True programable ecu ?

[Enchanter]

Why is it that there seems to be no truely programable ecus out there.
By programable I mean like a basic pc, not a win box, more like an early computer like the c64, atari st or amiga.
A system like this wouldn't need much of an operating system so it should be stable. Anyone that can do simple programing and has a good knowledge of the way an engine works could do up a system that runs a car, and you could have it do whatever you wanted it to do until you run out of outputs.
"Cant run VVTi ? well I better rewrite the software !" Why isnt it that simple?
I mean what is so hard about recieving various peices of data from the sensors, chucking in some simple logic statements and out putting more data ( firing injectors, adjusting timig etc ).
Am I missing something here or do todays ecus have some magic circitry that the car must have to run yet stops it being truely flexible?

[thechuckster]

The CPU from a C64 or Amiga (motorolla chips) are just that - a CPU - no memory, no BIOS, no memory controller, no A/D inputs & outputs, no clock,etc.

If you want programable that you can write your own code for try Megasquirt. It uses a ECU designed for this kind of use (has onboard clock, ram, flash ram, bios, i/o control, et.

The magic isn't the ability to drive lots of output and use various sensors - it's the code that glues them all together. Rather than describe it, have a long read thru the General Informtion section of the msefi forum.

[Bahnugget]

chuckster's right, C64 would bite some big ol' wang, its really simple, and fun re-writing magnetic sequences on tapes isnt it!! yay for binary! i can see a windows box with the right amount of tampering POSSIBLY becoming a suitable ecu, but the fact is there are far simpler options out there that work just as well

[oldcorollas]

yup, MS is one of the few systems (as well as the atmel based breakaway.. ) where you can,and are encouraged to, write your own code.

the main issue with using a PC based kind of system is that that ae not exactly real time.

a car controlling ECU needs to have a VERY good idea of what is happening when, so that injection, and MUCH more importantly, IGNITION, occur at the correct time. 8000rpm is about... 8ms per 360deg, so you'd want to have better than ms resoltion RELIABLY...

you can even download the open source Megasquirt code, which for MS1 is in motorola language (can't remember proper term for it ) but for MS2 is in C.

you can easily just alter the code and try it yourself.

the guys that designed these systems are very cluey (ie motorola engineer, coding expert etc) but there is nothing to say you can't do it yourself

but i will say there is more to the implementation than first appears

you can probably look back at the DIY-EFI list and get some ideas, but from that grew the MS, and it is probably the most widely used and easy to adapt out of homegrown ECU's..

it'll be fun

[oldcorollas]

oh, and MS1's chip is 8MHz.
MS2 is??? 16? 25MHz? plenty of power to play with.

[Enchanter]

The CPU from a C64 or Amiga (motorolla chips) are just that - a CPU - no memory, no BIOS, no memory controller, no A/D inputs & outputs, no clock,etc.

I realise there is more to it than the cpu by its self, but really is there anything stopping someone from pluging in a computer to run an engine (apart from boot up time and lack of software)?

If you want programable that you can write your own code for try Megasquirt. It uses a ECU designed for this kind of use (has onboard clock, ram, flash ram, bios, i/o control, et.

I hadn't thought about programing the megasquirt myself, I will def look into this.

The magic isn't the ability to drive lots of output and use various sensors - it's the code that glues them all together.

Exactly my point, why are they all so inflexible?

[Enchanter]

yup, MS is one of the few systems (as well as the atmel based breakaway.. ) where you can,and are encouraged to, write your own code.

you can even download the open source Megasquirt code, which for MS1 is in motorola language (can't remember proper term for it ) but for MS2 is in C.

you can easily just alter the code and try it yourself.

Cool, I know a little C.

[nihilism]

shhhh... don't tell everyone my ideas!

[thechuckster]

I realise there is more to it than the cpu by its self, but really is there anything stopping someone from pluging in a computer to run an engine (apart from boot up time and lack of software)?

reboot requires reloading of OS and software for any reset, having onboard in flash ram and a hard-coded OS means near instant restart.

Then there's the reliablility of code along with a reliable OS (the BMW's that use MS for car management gets BSOD rendering anything electrical in the car dead.

Then there's the rugedness of the hardware - how tempremental would a 10-15 year old C64 be for varibale power, heat, vibration etc...

I hadn't thought about programing the magasquirt myself, I will def look into this.

very worth your while - heaps of success stories nowawadays and in the state's there's lot of modern cars getting this to provide cheap programable engine management.

Exactly my point, why are they all so inflexible?

proprietary software - they make money out of the IP vested in their code, take that away and all they do is sell cheap boxes of silicon.

[Enchanter]

a car controlling ECU needs to have a VERY good idea of what is happening when, so that injection, and MUCH more importantly, IGNITION, occur at the correct time. 8000rpm is about... 8ms per 360deg, so you'd want to have better than ms resoltion RELIABLY...

Hmm, could this be why the megasquirt has only been programed for use with a distributor ?

[oldcorollas]

I realise there is more to it than the cpu by its self, but really is there anything stopping someone from pluging in a computer to run an engine (apart from boot up time and lack of software)?

yes. the time based interrupts needed for timing within the engine.

sure a PC has power to burn, but it isn't realtime based... because it doesn't need to be...

i had the same thoughts, but luckily before i went too far down the track, the MS project was announced out of the DIY-EFI ashes

[oldcorollas]

Hmm, could this be why the megasquirt has only been programed for use with a distributor ?

nope. MS can do other things too you need to look at MS2 and MSnS, and MSnEDIS..
i like the EDIS idea, btu they are hard to come by in Aus, although you can always get one sent from US or UK..

you might want to se if you can be involved in the UMS project also.. that will be the uber puta. fully programmable outputs. CANBUS cascadable (sp ) etc etc...

[thechuckster]

Hmm, could this be why the megasquirt has only been programed for use with a distributor ?

no - it can run off crank triggers, dizzi triggers (like you find in toyotas), cam triggers, optical trigges (on cams, cranks and dizzis) .. most of it depends on how you want to setup your ignition and what kind of hardware tou want to provide timing and crank-position data.

fwiw: i'm starting out with a locked dizzi then migrating to a 32-tooth crank-wheel so i ca go waste-spark.

[CrUZida]

Exactly my point, why are they all so inflexible?

Why is what so inflexible?

If you mean why is MegaSquirt so inflexible, I have no idea.

If you mean why are most aftermarket ecu's so inflexible, ie, why can only Autronic and MoTeC run VVTi?
I assume thats a cost vs demand factor.

The cost to write and test the software such that its 110% perfect and will never be the cause of engine failure, vs the demand of people wanting it.

Now think of the amount of motors out there that people are playing with that need it.
The answer is very very few.

In a couple of years as more people start buying VVTi motors then the lower ecu's will adapt to this and build in controllers.


Its really only the JZ series motor that have VVTi that people are starting to play with, and even then I can only think of a couple of people who have gone standalone, most have piggybacked.
The UZ series are still quite expensive, as are the S series.

[CrUZida]

Hmm, could this be why the megasquirt has only been programed for use with a distributor ?

AFAIK there is no difference between an electronic distributor, and the current Crank/Cam angle sensor setup.

To the ECU its identical.