Otaniemi Flying Finns jumping on board the FreeEMS wagon!

[Oskar]

Had a issue with jimstim today.

Slapped it together and tried to look at the tach signal on our scope.
But... we only got a super noisy ~400mv signal.

2h later (after finally going through the wiring diagram and figuring out how it should work) we jumpered the pull up voltage and hooked up 5v power.
Works perfectly.

Some very poor documentation though. Assembly is documented very nicely, actual usage isn't.
I know it's mostly intended for use with MS... but still.

[jbelanger]

I'm always open to constructive criticism and willing to improve the documentation or even better yet willing to include contributed text and/or pictures. However, as you mention the documentation (and the JimStim itself) is mostly targeted at Megasquirt users so things like having to provide 5V are irrelevant in that context. I don't want to confuse a part of the 95% of the JimStim users in the hope of maybe helping a few of the non-MS users.

Having said that, I'm more than happy that non-MS users can use the JimStim so I may add a section specifically for them with the first item being that the 5V needs to come from an external regulated source. If you (or anyone else) has suggestions for this please let me know.

By the way, I've received feedback from a few people on the web site content and it ranges from useless to very complete and easy to follow. So i guess it depends on the readers point-of-view and how successfully they've assembled and used the JimStim.

Jean

[Fred]

That threw me off briefly too, but as a MS user I knew that it supplied power to the outside world for sensors. FreeEMS will also supply power to the sensors so will be similar in this respect, it is only really during dev that it is an issue. I probably posted something similar ages ago, but I can't remember. The site is pretty good overall.

Potential improvements :

The tach inversion section could do with a description of what inverted and not inverted actually consists of.

The table of wheel modes could explicitly mention that you definitely get the second signal if you choose a mode that has one.

Actually, the pull up stuff is documented :

The tach signal will need a pull up if the MegaSquirt's tach circuit used does not provide it (such as the V3.0 standard tach circuits). You may apply one using jumpers on the header pins shown in the picture below.

Perhaps just say that it is fed 5v from being plugged into the MS. If you say that anyone could work out from that that they need to supply their own otherwise.

I have to admit though, I didn't RTFM when I built mine :-)

Fred.

[jbelanger]

Thank you for your comments/suggestions. All good points that will be added. And that's a good way to bring in the fact that the 5V comes from MS. This made me think that I can emphasize that if someone wants to test things up, they have to know that they won't have a 5V source unless the JimStim is connected to the MS.

I should add that there is a testing/troubleshooting section which is not very elaborate but does explain how to test the LEDs and tach signals. And if you read through this you will understand that there is no 5V supply on the board since the steps call for connecting the 3.3V rail to the 5V while warning people to do this only when disconnected from the MS.

And I remember you saying something about the 5V supply but I don't remember if it was posted here or in a private conversation.

Jean

[Oskar]

We figured out today that we will be very close to (or over) the max 16 analog inputs of the 114pin package.
We also ran out of PWM outputs. We need 8 and where thinking about using two more.

Hmm, well hopefully not much will need to be done in code or off-chip.

[jbelanger]

Depending on the needed PWM frequency, it could be done in software either in the main code or in the Xgate. In the latter case though, you'll need to deal with programming the thing.

Jean

[jharvey]

I've been toying with the thought of using a Pluto FPGA board to increase IO capabilities. Don't tell Fred, but I've also been dreaming of adding the flashy board for on board oscope. Perhaps I should draft up a schematic that includes the FPGA, if only I knew what the CPU pinout were going to be....

http://www.knjn.com/?pg=info&src=FPGA-RS232 for the low cost FPGA,

http://www.fpga4fun.com/Hands-on_Flashy_USB.html for the FPGA oscope.

[Fred]

if only I knew what the CPU pinout were going to be....

:-(

[jharvey]

We figured out today that we will be very close to (or over) the max 16 analog inputs of the 114pin package.

Perhaps I should call attention to the template folder in the posted KICAD files. Sounds like you may have a series of schematics with small differences between them, if so, you may find the modular approach I took, can reduce work time, as well it increases consistency. I know it saved me a pile of time, and decreased my errors quite a bit.

I did the modular approach because there are many circuits that are very similar. I simply made one template file, then wrote a script to copy it several times with a new name. For example, the injectors are all the same schematic, with differnt designator numbers. This was handy because if I wanted to change something like a property for a symbol, I simply changed it once on the template schematic, ran the scrip and it was updated on all the injectors. Preventing me from having to change it several times.

The general design flow for this included me posting one schematic for the injectors which we then all talked about and had input on. Then when we were happy with it, I used a script to copy this one file into several injectors schematics. This allowed the group to focus on a smaller set of data, then I was able to go off and crank out a bunch of work. Also, if someone wanted 4 cyls instead of 6 cy's, the could modify this script and remove the extra cyls. Creating thier own version.

I call this a modular design because it allows someone else to use sub parts of the assembly to make thier own. Kind of like you're snapping modules together. For example if you like the ignition and injector schematics, but you want 2 of each not 6, and perhaps you want 5 aux ouputs not 3, ect ect, you can change the script, to create the modules you want. Then snap them together at the top level drawing. You can also create your own modules and include them via use of the top level drawing.

Any how, if you have any questions, feel free to ask. Just thought I'd note the templates and modular design.

[Oskar]

We're now almost done with the electronics hardware. (lots of nice stuff)
Time is getting really tight to get everything done in a reasonable way to FS, but we should be able to just get there.

...although due to a unrelated matter we might not be allowed to even run at FS.