Search found 288 matches

by mck1117
Thu Jan 16, 2020 11:28 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

It's significantly more area and power required for not really any real performance benefit. The benefit it crank decoding and spark have virtually no lag and no meaningful distribution tail. Interrupts are the devil. But remember, if the timestamp is captured in hardware the interrupt can be prett...
by mck1117
Thu Jan 16, 2020 11:09 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

and/or angle clock. sure, you could do it completely angle based in an FPGA, but that makes it significantly more complicated to integrated in to the existing firmware, without really any added benefit. So long as the MCU can keep up with the interrupt rate from the FPGA (easy) and can schedule fut...
by mck1117
Thu Jan 16, 2020 7:44 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

If we had some kind of free-runnig multichannel timer that captures trigger events and generate output pulses using same counter - yes, this will be more precise. But stm does not have such advanced timers. May be it is possible by using timer synchronization. The stm32 can do a little bit of this,...
by mck1117
Tue Jan 14, 2020 1:10 am
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

but you'd still expect a normal distribution, at say 0.2 deg lag. The distribution is a function of the logic you're using and as I understand it all the time events in a single que. Not necessarily - the (improved) data show that the best possible event was 2.92us us late. That means that if every...
by mck1117
Tue Jan 14, 2020 12:48 am
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

What is this picture that note the isr45? I don't see x numbers or units for either axis. I'm not sure what it is trying to convey. It's a CPU usage visualization called a flame chart. Each horizontal row represents one process or thread (in our case, each row is one interrupt). Time progresses fro...
by mck1117
Mon Jan 13, 2020 8:29 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

Edit: it might also be worth repeating the you did at several rpm settings....you have 5k and below is probably only better but maybe 2500, 7500, 10000? if the error/lag is time based then the error should be linear with rpm and .2 deg at 5k should become 0.4deg at 10k which would be good to know b...
by mck1117
Mon Jan 13, 2020 8:19 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

A single mode shift of 0.2 deg is really not an issue, it will be adjusted for in the tuning. My only slight concern is it really looks like the 0,1us bucket is much bigger than it should be....suggesting a bi-modal distribution. I completely agree - the distribution absolutely is NOT normal, for g...
by mck1117
Sun Jan 12, 2020 7:53 pm
Forum: Misc
Topic: FPGA in ECU
Replies: 31
Views: 3689

Re: FPGA in ECU

Would we expect the Watts to go up, down or stay the same with the use of an fpga? I ask because some of the designs that are out there are very small. The Watts are important to consider for thermal regulation purposes on those small layouts. Could we some how include other features like a switchi...
by mck1117
Sun Jan 12, 2020 5:24 am
Forum: Hardware
Topic: TLE7209 or MC33186 H-Bridge Breakout
Replies: 17
Views: 824

Re: TLE7209 or MC33186 H-Bridge Breakout

I would recommend using a ceramic capacitor. That would be great, except that 50v 220uF ceramic capacitors don't exist. Essentially all OEM ECUs use electrolytic bulk caps for both the main supply and main relay "power device" supply (ETB, stepper idle, GDI boost supply, solenoids, etc). I typicall...
by mck1117
Sat Jan 11, 2020 10:29 pm
Forum: Hardware
Topic: TLE7209 or MC33186 H-Bridge Breakout
Replies: 17
Views: 824

Re: TLE7209 or MC33186 H-Bridge Breakout

So here's why the cap is required. Without a cap, the circuit forms an LC resonator (essentially a boost converter!) that can generate extremely high voltages at the tle7209's power supply. Here's a spice model, and corresponding simulation: https://imgur.com/wI7Kt7R.jpg Blue is the supply voltage, ...
by mck1117
Sat Jan 11, 2020 12:04 am
Forum: Misc
Topic: FPGA in ECU
Replies: 31
Views: 3689

Re: FPGA in ECU

but It also NEEDS an angle clock to be able to do that. So the fpga needs to be decoding the cranks and just sending rpm to the processor, which again could be read every 10msec so no issue with spi. But trying to send the tooth times seems a real stretch for spi and still requires the processor to...
by mck1117
Fri Jan 10, 2020 11:32 pm
Forum: Misc
Topic: FPGA in ECU
Replies: 31
Views: 3689

Re: FPGA in ECU

I would think you could measure time between crank pulses on an fpga, send this to mcu to calculate rpm, fuel/spark timing and pulse widths and send this information back to the fpga to control the outputs. This should easily be achievable using spi since the data sent back and forth is minimal. Th...
by mck1117
Fri Jan 10, 2020 11:12 pm
Forum: Misc
Topic: FPGA in ECU
Replies: 31
Views: 3689

Re: FPGA in ECU

It's easiest to not try to think of the FPGA running the whole engine. Try to think of the FPGA instead as a box in which you can build any magical timer peripheral that you could theoretically have inside the MCU. At the very least, you could move our scheduling priority queue to hardware. Over an ...
by mck1117
Fri Jan 10, 2020 10:01 pm
Forum: Misc
Topic: Is stm32f4 the right chip?
Replies: 135
Views: 16480

Re: Is stm32f4 the right chip?

My other question would be what happens to stuff ot on the due list like the fuel pulse and ignition timing as the number of time critical events goes up? As a general rule they should be done every 10msec or so......can you add something to track this to you project? If this is also good the you'r...
by mck1117
Fri Jan 10, 2020 7:55 pm
Forum: Misc
Topic: Is stm32f4 the right chip?
Replies: 135
Views: 16480

Re: Is stm32f4 the right chip?

FYI all, I've been investigating current scheduling performance on stm32 (and improving it by an order of magnitude): viewtopic.php?f=5&t=1657&p=35269
by mck1117
Fri Jan 10, 2020 6:36 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

Okay, now for the data after I implemented some improvements in these three pull requests: https://github.com/rusefi/rusefi/pull/1090 https://github.com/rusefi/rusefi/pull/1091 https://github.com/rusefi/rusefi/pull/1092 Here's the statistics from a capture under identical conditions to the previous ...
by mck1117
Fri Jan 10, 2020 6:35 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

Re: [info] rusEfi Scheduler Performance & Accuracy

Here's what the world looks like today. Both this test and the next were performed under identical conditions, only swapping out the code running on the mcu. The ECU was running a v8, sequential ignition and fueling, at 5000 rpm and 30 degrees of ignition advance. That equates to around 60-70 total ...
by mck1117
Fri Jan 10, 2020 6:34 pm
Forum: Software
Topic: [info] rusEfi Scheduler Performance & Accuracy
Replies: 34
Views: 484

[info] rusEfi Scheduler Performance & Accuracy

This thread was prompted by some questions asked in this thread: https://rusefi.com/forum/viewtopic.php?f=13&t=816&start=90 Background For nearly all outputs, rusEfi uses a single global scheduling queue. This includes injectors, ignition coils, and PWM (idle, ETB, etc). When we decide that we know ...
by mck1117
Thu Jan 09, 2020 7:04 pm
Forum: Misc
Topic: Is stm32f4 the right chip?
Replies: 135
Views: 16480

Re: Is stm32f4 the right chip?

mck1117 wrote:
Thu Jan 09, 2020 7:02 pm
If we're going to go after "ultra scheduling precision",
By the way, this comment is not a recommendation that we do something different. There are still significant improvements to be made within the existing "fully software scheduled" world.
by mck1117
Thu Jan 09, 2020 7:02 pm
Forum: Misc
Topic: Is stm32f4 the right chip?
Replies: 135
Views: 16480

Re: Is stm32f4 the right chip?

Isn't this thread about changing hardware architectures from STM32F4 in order to get a more accurate timing response? I have a PR out that improves ignition timing precision by an order of magnitude. More on that later. Granted hardware and software design complexity would increase. But that would ...
by mck1117
Thu Jan 09, 2020 2:08 am
Forum: Hardware
Topic: let's choose an enclosure
Replies: 106
Views: 14738

Re: let's choose an enclosure

russian wrote:
Tue Jan 07, 2020 6:09 am
mck1117 wrote:
Mon Jan 06, 2020 11:11 pm
The other consideration with those connectors is that you have to solder the connector once it's installed in the case - so you can't remove the board or access the top side if it's installed in a case.
Hold on, this is quite unacceptable for us DIY is not it?
Depends on how brave we are!
by mck1117
Thu Jan 09, 2020 1:57 am
Forum: Misc
Topic: Is stm32f4 the right chip?
Replies: 135
Views: 16480

Re: Is stm32f4 the right chip?

The first place I worked as a young engineer the QA manager has a sign over his desk that read "In God we trust, all other bring data". Do you have data this? Does it change with RPM or as the the number of cylinders increases? I've wanted to measure this in a scientific way for a long time. I made...
by mck1117
Wed Jan 08, 2020 10:12 pm
Forum: Misc
Topic: Is stm32f4 the right chip?
Replies: 135
Views: 16480

Re: Is stm32f4 the right chip?

I agree, this seems like a solution in search of a problem. At 6000 RPM, 1 degree is 46 microseconds. We're better than 15us jitter and absolute accuracy, so we can certainly do better than 1/3 of a degree under all real conditions. There are software improvements I know of in this domain that we co...
by mck1117
Mon Jan 06, 2020 11:11 pm
Forum: Hardware
Topic: let's choose an enclosure
Replies: 106
Views: 14738

Re: let's choose an enclosure

Those connectors are pretty common. GM gen4 (2005+) v8 engines use those connectors, I think.

The other consideration with those connectors is that you have to solder the connector once it's installed in the case - so you can't remove the board or access the top side if it's installed in a case.
by mck1117
Sun Dec 29, 2019 2:33 pm
Forum: Hardware
Topic: EFI for small engines
Replies: 45
Views: 2415

Re: EFI for small engines

The last digit of the part number indicates the temperature scale. For example, the STM32F407VGT6 that comes on the F4 discovery board is rated for -40 to +85C. The STM32F407VGT 7 is identical but rated -40 to 105C. Most of them only come in the 6/7 flavors, but a few (as you've discovered) come in ...
by mck1117
Sun Dec 29, 2019 2:27 pm
Forum: Your car & your engine
Topic: 2006 Volkswagen Passat 2.0 Turbo GDI test mule
Replies: 10
Views: 881

Re: 2006 Volkswagen Passat 2.0 Turbo GDI test mule

Random bosch injector datasheet https://raw.githubusercontent.com/wiki/rusefi/rusefi_documentation/oem_docs/Bosch/Data%20sheet_67828491_HP_Injection_Valve_HDEV_5.2.pdf Maybe we need more or less similar 65-90v @ 13.2A for 500us followed by 12v@~3A for the rest of the pulse? Maybe pin 1 is also posi...
by mck1117
Sun Dec 29, 2019 2:16 pm
Forum: Your car & your engine
Topic: 2006 Volkswagen Passat 2.0 Turbo GDI test mule
Replies: 10
Views: 881

Re: 2006 Volkswagen Passat 2.0 Turbo GDI test mule

With 50 PSI pressure you can open and close with just 12v. You need the boost voltage when you have high pressure. Do you have a plan for generating high pressure? You don't need the high voltage to open the injector, just to open it quickly. With DI you're in a bit of a rush to get your injection ...
by mck1117
Sat Dec 21, 2019 3:31 am
Forum: Hardware
Topic: rusEfi own wide band controller board add-on using CJ125
Replies: 325
Views: 30541

Re: rusEfi own wide band controller board add-on using CJ125

The shape of the temperature curve doesn't actually matter. You're just trying to keep the resistance (and as a result temperature) at some constant point, so you don't really care the shape of the curve as you shouldn't ever be deviating very far. Since the function of resistance (and as a result v...
by mck1117
Sat Dec 21, 2019 3:27 am
Forum: Hardware
Topic: Schematic and PCB review - custom rusEfi board
Replies: 22
Views: 1547

Re: Schematic and PCB review - custom rusEfi board

Dron_Gus wrote:
Wed Dec 18, 2019 6:49 am
Discrete output FETs are not. :)
Hey, they're not discrete, they're paired overtemp/overcurrent/active clamp drivers!
Dron_Gus wrote:
Wed Dec 18, 2019 6:49 am
I hate wiring, so I definitely need p'n'p HW.
Ok well yeah in that case, you shouldn't run a Proteus :P
by mck1117
Thu Dec 19, 2019 2:26 am
Forum: Hardware
Topic: microRusEfi
Replies: 218
Views: 18054

Re: microRusEfi

total of only 0.8 watt. isn't that per cyl? I think adding Rds will put you closer to 1w. Shouldn't that be more like 4x. So 4 injectors world be 4w? Also didn't we do a calc for mre which was closer to 1.8w per injector? If course measurement's remove allot of the theory. No. That math was for 200...