NSIS-based installer executables for sigrok-cli and for PulseView for quite a while, they weren't really all that useful.

Only very few devices used to actually work in practice due to portability issues and due to certain limitations in the way libsigrok was talking to USB-based hardware devices (e.g. various logic analyzers) and serial port based devices.

All of this has changed though. A major part of the solution and fixing was done by Martin Ling (thanks a lot!) by writing specific thread-/Event-based code for the Windows platform for allowing libsigrok drivers based on libusb to properly work on Windows (transparently, i.e. without requiring changes to the drivers).

The other part of the puzzle is the new LGPL3+ libserialport shared library, also written by Martin Ling (thanks again!), which is a portable, cross-platform C libary (that is completely independent of libsigrok, i.e. it can be used by various other open-source projects without any problems, too). So far, it supports Linux, Windows, Mac OS X, and some BSDs. More on libserialport in another blog post.

With all the above-mentioned improvements we're now providing daily-built, self-contained Windows installers for sigrok-cli and PulseView, that ship with everything you need (the executables and libraries, the protocol decoders, some firmware files, some example files you can use for testing decoders and UIs, the Windows Python 3 installer you need for running protocol decoders, the Zadig tool you need for switching devices to use the libusb driver, etc. etc.).

Downloads:

Please make sure to read the Windows wiki page, it contains some more information related to drivers, firmware files, current device status, and so on.

We've tested the basic functionality on Windows XP and Windows 7 (and we don't expect any issues on Windows Vista or Windows 8 either), but we're happy to hear any feedback you may have and/or issues you might encounter.

 

New protocol decoder: ir_nec

We're happy to announce that libsigrokdecode now supports yet another protocol decoder, this time: ir_nec. The PD has been contributed by Gump Yang, thanks a lot!

This is a decoder for the so-called NEC infrared (IR) protocol, a rather widely used protocol for remote controls (for TVs, VCRs, and lots of other things).

The protocol is based on a pulse-distance encoding, i.e., a 1 bit is encoded by a pulse and a long pause after that, and a 0 is encoded by a pulse and a short pause after the pulse.

The "payload" basically consists of an 8-bit address (which is a number that is supposed to be unique for a certain vendor / device), and an 8-bit command / code which identifies which button was actually pressed.

The 8-bit address is followed by the inverted 8-bit address, the 8-bit code is also followed by its inverse. This is (or can be) used for error checking on the receiver side.

You can read up on the protocol details in various online resources.

When the proper definitions for specific remote controls are added to the PD, it can also decode the actual remote control button in a more human-readable form e.g. "Matsui TV: Mute" vs. "Address: 0x40, command: 0x10", see screenshot for an example.



 

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