How does FreeEMS currently implement the standby mode?

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slacker.cam
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How does FreeEMS currently implement the standby mode?

Post by slacker.cam »

Looking through the schematics for the PUMA board I see no input to the uC to trigger the unit into standby when the ignition key (and hence the switched 5V supply) is removed. How is this currently implemented? I have a funny feeling that it's not implemented at all just yet and the uC is constantly powered up but I may be wrong? The couple of searches that I did provided no clues. When building my own hardware should I be making some type of provision for this or shall I just ignore it for now?
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Fred
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Re: How does FreeEMS currently implement the standby mode?

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slacker.cam wrote:I have a funny feeling that it's not implemented at all just yet
Your funny feeling is correct.
and the uC is constantly powered up
This is the default, while the key is on, for now.
When building my own hardware should I be making some type of provision for this or shall I just ignore it for now?
That is up to you. I'd like to support "on with key only" operation, as well as the always on mode. I currently don't know what is and isn't possible. If you add stuff for this, it will be straight forward to bridge them and have on with key as default (the machine always needs to work correctly from a cold boot, after all...). I'd say probably ignore it for now, as you don't need it, and it's extra complexity (components and traces...) on the board. KISS.

PS, GREAT to see you having some involvement. I look forward to your youtube clips showing up in the near future :-)

Fred.
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slacker.cam
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Re: How does FreeEMS currently implement the standby mode?

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Yep, sweet. I figured as much. So the two 12V lines into your Puma board are both connected to the switched ignition source? Ie. the board is completely dead while the key is off?

I shall follow suit.
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Re: How does FreeEMS currently implement the standby mode?

Post by Fred »

On the Puma, Marcos got lucky, by lack of fundamental concept understanding, and connected the battery voltage reference input to the "dirty" power line, which he wrongly intended to power injectors and coils THROUGH the board. As such, it became a dedicated batt voltage feed line, which is ideal, as Puma has no dirty power requirements anyway and an untainted voltage feed to battery ref input is strongly recommended.

Yes, dead while key off.

Follow suit :-)

Fred.
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jharvey
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Re: How does FreeEMS currently implement the standby mode?

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I think you already mentioned this, but I can't recall. Is yours a TA card with a bread board/proto board? Marco's plan was to have a kill switch, that's what those transistors where about. His quick stab attempt failed, and I seem to recall it will be replaced with other components.That options is available on many regulator supply chips.

I understand Fred's long term plan is to have an always on connection to the ECU, and switch off injectors, such loads when the key is off. I believe this always on approach would help with the boot time, and with the long term plan to be always on, I'm not sure what the typical boot time is for the firmware as it stands now. I believe it's under 100mS, which isn't really that bad, but isn't as good as we would want. So one potential obstacle to keep in mind is to wait a fraction of a second before cranking.

Lets see, what other circuits had multiple options that could potentially bugger your draft.

Oh, Diodes like D99 the 5V1 didn't work out. They conducted when the datasheet claimed they shouldn't. For now I'd recommend leave it out. Some day I need to test the leakage current on a hand full of samples I have around here. So some day we may have a suitable replacement, but for now we don't know what one would be good.

U18 the thermo couple was buggered. Don't use it. Or look at it closely before you try to use it. I believe there currently isn't any software behind it either.

U31 the stepper may or may not work. It hasn't been tested yet.

U20 the FTDI USB chip has a transistor. I don't fully know what this does, but if you have a TA card you may need to do something with that transistor. I believe you can ignore it.
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Re: How does FreeEMS currently implement the standby mode?

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jharvey wrote:I understand Fred's long term plan is to have an always on connection to the ECU, and switch off injectors, such loads when the key is off. I believe this always on approach would help with the boot time, and with the long term plan to be always on, I'm not sure what the typical boot time is for the firmware as it stands now. I believe it's under 100mS, which isn't really that bad, but isn't as good as we would want. So one potential obstacle to keep in mind is to wait a fraction of a second before cranking.
Boot time is virtually instantaneous, that isn't a problem. The power of being always on, is knowing when you were last on, and controlling what you can store at close down, without having to store to non volatile constantly. This gives you the ability to do things that without being always on, are not possible, at all.
U18 the thermo couple was buggered. Don't use it. Or look at it closely before you try to use it. I believe there currently isn't any software behind it either.
Marcos fed it 5v instead of 12v, so its only good to a low temp, lower than the ex stream. you could set it up with a 12v reg and tolerate it not functioning during cranking or other low V conditions, i think that is acceptable, as it's only useful while cruising, or beating the snot out of it, in which case the alternator or generator is working well.
U20 the FTDI USB chip has a transistor. I don't fully know what this does, but if you have a TA card you may need to do something with that transistor
Typo? "may not" not "may" ? You don't need to think about this at all.

Fred.
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slacker.cam
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Re: How does FreeEMS currently implement the standby mode?

Post by slacker.cam »

I think you already mentioned this, but I can't recall. Is yours a TA card with a bread board/proto board? Marco's plan was to have a kill switch, that's what those transistors where about. His quick stab attempt failed, and I seem to recall it will be replaced with other components.That options is available on many regulator supply chips.

Yep, I have a TA card with a veroboard 'wing' for each of the IDC connectors which are connected via a short ribbon cable. I'll use this system for now as I only plan on running the engine on a stand. I may build my own PCB at some stage but it'll be easier to jump in on spin2 (if thats even allowed) and save myself the hassle. Sorry, which transistors are you referring to?
Oh, Diodes like D99 the 5V1 didn't work out. They conducted when the datasheet claimed they shouldn't. For now I'd recommend leave it out. Some day I need to test the leakage current on a hand full of samples I have around here. So some day we may have a suitable replacement, but for now we don't know what one would be good.
For digital lines a 5V1 zener should be fine so long as the series resistance isn't so great that the voltage is shunted to a level that's too low to toggle the IO pin. Actually, unless it was an extremely poor zener who's knee was far below its rated voltage. My preferred method is to use a 5V1 zener for digital stuff and use two small signal diodes on the analog stuff (similar to what Marcos did on the Puma board).
U18 the thermo couple was buggered. Don't use it. Or look at it closely before you try to use it. I believe there currently isn't any software behind it either.
No thermo couple needed for my basic setup. Thanks for the heads up though.
U31 the stepper may or may not work. It hasn't been tested yet.
No need for stepper drive on my setup either. I have a 3 wire Toyota PWM idle valve so all I'll need is a couple of transistors when someone eventually writes some PWM idle code.
U20 the FTDI USB chip has a transistor. I don't fully know what this does, but if you have a TA card you may need to do something with that transistor. I believe you can ignore it.
No FTDI for me. I'll stick with the RS232 line driver that's on the TA card. Pretty sure I don't need that transistor, although I don't know what it does exactly.
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Re: How does FreeEMS currently implement the standby mode?

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slacker.cam wrote:I may build my own PCB at some stage but it'll be easier to jump in on spin2 (if thats even allowed) and save myself the hassle.
Once tagged, they can't stop you printing one, but he said he's not going to allow others to be part of the next group buy unless he thinks they are up for it, or something like that.
slacker.cam wrote:Sorry, which transistors are you referring to?
An experiment-gone-wrong for always on power control.
slacker.cam wrote:No FTDI for me. I'll stick with the RS232 line driver that's on the TA card. Pretty sure I don't need that transistor, although I don't know what it does exactly.
You don't need it, as I slightly unclearly said in my last post.

Fred.
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jharvey
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Re: How does FreeEMS currently implement the standby mode?

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slacker.cam wrote:Sorry, which transistors are you referring to?
The spin one branch had some power supply transistors that aren't there any more. Sorry ran out of time. I'll try to remember to reply later.
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Re: How does FreeEMS currently implement the standby mode?

Post by Fred »

jharvey wrote:
slacker.cam wrote:Sorry, which transistors are you referring to?
The spin one branch had some power supply transistors that aren't there any more. Sorry ran out of time. I'll try to remember to reply later.
They were intended to switch power between regulator and devices or some such thing. They were also intended to be FETs not BJTs. In either case, you're doing key switched power only, so you don't care.
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