Puma board for FreeEMS

[nitrousnrg]

I finished the routing, this is the setup so far:

* 12v general purpose outputs -> PP0,PP1
* Stepper -> PP2, PP3,PP4,PP5
* Fuel pump -> PK0
* 5v general purpose I/O -> PJ0, PJ1, PJ2, PJ3, PP6, PP7 (routed to the 40-way signal connector, with protection circuits)
* RPM -> PT0, PT1
* Ignition -> PT2, PT3, PT4, PT5, with hw selectable polarity. (note the wasted, PT6&7, wich could be extra freq inputs)
* injectors -> PB0, PB1, PB2, PB3, PB4, PB5, PB6, PB7
* ADC -> 12 channels available, according the Standard Document, so its vanilla-compatible. There is an extra thermistor input, extra thermocouple driver, and an extra general purpose analog input.

It has been already git-pushed, the DRC gave no errors.

The solder mask has been tweaked a little, and many components were moved a pinch to ensure there is solder mask around every chip (I was having many 4 resistor arrays, so close that there wasn't solder mask between them).
I still have to put vias to 4 pins of port A, but the DRC didn't allow me. I'll see what can I do without turning the DRC off.

Given its dimensions, its a ~50 dollar board at batchpcb, btw. I guess I spent around 110usd in components, maybe more. Having 8 P&H drivers costs around $50, but that could be avoided in case of choosing normal drivers.

If there aren't major things to work out, I'll start with the silkscreen soon.

[Fred]

Looks good so far! Keep it up :-)

[jharvey]

Is U33 in backwards? I would have to take a closer look at the datasheet, but the symbol implies the signal flow is going in the wrong direction.

Some comments that are a bit less critical include silk screen, vias or pads for unused MCU pins, and some random vias under those larger components to help prevent thermal expansion issues.

Another thought that might help make the first run more successful is to print out the board full scale, and place the chips on the paper to ensure the pads are close to right. I've seen some funky chip packages come through. If you have the parts, I'd recommend giving it a quick look before you place your order with the PCB house. Specifically I'd recommend taking a close look at any chip and any diode. Diodes often get larger than the silk screen shows, this often forces the surrounding components to get a bit pushed around.

When it comes to selecting the PCB MFG, have you taken a look at ladyada's web sight? You enter the board size and general specs, and it tells you the price you would expect to pay from a variety of vendors. I've confirmed a couple like BatchPCB and gold phoenix, they price noted by ladyada and the price I paid were very close to the same.

It's looking good, and getting exciting. Keep it up.

[nitrousnrg]

Is U33 in backwards?

haha, I spent like an hour to figure out how to use those gates symbols, and ended putting it backwards. There is a "do not show hidden pins" button at the left toolbar that should be turned off to see the power connections of some components. I also had big troubles with the power wires at the schematic, it was bridging 12v, 5v from reg 1, and 5v from reg 2. I removed the whole power thing, now they are just wires.

Last night I joined kicad-devel, and was happy to find out what they are planning: an eeschema rewrite, and OpenGL usage to improve the pcb 2D/3D drawing performance.

Another thought that might help make the first run more successful is to print out the board full scale, and place the chips on the paper to ensure the pads are close to right.

I already did some footprint testing, with a correctly calibrated printer. ICs looks good, and I'll watch out the diodes, you have a point there.

have you taken a look at ladyada's web sight?

Cool site, the board is 5.10x3.93in for those who want to try it. I'll make the prototype in buenos aires, otherwise the shipment will cost just too much.

Stay tuned

[Fred]

"5.10x3.93in" - Just because your continent is joined to their one, it doesn't mean you have to use broken measurements! :-p

100x130 for anyone that grew up in the 70's or more recently.

Marcos, what is postage like in the other direction, ie, out? If your shlt is correct, pin wise, I might need a few of these suckers to test with :-) Do you reckon you could supply a few with CPU and preloaded SM? or is it blank/complete only?

[nitrousnrg]

haha, I've put inches just to comply with Jared's page. I still can't imagine the size of more than 3 inches.

what is postage like in the other direction, ie, out?

It should't be a problem, I guess. It could be a little box, with a girl-ish pink knot over it saying "To the cutest girl/teacher/bird I've ever met". No one would care :P
Seriously, that won't be a problem. I'll ask some people about bigger packages, though.

I can supply whatever people want, once we have confirmed the reliability of this board. I could provide the bare pcb, a partially assembled pcb, or a complete board. It would be nice to have an online shopping feature, like a page showing the stock we have, and allow order requests. For example, the trough hole components in this board are meant to be exchangeable/optional, so the user could select which features and connector board it needs. Or buy a bare pcb/components too (isn't this DIYefi.com?). Its just an idea, I could take care of that myself.
In the argentinian forum you posted a while ago, I proposed discounts in exchange of documentation ;-) Many, many things can be done to improve the project growth, but the system reliability should be our flagship.

FYI, you can load the SM of an empty S12 with your adapt board. If you dare to buy and assemble all the SMD components, then you are ready to diy a puma board :-) Otherwise, just tell me. I'll have assembled and tested boards in stock (once the 2 prototypes are working, and I place the second and bigger digikey order).

And about the name... I'm declaring officially that this development will be known as the "puma board for FreeEMS", or just puma, or something like that. I'll ask you some things about the name changing:-), specially regarding the git repo.
Also, I wonder where should I put Jared's name in the project, this is just a fork of his previous work, and the license surely says something about it. Probably an 'acknowledges' text file for those who helped would be nice too.

[Fred]

What I meant was to get in on your first cut prototype, IF it conforms to what I believe it will need to conform to. You might find SeanK will want in too (and others?). Then we can help you debug and test these cards and give feedback and also develop more firmware on live engines using this hardware. Jared's original is another option, for sure. I'll have to review each when the time comes.

Does the design have a BDM port on it? I hope so. You can't load the SM onto a bare chip without a BDM though, and software for it, and I don't have one, yet. If your testing goes well, I'll build one of those too.

Do you have any provision for getting the balance of the pins out to another card? Some sort of header? How about a proto area like ms v3.0 board? How expandable will it be?

Fred.

[jharvey]

Also, I wonder where should I put Jared's name in the project, this is just a fork of his previous work, and the license surely says something about it. Probably an 'acknowledges' text file for those who helped would be nice too.

That entire derived work thing is a bit of a pain with GNU isn't it. I'm not worried about it. I prefer the MIT licence, however, Fred was fairly passionate to have it as GNU, so I made my stuff GNU. I would recommend you focus on getting development done, and less on the legal constraints imposed by GNU. I won't complain about it, and if someone else does complain, I'm sure you'll comply and resolve the complaint in short order. For now I'd like to encourage you to not fret it very much.

[Fred]

Jared, unless someone else commited to your project, you may relicense it as you wish. Also, I said TAPR for hardware, never GPL. GPL is a valid choice, though. Hell, you can even grant Marcos permission to all the rights of it and then he can do as he wishes with it. The ball is in your court. What you can't do is take existing work away from anyone with a copy. Not unless they are OK with it. I hope that makes sense.

[nitrousnrg]

Does the design have a BDM port on it?

yes, near the bottom left of the microcontroller.

If your testing goes well, I'll build one of those too.

Build a BDM? I think I saw somewhere an Adapt board acting as a BDM interface. I can't find that page now, though.

Do you have any provision for getting the balance of the pins out to another card?

Not sure about the balance meaning, but: this has to communicate with the connector board. So everything pass from one board to the other trough connectors. A 40-pin dip signal connector, and a couple of slightly bigger power connectors (I didn't decide which type in particular, but I have some preferences) are connecting the boards.
For the other cpu pins, I'll put unmasked vias to access them, at least for the important ones for testing. Don't count on having every pin available, just 4 of port a, some of port k, etc. If you want, make a list of your preferred pins for testing. I want to remove all of them eventually, I prefer to have ground planes instead of hacking connections. Right now there are 6 GPIO pins routed to the connector, and could be 8 or 10... its quite a lot.

How about a proto area like ms v3.0 board?

No, not in this board. The connector board is the right place to put a proto area, there is plenty of space there. It could come with a proto area + MS-wise db25 pinout. That should be discussed at some point.

So, it has all the basics to run an 8 cyl engine (are V8s wasted spark-able?), a dual rail 4 cyl, or a 6 cyl wasted spark engine. Plus, 3 analog GP inputs, plus 6 GPIO, plus 2 power outputs (use them however you want). The connector boards are meant to provide the flexibility, with different harness connectors, extra features (SD card logging, CAN, proto area, relays, etc). Probably, the first connector board will be as hackable as I can, and etched at home, since this is the only development platform I have.

About the license, I'll set it up later if there is no hurry.