Uwe Hermann's blog

Hung-Chang DSO-2100 supported

We're happy to announce that libsigrok now supports another PC oscilloscope, the Hung-Chang DSO-2100 (also sold under different brand names such as Voltcraft or Protek).

This is a 1999-era parallel-port based device with 30MHz analog bandwidth and 100MS/s samplerate.

The hardware (see also PCB shots) is somewhat non-trivial, it uses a QuickLogic FPGA, an Analog Devices DSP/microcontroller, some SRAM and Harris/Intersil ADCs. It also has some other properties or quirks you might be interested in.

The driver was contributed by Daniel Glöckner, thanks a lot!

Since this is the first parallel-port device in libsigrok, the build system also gained detection support for libieee1284, a cross-platform parallel port access library that the driver uses.


New protocol decoder: Microchip MRF24J40

We're happy to announce that libsigrokdecode supports yet another new protocol decoder: mrf24j40.

This PD decodes the SPI-based protocol of the Microchip MRF24J40, an IEEE 802.15.4 2.4 GHz RF tranceiver chip.

As usual we also have a few sample dumps in the sigrok-dumps repository, and a few test-cases in sigrok-test.

The decoder was contributed by Karl Palsson, thanks a lot!

KERN scale series supported

We're happy to announce that libsigrok now supports various weighing scales from KERN & SOHN GmbH.

The new kern-scale driver currently supports (and was tested on) the KERN EW 6200-2NM scale and all scales from the series which have the same protocol.

The scale can report the currently measured values (both unstable and stable ones) via the RS232 cable it ships with.

The protocol is a simple (14- or 15-byte) packet-based ASCII protocol containing the measured value, the unit (gram, ounce, etc.) and an indicator of whether the measured value is stable or not.

Support for other KERN scales with a different protocol can be added easily. Please let us know if you are able to test on other devices!

Usage example:

 $ sigrok-cli -d kern-ew-6200-2nm:conn=/dev/ttyUSB0 --samples 10
 Mass: 26.920000 g
 Mass: 26.920000 g
 Mass: 134.600006 ct UNSTABLE
 Mass: 134.600006 ct UNSTABLE
 Mass: 134.600006 ct UNSTABLE
 Mass: 134.600006 ct UNSTABLE
 Mass: 134.600006 ct
 Mass: 134.600006 ct
 Mass: 134.600006 ct
 Mass: 134.600006 ct


New protocol decoder: Stepper motor

Another protocol decoder that hasn't had an official announce yet is stepper_motor, a PD which decodes speed and position of a stepper motor.

The PD takes a "step" and "direction" pin as input.

You can select either steps or millimeters as unit for the decoder output.

As usual we also have a few sample dumps in the sigrok-dumps repository, and a few test-cases in sigrok-test.

The decoder was contributed by Petteri Aimonen, thanks a lot!


New protocol decoder: Jitter

libsigrokdecode has had support for the jitter protocol decoder for a while now (it is already shipped with the recently-released libsigrokdecode 0.3.1), but this hasn't been officially announced yet, so here goes.

The decoder allows you to retrieve the timing jitter between two digital signals. This can be useful for a number of things, e.g. finding jitter/delay between a sender and receiver (be it wired or over some form of wireless communication), or for debugging your firmware interrupt setup by checking how much jitter you have between multiple consecutive invocations of the interrupt handler that should in theory always be equally spaced.

We also added a small test-case in our sigrok-test repository so we can ensure that the PD works fine (and continues to do so upon changes).

This protocol decoder has been contributed by Sebastien Bourdelin, thanks a lot!

libsigrokdecode 0.3.1 released!

We're happy to announce that libsigrokdecode 0.3.1 has been released.

You can download the libsigrokdecode-0.3.1.tar.gz source tarball from sigrok.org/download as usual.

This is mostly a bugfix-release, the C library API was not changed. This means existing frontends that work with / are linked against libsigrokdecode 0.3.0 will continue to work just fine, without requiring relinking or recompiling.

However, some of the protocol decoders' output changed in ways which are not compatible with the state of the decoders in the last libsigrokdecode release. This means, if you're using any scripts to parse decoder output, or if you have any "private" protocol decoders that stack on top of one of those shipped with libsigrokdecode, you will have to do some adaptations. You're also encouraged to submit such decoders to be included in libsigrokdecode proper, of course!

In addition to all kinds of improvements and bugfixes in existing protocol decoders (PDs), you're probably most interested in what new protocol decoders are now supported (backported from git HEAD). So here's the list:

  • adns5020: Bidirectional command and data over an SPI-like protocol
  • am230x: Aosong AM230x/DHTxx/RHTxx humidity & temperature sensor
  • arm_etmv3: Decode ETM instruction trace packets
  • arm_itm: Trace data from Cortex-M / ARMv7m ITM module
  • arm_tpiu: Filter TPIU formatted trace data into separate streams
  • eeprom24xx: 24xx series I²C EEPROM protocol
  • jitter: Retrieves the timing jitter between two digital signals
  • mdio: Half-duplex sync serial bus for MII management between MAC and PHY
  • mrf24j40: IEEE 802.15.4 2.4 GHz RF tranceiver chip
  • nrf24l01: 2.4GHz transceiver chip
  • pwm: Analog level encoded in duty cycle percentage
  • rfm12: HopeRF RFM12 wireless transceiver control protocol
  • spdif: Serial bus for connecting digital audio devices
  • stepper_motor: Absolute position and movement speed from step/dir
  • swd: Two-wire protocol for debug access to ARM CPUs
  • tca6408a: Texas Instruments TCA6408A 8-bit I²C I/O expander
  • timing: Calculate time between edges

This adds up to currently 54 supported PDs in total.

Please check the libsigrokdecode NEWS file for the full list of user-visible changes in this release. As always, we're happy about bug reports, feature suggestions, comments about which protocol decoders you'd want supported next, or even better — patches :)

Happy decoding!

Maynuo M9812 now supported

We're happy to announce that libsigrok now supports the Maynuo M9812 digital load.

The driver was contributed by Aurelien Jacobs, thanks a lot!

It was written in a pretty generic way so that it probably also supports many of the other devices in the Maynuo M97 series of devices.

If you are able to test one of the other devices in that list, please let us know!

The hardware is attached via a (virtual) serial port and communication happens via a protocol on top of Modbus RTU (as documented in the user's guide)

There are also a bunch of teardown photos (plus links to the relevant ICs and their datasheets) of the device on the wiki page, if you're interested in that kind of stuff.

New protocol decoder: Avago ADNS-5020

We're happy to announce that libsigrokdecode now supports the adns5020 PD, a decoder for the Avago ADNS-5020 optical mouse sensor protocol.

The decoder was contributed by Karl Palsson, thanks a lot!

It stacks on top of the common SPI PD and decodes ADNS-5020 specific registers reads and writes.

There is an example file in the sigrok-dumps repository if you want to test the decoder, as well as a test config in our sigrok-test repository.


New protocol decoder: 24xx I²C EEPROM

It's been a while since the eeprom24xx protocol decoder was added to libsigrokdecode, but there hasn't been an "official" announce yet, so here goes.

The eeprom24xx PD can decode the I²C-based protocol of (almost) all 24xx series EEPROMs from various vendors.

Supported chips include for example the Microchip 24LC64 or 24AA025UID, the ST M24C01 or M24C02, the Siemens SLx24C01 or SLx24C02, and others. Various other chip families can be added relatively easily via chip spec entries in the decoder's lists.py file.

These ICs usually have only very few bytes of storage (e.g. 128 or 256 bytes), where the memory is organized into pages (the page size is e.g. 8 or 16 bytes). They usually support various types of accesses (command sequences) such as "byte write", "page write", "current address read", "random read", "sequential random read", "sequential current address read", and others.

Apart from a common command subset, some of the chips also support custom non-standard commands such as "set write protection" or "read write protection status" (on ICs that have write-protectable areas), and some others.

UNI-T UT372 now supported

libsigrok now supports a new device class, tachometers! The first supported device of this type is the UNI-T UT372.

It's a USB-attached device (uses one of the WCH CH9325 ICs commonly found in UNI-T gear) that can measure RPM and counts.

The protocol of the device (now documented in the sigrok wiki) was reverse engineered by Mike Walters, using a somewhat unusual and quite interesting technique. Instead of the usual method of sniffing the USB traffic and then staring at hex numbers until things start to make sense, he used the following method:

After a first quick look at the USB traffic it was pretty clear that the packets usually look something like this:


Now, instead of trying to figure out which bit and byte means what by looking at many of these packets, Mike instead generated his own packets that looked like the real packets from the UT372. He sent them to the vendor's PC software (via a custom-built "emulator" on a USB-enabled Arduino), which then interpreted and displayed the values and flags that it thought were sent by an actual UT372 device.

By randomly flipping bits in these packets and observing how the PC software's interpretation of the packets differed, Mike was able to figure out the individual protocol details a lot faster than using other methods.

Shortly after the protocol was known, Martin Ling wrote a libsigrok driver for the UT372 by hooking up a device-specific ut372 parser to the existing uni-t-dmm driver in libsigrok (which already handles the somewhat "special" CH9325 details).

Thanks a lot to Mike Walters and Martin Ling for their contributions!



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