Puma board for FreeEMS

[Fred]

The fuel pump pin is fine, if it's the same one as the document. I've started compiling data on the pin out issues and will post it up later.

Fred.

[nitrousnrg]

nitrousnrg, if Fred has a recommendation, would you be willing to add those pins? If Fred doesn't have a recommendation, can you add what ever fits and has a short trace? I see 5 perhaps 7 general purpose pins with the ability to be routed for general purpose use with out compromising the board layout.

Sure, lets see what Fred says. Those are very secondary pins, so we shouldn't loose much time deciding about those.

Oh also one RFI note we had made in the past, was to place an isolated non conductive ring around the perimeter of the board.

If you don't see it implemented in a week or two, please remind me.

CAELinux is good for thermal analysis/prediction

Whoa! I'll try to learn something about it.

Ah man, don't do that. If we need something, I can wipe it out.

Don't worry, I'd like to know that tool for other projects of mine.

The fuel pump pin is fine, if it's the same one as the document.

Ohh, thats important. I moved the fuel pump pin to PK0 since I knew Port A could have the weird behaviors. Ok, i'm falling back to the original setup.

MThis is my TODO, as far as I remember:

* load/run header switch
* change fuel pump pin
* extra pins routed to the 40-pin header
* pins with vias for testing
* silkscreen conditioning
* RF antenna around the pcb

[Fred]

Lemme check pk0 might be fine too. I don't care which pin it's on as long as it doesn't waste some other more special functionality. The fuel pump pin should be a boring pin. As for port A issues, they would matter on a coil, but not on a relay, even if the fuel pump came on for a second it's no big deal. I'll check pk0 and repost.

[Fred]

Probably best to not have it on PK0 actually.

[nitrousnrg]

Fuel pump is routed to the pin defined in the pin document (A7 or close).

I still have to route some other pins out to the signal connector, and correct some issues with the silkscreen. Grounds planes for power dissipation are done. This was a crazy week, I hope finish this soon and send it to the manufacturer in december.

[jharvey]

It appears that .6mm diameter SnAgCu filled via's can better the thermal PCB's thermal resistance by about 250% I posted more about the article I found it in at this link.

viewtopic.php?f=35&t=951

So to help with potential thermal issues, I might recommend peppering via's under the chips like the MCU, stepper drive, ect.

[nitrousnrg]

Cool, later I'll check what the manufacturer can do about it. It says I have to put bigger and fewer vias, and remove the solder mask area under the cpu and stepper driver.

I wonder if rust will be a problem in the non-masked area, since all the boards I etch at home get rusty in no time. Probably those regions are plated like a pad; in that case it won't be a major problem. Plus, it would have silicon grease, which also protects the copper from the atmosphere.

[nitrousnrg]

Damn, we don't have an input for the key.

Fred, consider adding it to pin-assignment.ods. The input should be in a interrupt-capable pin. Ports H and J can be used as an external interrupt source. Port P too, but it is the PWM-able one.

[nitrousnrg]

Nevermind, we agreed the key status was going to be monitored by reading the 12v with the MCU ADC. Let me have some testing so you can put it in the pin assignment ods.

[Fred]

If there is an ADC interrupt, then great, otherwise you're right, it needs to be added.

Fred.