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Fred's first Puma board build 
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This thread is to document my first Puma build! I'll be making and recording some changes and observing things and making notes on what to put in Spin 2, etc, here. This thread is for me and Marcos only, Marcos, use the other thread for general stuff, but for tech, put it here.

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viewtopic.php?f=9&t=1037

Fred.

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Wed Feb 09, 2011 11:28 pm
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Initial observations:

MAP and AAP can not be mounted together as they are too wide. one or both would need one mounting hole cut off to use them like this. There is room for AAP to migrate closer to the corner and fit OK just by stretching the traces routed around it. These would have been better in SMD packages as then no mounting would have been required. As it stands they will need to be screwed to the end plate of the enclosure.

There are some tiny balls of solder stuck to the board in random places, if these came free they could short out pins. They are stuck on with flux so when washing the board post assembly they should come off easily.

It looks to me as though the pull up on the FTDI chip can attach to either of the resistors at the connector end because they are joined by a trace anyway. This resistor should probably be soldered across both of them for physical strength and hot glued in place to avoid vibration failure. An 1/8 package would be better than a 1/4 package for weight/vibration reasons, too.

As we already know, USB A doesn't belong here, however USB B is also out of place because both A and B are HUGE. I would strongly suggest moving to mini USB for the Puma design as it is more common (IMO) and more compact allowing more PCB real estate for other things.

The to220 packages on one side are closer to the edge than on the other, this should be consistent.

Two of the leads on one of my max chips are damaged from rework, but I think it will still work after looking at a bare board for trace routing/pad connections.

I don't understand what the fuel pump + and - pins are for! The fuel pump output should just be a ground when enabled which will switch a relay or actually power a small pump if the FET is good enough and the ground source seperated on the PCB. What are these two connections for? What about the three passives next to the FET, what are they for, why empty?

What does DGP stand for? And AGP? What is the GP NTC pin for?

What is the link between D3 and Q19 for? What are Q18,Q19,D3,D4,R2,C11,C8,C2 for?

I love the SMD crystal, it looks very nice.

The mounting points in the corners appear to be connected with the ground plane, this is a terrible idea/bad/wrong. NO, wait, they're not, it's just really hard to see on the top side with the white circles around them, is that white circle necessary, there is no component to line up with the outline, perhaps it'd be better left off, I don't care though, as long as the holes are not connected. The should remain plated for robustness, though.

I can't see specific ground connections, are there any or is it the connector boards responsibility to merge appropriate groups into external connections? Where should I ground it for bench testing?

What are K+ and K- for?

What are the four unlabled pins in the DIL header for? It looks like they are NC (not connected)? If so, and it was in order to use a standard 40 pin header, then OK. BUT, it wont fit in due to the reference pin having a significantly smaller hole!

Do your INJ1-8 numbers line up with the CPU numbering of outputs 0 - 7 on port B being fuel outputs 1 - 8? If not, renumber them to be out of order on the PCB and match the CPU. The connector board and connector should probably have them in a sequence, but actual placement does not need to be. Ignore this comment if it's correct already.

What are the two missing diodes on each ignition channel for? What about the 3 resistors and 1 capacitor on each GP FET?

How do you configure the XOR chip and how is it configured stock? This is for the four ignition channels, right? What are the two missing resistors with the white box around them next to it for?

What about the two resistors and two diodes between the fuse holders and FTDI chip?

The fuse holders should be scrapped for spin 2.

What exactly does MCU fuse holder connect to? And the PWR one? I see the traces to the header holes.

I assume the 11 missing components around the missing U31 stepper driver chip are related to it?

U18 is the thermocouple driver, right? And some of the missing nearby components are for that, right? What about the rest? I know there are two resistors missing from the VR inputs, but there are a lot of passives missing in that region.

What are D101 and D102 for? Also missing.

There is a single missing component next to the map sensor with an unreadable mask, what is that for?

I need you to explain in detail how the power supplies are split and what you were saying about them the other day. I don't know what you've done, or how it works, and therefore can't whinge about it, or pat you on the back, or whatever is necessary. Help! :-)

The board quality looks really nice :-)

The dude who put the solder paste on needs more practice, perhaps a video of him doing it would show us how hard it is to do so we don't give him too much of a hard time about it ;-)

I need to investigate fet usage and ignition driving pull up/downs, and VR input pullup/downs and VR input resistors and think about/respond to your responses to the above questions/comments. Most of it should be easily answered, some of it is old news, but I need to have a full understanding of this thing before I try to use it.

I can't wait to try it out on the bench, and even more so, the car, later :-)

I can't think of or see anything else for now!

Fred.

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Thu Feb 10, 2011 4:04 am
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Also, re part ID, I think it's pretty important to be able to read and link all labels to a component without ambiguity, but ONLY for DIY use, which isn't your goal, so... give it what it needs, but it'd be nice if that one part was fixed next to the map, somehow.

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Thu Feb 10, 2011 4:10 am
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Quote:
MAP and AAP can not be mounted together as they are too wide
Probably true. I'm adding all this things to the "spin2 improvements" file.
Quote:
There are some tiny balls of solder stuck to the board in random places
I think i can't help it without a stencil for applying the paste. Spin2 will come with a stencil from ourpcb (in case I assemble them).
Quote:
soldered across both of them for physical strength and hot glued in place to avoid vibration failure
Wussy
Quote:
I would strongly suggest moving to mini USB
Yes, mini is on the way.
Quote:
The to220 packages on one side are closer to the edge than on the other, this should be consistent.
True. added.
Quote:
Two of the leads on one of my max chips are damaged from rework
. It was a memorable fight. Lucky I didn't had the hammer around.
Quote:
I don't understand what the fuel pump + and - pins are for!
(-) is just ground. the other is what you want. probably unnecessary. However, the board needs more ground pins.
Quote:
What about the three passives next to the FET, what are they for, why empty?
Probably is a snubber circuit. You don't need it.
Quote:
What does DGP stand for? And AGP? What is the GP NTC pin for?
Those must be renamed. Figured that out when I saw the boards the 1st time. Digital General Purpose, Analog General Purpose, General Purpose NTC resistor input. It should be directly PH1, PJ3, AN12, etc. NTC or not should be selectable by bridging something.
Quote:
What is the link between D3 and Q19 for? What are Q18,Q19,D3,D4,R2,C11,C8,C2 for?
You might wanna put D3, its a reverse protection diode. Q18-Q19 cuts the 12v supply for the big regulator, although one of them is too small.
R2= 1ohm resistor in series. The bridge you have bridges all that stuff.
D3 is connected between 12v and 5v. Its function has a name but i cant remember it.
The capacitors are for 12v and 5 supplies. 2200uF and 10uf.
Quote:
I can't see specific ground connections, are there any or is it the connector boards responsibility to merge appropriate groups into external connections? Where should I ground it for bench testing?
Ground comes from the other board, I'd like to see more ground pins, though. Mine gets power from P5 and P3 (the unstandard header next to the fuses)
Quote:
What are K+ and K- for?
Thermocouple
Quote:
What are the four unlabled pins in the DIL header for?
Yes, they're NC. I don't understand how it ended with a different hole. Its corrected for Spin2, but i don't see how could that happen. Btw, the header fit if you push it hard enough ;-)
Quote:
Do your INJ1-8 numbers line up with the CPU numbering
Yes, inj 1 = PB0, and so on. Not sure if its port B, but its the port used for injectors.
Quote:
What are the two missing diodes on each ignition channel for? What about the 3 resistors and 1 capacitor on each GP FET?
Clamping and zener (ran out of 5.1v zeners). For GP: R-C Snubber and... umm the other is either the LED resistor or a 100k pulldown. I doubt its the unavoidable 1k resistor. Probably a mistake.
Quote:
How do you configure the XOR chip and how is it configured stock?
Not configured yet. Populating one of the 2 resistors placed into the white box, you are pulling down/up one of the XOR inputs
Quote:
What about the two resistors and two diodes between the fuse holders and FTDI chip?
LEDs. Mines doesn't flash :-(
Quote:
What exactly does MCU fuse holder connect to?
To the upper board that provides the connector :-)
Quote:
I assume the 11 missing components around the missing U31 stepper driver chip are related to it?
You're right.
Quote:
What are D101 and D102 for? Also missing.
5.1v zeners.
Quote:
U18 is the thermocouple driver, right? And some of the missing nearby components are for that, right? What about the rest? I know there are two resistors missing from the VR inputs, but there are a lot of passives missing in that region.
Yes, its for the thermocouple, and yes they are for that chip.
About the rest:They are all missing capacitors, used for filtering. You have 0805 caps there, practice some soldering;-). For example, MAP is already filetered, BRV too. check the schematic for that. It will work without the caps, you may see some avoidable noise, though.
Quote:
There is a single missing component next to the map sensor with an unreadable mask, what is that for?
Its only a pullup for diagnosis (MAP signal goes to 5v in case of a brak cable), but it doesn't pull anything. It was a schematic error (from me)
Quote:
perhaps a video of him doing it would show us how hard it is to do
It'd be a long,boring video.

Quote:
I can't wait to try it out on the bench, and even more so, the car, later :-)
Come on! what are you waiting for?? :-)

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Thu Feb 10, 2011 6:23 am
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nitrousnrg wrote:
Come on! what are you waiting for?? :-)

USB cables/fittings :-p ;-)

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Thu Feb 10, 2011 6:52 am
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OK, I have found a few more things:

The pin connections for darlingtons are wrong for P&H use, nitrous can provide a fix.

The pins for the darlingtons can be used for autofets as they all go a very short distance and thus can just be jumpered around as required.

The thermistor circuits have 3 resistors, R148 and equivalents should NOT be installed, or thermistor readings WILL be wrong and tables can not be generated.

2.2k resistors are used for the thermistor bias resistors, this is a good choice, so would 2.4 be, they SHOULD be fine tolerance, I *think* 222 means that its 5% and 2201 would bean 1%? So these are wrong on my board, however i'll tolerate the wrongness for the time being. Spin 2 will have this shit sorted out and those yet to build can get it right anyway. If you're building for a specific set of thermistors you should use the most appropriate resistor to centre your accuracy where you want it, usually mid curve. Download FreeTherm and run it, you can probably use the resulting file pretty easily with a copy paste into open offce to view the curve.

desoldering smd is difficult without being destructive.
soldering smd is difficult without 3 hands or some stuff to hold parts still or glue. I used "super glue" / cyanoacrylate to stick mine down before soldering them.
the key to nice joints is speed, apply heat, apply solder, remove iron
wiping pads clean with wick is difficult with other parts surrounding them - do as much assembly as you can in one go and with an oven.
hot air tools would make this a LOT easier to do
use quality solder

the pdf schematic on http://puma.freeems.org is out of date and shows 2.61k values for bias resistors
it also shows pip3104 which is what i have, but not in the BOM

on the four assembled boards I received, next to the FTDI chip, two smd resistor places are either both filled (2) or one filled (r185 filled)

the 8 fuel channels are ddriven by B0 - B7 which is good.

I've fixed up my CHT, but not IAT, yet.
I've not checked or modified BRV which needs to have it's own sense feed wired in somehow.

time for lunch, then more work.

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Mon Feb 14, 2011 3:11 am
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IAT has had r151 removed now.

Added 3 10uF 35V tants in C2, C8 and C11. Which didn't help with the startup thing. I'm now going to put another tant the same across reset and gnd just as marcos has done.

It's away laughing now, and both regs are staying cold with no heatsink! :-p

Need to:

  • review above long post by marcos and clarify/respond/thank for various things.
  • sort out battery measurement circuit and feed for it
  • map sensor and associated parts
  • bridge wires to FETs for fuel
  • install some sort of predriver for ign to drive my ignitors
  • check the tps circuit
  • adapt the led circuits to work with the modified outputs
  • wire a harness to it
  • attach some lumps of alloy to the to220 stuff
  • and write code

Will try to get more done tonight too... at least the first and last ones. probably some of the others too, not the harness or heatsink, yet, though.

Fred!

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Mon Feb 14, 2011 8:09 am
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Added 4 1/4 watt 10k resistors on inputs to max chips, not a reliable long term solution, but should do fine for now.
MAP sensor installed and tested without checking circuit, works fine.
Don't care about TPS for now, may do if i get time
Code written, need more, though.
Thought about what to do a lot...

Need to:

review above long post by marcos and clarify/respond/thank for various things.

First

  • sort out battery measurement circuit and feed for it
  • solder two caps on thermistor circuit C73 and C74
  • sort out pullups for CAS and polarity on the max chips vs the software
  • bridge wires to FETs for fuel from port T, two fets, one port T
  • configure and bridge wires from the XOR chip to drive my ignitors - need to check whether 5v or 0v is dwell on car first.
  • adapt the led circuits to work with the modified outputs

Last:

  • wire a harness to it
  • attach some lumps of alloy to the to220 stuff

Fred.

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Tue Feb 15, 2011 5:07 pm
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battery measurement done, works, pretty accurate on steady state power supply
c73/c74 done
pullups on cas inputs done - need to check input signal polarity vs code
two port t pins driving two fets done - but they appear on, so may need to invert them somehow...
alloy enclosure made/sort of

still need to look at XOR chip stuff and current off state voltage
still need to wire it up

still need to read marcos' post again

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Wed Feb 16, 2011 3:50 am
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got the XOR stuff sorted, and started wiring it up, and read marcos' post again, and then ran out of time. I'll probably try to finish wiring it up today... will let you all know how i go and post pics at some point soon so others can emulate if they want to.

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Thu Feb 17, 2011 12:15 am
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