The OV-D20 radio-club in Berlin-Hohenschönhausen
Posted by lekernel in Geek collectives on January 31, 2012
Located close to the north-west border of the city, far from the popular districts, the D20 “Ortsverbände” of the national amateur radio club is certainly one of the most active grassroots tech clubs in Berlin.
As with many amateur radio clubs, the first thing you notice is that the average age is high. And they know how to appreciate vintage equipment. We can find, for example, a neat exhibition of electronic glassware.
And how about this “Made in DDR” transceiver?
The electronics lab comes with a mix of old (but does such stuff really get old?) and more modern equipment. Do not miss the SMD tools at the right – which were refreshing to see after I have been called “totally crazy” for hand-soldering a 0402 component on top of another in a well-known Berlin hackerspace. Phew, some people really need to catch up with technology.
There can be very interesting things being built there, such as this modified TV antenna that can now be used to… talk to AMSAT satellites and the ISS (yes, the space station) on the VHF band, using for example the APRS digital protocol. So… if you’re growing sick of being told about mediocre computer-controlled plastic extruders and microcontroller+LED kits, pay them a visit. It’s probably going to be worth the rather long travel time.
TDC core test results
Posted by lekernel in Misc projects on December 16, 2011
The test results for the FPGA time to digital converter (TDC) core are available from OHWR. Except from one problem which I believe is due to external signal integrity problems, the core worked well on the SPEC. From these tests, the 2-sigma precision is +/- 52 ps.
Observing internal FPGA signals
Sometimes, when debugging some firmware or hardware, it is necessary to see how the internal state of a chip changes in response to external signals.
With microcontrollers, this can be accomplished by adding code that toggles some pin that is then used for debugging, and watching that pin with an oscilloscope. Such a pin can also serve as sophisticated trigger, e.g., to capture some input signal only when an error is detected.
With M1, we can do the same, e.g., make LM32 or Navre toggle an I/O under software control. But we can do better: we can also route “hardware” signals directly, without involving software.
Here are three ways to do this:
- Change the Verilog to properly route the signal to the output pad. This is nice and clean but has the following disadvantages:
- need to run the full build process for each change of taps,
- need to edit the sources (and remember to undo all the changes once the problem is fixed),
- the signals need to be propagated step by step up the module hierarchy (*), which means a lot of small changes in many files,
(*) Verilog should support also direct references that “jump” the hierarchy, but this doesn’t seem to be properly implemented in the Xilinx tools.
- The pros just edit the FPGA with a WYSIWYG editor (Part three shows how to route signals to a pad). What I don’t like about this is that it’s not script-friendly. I’d also suspect that the changes are lost or at least in danger when re-synthesizing.
- Like above, but edit non-interactively. This is an experimental hack I’ve now implemented.
Read the rest from the Milkymist mailing list…
Announcing MIDI-USB support for Milkymist One
Milkymist One with Faderfox LV3
We are currently working on a software upgrade that will allow USB MIDI controllers such as the Faderfox LV3 to be used with the Milkymist One. The update will be compatible with all existing Milkymist devices, and will be installable easily.
Right now, you can already use traditional MIDI devices to control Milkymist One visuals. The update will make it possible to use those MIDI devices that only provide USB connectivity as well.
Milkymist One software updates
Software updates are available for the Milkymist One. This update mainly fixes a number of bugs – if you experience freezes or other issues, install the update, and let us know if you still have problems (devel at lists dot milkymist dot org).
Updating is easy – just connect the M1 to the Internet (booting it with the Ethernet cable connected to a network with DHCP should do, or use the system settings to configure the network) and then press the first push button (labeled L) for a few seconds. It should display this:
Update in progress
Then, power off and on again your M1. The “About” dialog box will display the new versions (Flickernoise 1.0 + SoC 1.0.1):
New versions
SoC Milkymist: le développement logiciel en pratique
Cet article a été publié dans Linux Magazine 130 (septembre 2010) et est disponible sous licence CC-BY-NC-ND. Depuis, la situation a évolué. Il existe un portage OpenWrt automatisant de nombreuses manipulations décrites dans l’article. Une partie du chargeur d’exécutable et de nombreux bugs Linux ont été corrigés. QEMU ne nécessite plus de patch et la version 0.15 supporte directement Milkymist. Enfin, les Milkymist One sont disponibles à la vente et viennent avec une version bien plus aboutie de Flickernoise ainsi que tout un “packaging”.
Le numéro 124 de février vous a donné une présentation générale et assez théorique du System-on-Chip (SoC) libre Milkymist. Maintenant, nous allons nous orienter vers la pratique en détaillant les différentes opérations nécessaires au développement de logiciels fonctionannt sur cette plate-forme: installation des outils de compilation, construction d’un noyau Linux compatible, compilation d’applications et utilisation de l’émulateur QEMU, pour finir avec la configuration d’une carte de développement FPGA permettant de prototyper le SoC et le déploiement du logiciel sur cette dernière.