Fred's first Puma board build

Marcos' unmaintained, but still in-use, Puma for FreeEMS circuit board/hardware design!
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Fred
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Re: Fred's first Puma board build

Post by Fred »

OK, so the cut cut join join serial mod works, BUT, requires a PNP transistor connected with collector to MCU rx (pin 1 on the ftdi), emitter to Puma 5v, base to USB connector 5v (pin 1, i think). There are three VERY convenient vias for this. There is a via next to C105 which is the USB 5v after the usb mods, there is a via next to the power pin on the stepper driver chip to get Puma 5v from, and on a 45degree angle from pin 1 of the ftdi there is a via for the mcu rx pin. I used a 2n5401 but probably any PNP will work.
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Re: Fred's first Puma board build

Post by Fred »

Last thing for the night, bed is calling:

When in SM mode, just touching the plastic case of the CPU gently can turn on all the ignition pins etc!! Thus, I propose that the design could incorporate pull downs on mission critical pins such that they stay in a known state when in boot load mode when the pins are all in high impedance states and very susceptible to interference.

I have a video to go with this, just before I realised what was causing it, IE, you can hear me say "wtf" :-)

Fred.
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Re: Fred's first Puma board build

Post by Fred »

OK, the mystery or the non-start is finally solved, it was the FTDI chip all along. I have removed my reset pin tant cap, and will at some point put a small ceramic on the pcb in parallel with those pins, but my board acts normally now due to bus powered usb AND transistor mod. Hooray, finally solved. Moving right along...
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Re: Fred's first Puma board build

Post by Fred »

Since then I've done a few things:

Switched pull ups on the rpm inputs for multiple input configs on the same board (traveling salesman ecu...)
Four VNP10N07 FETs with two bridged to PT6 and PT7 and the other two sharing two pins with two ignition channels.
Upgraded, but still not good enough, ignitor drive circuit consisting of 2n5401 transistors with 330ohm on the base, and 10 ohm on the output.
Bridged 12v input for simplicities sake and bench power use.
Added usb mini connector with bridge wires to the A connector

I'm about to post what I consider to be the summary of shit wrong/needs attention.

Fred.
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Re: Fred's first Puma board build

Post by Fred »

A lot of this is probably in posts above, but this is a fairly decent summary.
[15:37] <LibreEMS> the U18 chip can't be used due to no 12v source
[15:37] <LibreEMS> U31 is un-needed by me, and most, and I think the layout has issues.
[15:38] <LibreEMS> to220 locations for ign are unrequired, xor isn't really good enough to drive ignitors directly, and nor is my circuit, but its close enough for most, i'd like to upgrade mine further in that way
[15:39] <LibreEMS> i dont need or use p&h so all those chips are absent
[15:40] <LibreEMS> the weird stuff near regs is unrequired, leave out d3, r2, q18 and q9 and make sure you have a jumper on the underside
[15:40] <LibreEMS> many of the passives near U18 and U31 are related to them, and also not needed if you're not using those chips
[15:41] <LibreEMS> d26 and d24 should be removed
[15:41] <LibreEMS> r40 and r42 should be bridged
[15:42] <LibreEMS> r151 and r148 are tinned on mine (its in front of me now if you ahve questions) and IIRC i had to remove some parts from those.
[15:42] <LibreEMS>r212, r213, r215, and r216 should be 1/4w but thats tricky to fit. you could put them off board too
[15:43] <LibreEMS> for hall or opto use, you need a pull up on the inputs, and a floating ground input, NOT tied to ground
[15:43] <LibreEMS> for VR use, no pull ups and ground connected to VR
[15:43] <LibreEMS> you cant fit two winged map sensors on if you want aap, but there isnt code for it yet anyway
[17:07] <LibreEMS> also, the ftdi needs to be usb powered, not board powered, otherwise on a car the device comes and goes with the key, which with the ftdi driver on the mac is not good. additionally, you need a transistor in there to pull it up if the usb is unplugged and allow it to boot into the firmware.
Also see the file called "spin 2 modifications" in the master branch of nitrousnrg's puma repo on github (at the moment, at least).

Fred.
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Re: Fred's first Puma board build

Post by Fred »

Optional parts of the build:
[19:51] <LibreEMS> injector output drive is dependent upon injectors, input configuration setup is dependent upon rpm sensor type
[19:52] <LibreEMS> ignition polarity is dependent upon ign module type/design/style
[19:52] <LibreEMS> aap sensor is dependent upon altitude differential in the course of driving that persons car wherever they live
[19:53] <LibreEMS> no one should use the EGT circuit unless they are willing to hack and experiment
[19:53] <LibreEMS> the stepper drive is broken unless somehow fixed, and not needed by most anyway
[19:57] <LibreEMS> also, obviously, if only doing fuel, skip ign bits, and only ign skip fuel bits
[19:57] <LibreEMS> and, for now, routing wires to the fuel channels from PORTT pins, but that'll change with a software upgrade later.
There could be others.
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