ELECINF344/381

Interactive web site of Télécom ParisTech's ELECINF344/ELECINF381 Robotics and Embedded Systems classes (a.k.a. ROSE, 2012 session).

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First life signs of our board

Yesterday we got our PCB soldered, next step is obviously to test it. First happy thing was that the board didn’t get on fire when powering it on.

We created a new ChibiOS project that will be the base for our code. To do things the proper way, we also made a new board folder, which is specific to our PCB. It specifies all the settings of the various GPIOs on the µC, such as the alternate functions.

One minor problem we hit, is that stm32f4 isn’t supported in the openocd build that is running on lab’s desktops, so we had to build master branch of openocd’s git. Thanks to Sam, that was an easy task. After that, the JTAG just worked out of the box.

Once everything was setup, first functions we’ve tested is powering on/off the red led, and the serial port. Testing them made us realize that the serial port has actually been wired the wrong way, TX on the usual RX pin of the micromatch. Hopefully, we aren’t the only group to have failed on that, so we can use SaMoRa’s serial cable :-) .

Another mistake on the schematics we found out, is that one encoder plug isn’t properly usable: one pin is on a timer, while the other one is on another timer. This is no big problem, since it can easily be done in software, and that it seems really unlikely we’ll use encoder.

Yet another mistake on the PCB, is that the plugs aren’t named, so we need a map to know what function is on what plug.

Anyway, despite the various problems, all the features tested are working, so that’s great news !

Pierre-Hugues Husson

Tutobot – Schematic and Software

Hello,

Our PCB is 99% finished, the others 1% is about the decoupling capacitors. SmartFusion documentation recommends the use of capacitor of several different values to filter different frequencies with a small resistance for each frequency. It recommends using capacitors multiple of 10, for example eight capacitors of 0,01µF, four of  0,1µF, two of 1µF and one electrolytic capacitor, to maintain a certain capacitance and resistance in some frequencies.

However, we couldn’t find anything about how to calculate the numbers of capacitors to use in our PCB. In the Evaluation Kit, seems that they tried to use as many capacitors they could fit near the VCCs of the µC.

We worked in the software too, finally programming the SmartFusion in Linux is working. We played with the UART.

This week, Gabriel and me, we will be developing the software, Thalita will be responsible of the decoupling capacitors and routing as this can not be divided in several tasks, but of course we don’t forget that we are a team :)

 

Tutobot’s Team.

Helen Fornazier

Tutobot – Schematic 90% ready

Hello,

Our schematic is almost ready, we are working in VCCs, GNDs and respective capacitor and inductors, considering analogic and digital signals in the SmartFusion according to this document, we almost finished it today, this should be finished by tomorrow morning.

All the others schematics are ready, we are just waiting the LT3979 and the battery connector to be added in the Expedition library.

The biggest inconvenient of SmartFusion is that informations are spread in several different documents,  there is the general datasheet, the documentation of the FPGA, the doc of the MSS, another doc of the Analog, SmartFusion Board Design Guidelines, Board-Level Considerations, and there are others. This kind of division can be a good organization, but sometimes the information we are looking for is broken in several pieces, each piece in a different document.

 

Helen Fornazier