[info] Frankenso - ECU shield compatible with OEM case / official

[AndreyB]

Manual:Hardware_Frankenso_board
pinout
SVN Repository
frankenso_schematic.pdf

frankenso_gerbers.zip
Bill Of Material
known_issues.txt

https://www.tinkercad.com/things/3xeOOU ... e-door-v03

x12 low-side VNS14NV04
x3 op-amp LMV324IDT
x3 high-side TC4427
x2 SD card socket
x1 VR INTERFACE MAX9926
x1 CAN interface SN65HVD230
x2 33uH Inductor
x2 CAP TANT 220UF
x1 IC REG BUCK 5V 3A
x1 CAP ALUM 680UF
x1 HIP9011 knock detection chip
x1 4MHz osc for HIP9011

case hole for micro USB: d=12mm, 7 mm from top, 46mm from right.

vertical space inside the case:
from top of red board to bottom of top cover - 23mm
from top of brain boardo bottom of top cover - 10mm

ibom available at https://rusefi.com/docs/ibom/

[AndreyB]

Based on Frankenstein board sales so far, at least 50% of the audience want a completely DIY platform.
An average Joe would not be able able to solder a 100 pin package - I am average enough and I've failed. Twice. http://rusefi.com/forum/viewtopic.php?f=4&t=381
Denso 64pin case is plentiful in junk yards, TE 64 pin connector is cheap and available.

I suggest we combine http://rusefi.com/forum/viewtopic.php?f=4&t=359 with http://rusefi.com/forum/viewtopic.php?f=4&t=552 and http://rusefi.com/forum/viewtopic.php?f=4&t=394 into a Frankenso board.

Frankenso = Frankenstein + Denso, not to be confused with case-less Frankenstein 10x10cm board.

[AndreyB]

I suggest we do not put any components under the discovery board - this way we would have an option to solder discovery right into Frankenso PCB, without a connector.

We have close to 4mm of vertical space on the back of the board inside this case, so I suggest we put most of the components on the back side of the PCB.

[Nobody]

Have you looked at aluminum extrusions from various manufacturers? It would be easy to design PCB once and be done with it.

[AndreyB]

Have you looked at aluminum extrusions from various manufacturers? It would be easy to design PCB once and be done with it.

There is a bunch of pictures attached to http://rusefi.com/forum/viewtopic.php?f=4&t=464
I have not yet seen anything of a regular ECU shape. On some cars you simple do not have space for 1.5-2 inches tall enclosures.

[Nobody]

Take a look at http://www.rose-bopla.com/Prod_Group_Pg ... _A_Box.htm many options, many heights.

I have a some left over profiles at home.

[AndreyB]

Take a look at http://www.rose-bopla.com/Prod_Group_Pg ... _A_Box.htm many options, many heights.

Alustyle 1230, something like ASP 1230-0150 is probably closest to stock ECU dimensions - still, I would want it to be a bit wider and a bit shorter. If we want to fit a LED screen inside (crazy idea, I know) we need something like 6x6x1 inch.

[kb1gtt]

There are a great many extruded alum case options. They are very low cost, but generally don't have mounting holes that fit a vehicle, so you would have to get into significant fabrication. Also you have to get the end plates machined which can cost far more than the enclosure. I've seen some nice looking, not square, not beige boxes that were made from this extruded alum processes. Also it's reasonably low cost to get a customer extrusion made.

The goal of re-purposing an ECU shell is to make it easier to work with.

[AndreyB]

Still need to synch knock sensing networks. Looks pretty scary already

[AndreyB]

The default pinout of this board would be based on Mazda Protege BG pinout

The beauty of this is that this same as Mazda Miata NA - see pafe 4 of 92diag.pdf

[AndreyB]

We would not need to drill the case wall if we use vertical mini-usb connector like TE 1734753-1 digikey A107790-ND mouser 571-1734753-1 $1.80

It would be super-cool if we would be able to make a universal module which would accept both regular miniUSB connector and vertical miniUSB connector. I guess I will ask @ to look into that.

Does anyone know a vertical microSD connector which would be available @ digikey or mouser?

[kb1gtt]

If we use a harness like this http://dynamic.focalprice.com/CA0548B/0 ... OgodlF4AgQ, you wouldn't need to open the ECU to get access to the USB. And you could mount the USB just about any where on any ECU.

usb_harness.PNG (64.54 KiB) Viewed 27857 times

I wonder if SD can be done on a harness connector like the above noted USB. That USB thing on PC's is very common.

Mouser seems to have vertical SD cards http://www.mouser.com/ProductDetail/Yam ... 2X3A%3d%3d however for that price, you might as well put a SD on a little PCB and then solder that in at a 90 degree. Something like this is nearly the same thing at nearly the same price. https://oceancontrols.com.au/MSD-005.html

Look in my "project_specific" KICAD library for "usb_u-mini-standard-header" Perhaps we can add the vertical USB to that footprint as well. I have not built this connector yet, but it should work for a variety of connectors. The only concern I've heard was about pick and place machinery. I choose only connectors that allowed for thru hole mounting as I feel that's a more rugged design. If something goes into qty production that would not be as friendly to low cost assembly as it could be. Other than that it should work fine.

Multi_USB.PNG (14.61 KiB) Viewed 27857 times

[AndreyB]

If we use a harness like this...

That's the wrong side of the USB - this this harness we would need to use a very unusual USB cable. But that's an option

[kb1gtt]

Ah, more like this you say http://www.datapro.net/products/usb-pan ... ocket.html

I'd think that lower cost and mini / micro can be obtained with more than a minute of shopping around. Seems panel mount is the hot word for that search.

[AndreyB]

Please join me in celebrating first Frankenso traces!

http://i.imgur.com/sBV9muT.png

[puff]

if it's not too late - please, make a provision for a bunch of simple level shifters (for 5V ignition modules like mine or logic-level controlled COPs) + for lm1815 vr inputs?

[AndreyB]

This board will be using MAX9926 and TC4427 same as Frankenstein, the question of component availability in Russia would need to be addressed separately

[puff]

the first one is not available from Russia's major electronic parts suppliers (although LM1815 is not available either), the second one costs an arm and a leg (in comparison to BSS138 - a handful for a coin). there's still some space on the board, and there are free legs on the microcontroller… what about egt and lambda controllers? knock sensor circuit?
i guess it would be somewhat a premature release…

[kb1gtt]

For outputs, there are 6 channels of high / low drivers. They can be wired to drive 12V or 5V, as well they can sink when they are not driving. Those are generally intended for driving an external ignitor. The AN inputs are also capable of translating a 12V digital signal into a 3.3V level signal.

Can you post a suggest circuit or something like that? If time permits I may find a way to include it, but I'm also very interested in drawing a line in the sand and getting this to a certain level of completeness. Also worth noting, this is a modular design. There have been several efforts made to allow additions and changes of modules.

[Number-One]

Very good.

[Sudo]

I haven't looked at the boards thoroughly, but the USB differential pairs need some work. And I don't recommend having 2 USB connectors in series. Those extra stubs can cause reflections. Another important thing for diff.pair is parallelism. Although you are not using High Speed, it is still a good idea to follow these guidelines:

http://www.usb.org/developers/docs/hs_usb_pdg_r1_0.pdf
http://www.electronic-products-design.c ... -impedance

[kb1gtt]

Good feed back, I'll read those PDF's. I understand the concerns about the stubs hanging out there like that for the secondary vertical mount USB connectors. I would expect only one to be populated at a time, so the cross talk and inductance/capacitance issues should be fairly small. However when dealing with MHz signals I can see how small variations can cause warp-age and potential issues. I don't know if the warp-age issues would cause the eye diagram to drop below the tolerance thresholds or not. I've seen some really dirty USB designs, so my gut feel is that it wold be tolerant of such issues. The reason for that funky USB is because we are looking for flexibility. I tend to like this approach for flexibility http://rusefi.com/forum/viewtopic.php?f ... s&start=11 Those harnesses can allow for the flexibility we are looking for, but they are kind of pricey and I don't like adding extra connections that can fail. So I'm not sure what is a better approach.

Keep up the feedback and feel free to tear it apart. What doesn't kill it will only make it stronger. All I ask is that you try to be content focused, and so far it's good content, keep it coming.

[kb1gtt]

The PDF suggest using 7.5:7.5 while I was using 8.5:8.5. KICAD claims the impedance for 7.5 is like this

7.5-7.5_trace-impeadance.PNG (64.5 KiB) Viewed 28090 times

while the 8.5 is like this

8.5-8.5_trace-impeadance.PNG (59.54 KiB) Viewed 28090 times

To me they seem close enough. I'm assuming the ZOe and ZOo are some how even and odd, and I have no idea why they don't match 90 ohms. Should I go that extra step for 7.5? I use 8.5 as it's 6 mill at a 45 degree angle. The PCB machines often do that 6 mill in the X and Y, which often makes your angles 8.5. By using the 8.5 you can often avoid headaches with failed angle traces. I think I'll leave that at the 8.5 as it appears to be only a 1 ohm difference.

[AndreyB]

From http://forum.chibios.org/phpbb/viewtopi ... 429#p16429

[Sudo]

I normally use Saturn PCB Design tool. http://www.saturnpcb.com/pcb_toolkit.htm What you are looking for is Zdiff. The Kicad tool doesn't show the result for that. Why is your "H" value so high? Assuming we will use OSH, It should be 6.7 mils according to their stackup. http://support.oshpark.com/support/arti ... tackup-and .

Both 8W:8S are within 10% tolerance according to the Saturn tool, more so than the 7.5W:7.5S. 9W:8S seems even better.

My concern wasn't the spacing or width, it was more so the parallelism and stubs. USB spec can tolerate some inconsistency in the routing, but I am just nick picking on it. At the end, if it works either way, it's all good to me.

[AndreyB]

Assuming we will use OSH

Probably not osh - osh would be ~$600 for three boards. Cannot afford this even for a test run

[Nobody]

Assuming we will use OSH

Probably not osh - osh would be ~$600 for three boards. Cannot afford this even for a test run

Try http://www.4pcb.com/66-each-pcbs/index. ... Mgod9jwAaw , I've been very satisfied thus far and yes really a US company and not farmed out to China. They even toss in a bag of pop corn - no joke LOL. I've even got an extra board before.

[kb1gtt]

Didn't know the OSH park stackup, thanks. That's much better. Following the USB guidelines much better, I checked in a better revised layout. I also added a pile of breakout vias such that you can solder wires to pins if you have the discovery board installed. Also many thanks about the link to pcb trace calculator.

About the screw, the screw I took out of the case is .165 major dia across the threads. and .265 inch across the head. I have put in a drawing that marks the PCB such that you know the screw head clearance. The hole in the PCB is very loose.

About the spacing of the chips in the top right, I expect there will be a piece of alum above it which will function as a heat sink. I expect them to each generate up to 5watts. I don't know or trust the datasheet's 27C/W thermal resistance, as I expect heat to flow via heat sink/case not just the PCB copper. Off of memory I seem to recall 10C/W to 15C/W, but won't really know until it's tested.

Time for some ZZZZ's. Keep up the good feedback.

[AndreyB]

Try http://www.4pcb.com/66-each-pcbs/index. ... Mgod9jwAaw

It would have been a great deal, but their $66 option is "Max. Size 30 sq. inches" and this board is 39 sq. inches

[kb1gtt]

Here's a picture that helps show the basic feature set found in this board.


I wanted to thank the folks who offered feedback. The feedback made the design that much better. To address the feedback that was provided by this forum thread, see below comments.
-- This design expects the use of the 90 degree USB connectors but has an optional standard USB connector. If the standard USB connector is used, there will be some "stubs", but they are less than the guides recommended max .2 inches long, so hopefully they would work good enough. As well parallelism is much better now. Attached prediction indicates very close to the suggested 90 ohm impedance.
-- Screw clearance checked and drawn on silk screen, as well a 100% scaled paper print out was done and checked in the enclosure. Several other clearance issues were avoided by this print out validation process.
-- Thermally I'm looking for an app note I once found that indicated if you put on a heat sink, you can get the Rth much lower. I'm working on creating a better answer, but that will take a bit. I expect we'll be OK thermally but we'll need / want a heat sink. The on-board thermocouples will allow us to measure the Rth as well we'll be able to use them for long term diagnostics and field thermal damage prevention.

Again thanks for the feedback, and please feel free to continue the feedback. I'm more than willing to add items to the TODO list or known issues list.