john banks

Atmel ATmega128 MCU • 128K Program FLASH, 4K Static RAM, 4K EEPROM • dual level shifted UARTs • RS485 on-board • I2C ready w/pull-up resistors installed • up to 53 digital I/O pins • Selectable clock frequency of 16 MHz or 14.7456 MHz (select at order time) • Advanced, low drow-out voltage regulator on-board accepts 5.5-15V input with reverse polarity hookup protection • Small size at 2.2 x 3.6 inches

It is $125, and could be programmed in BASIC or C very easily. Pretty much able to talk to an ECU without any/many external components....

DIY Piggyback? Nitrous controller? Water injection controller? Boost controller? Knock controller? MAP to MAF converter?

Looks complicated to the uninitiated, but if you've ever done any basic electronics and BASIC programming they are a doddle to use.

[Edited by john banks - 1/9/2004 7:16:02 PM]

Delboy2

Looks interesting

David_Wallis

53 IO...

only downside for some by rs485 vs rs232.. not a problem for some

Pavlo

David,

Dual level shifted Uarts would cover serial would they not?

Very interesting.

With a few amps, it could be a complete ECU...

Paul

David_Wallis

Depends how much programming it requires I suspect..

David

Pavlo

One more thing, where do we get it?

Delboy2

HERE Even cheaper if you bulid yourself

The Fixer

Wouldnt fancy a zx81 looking after my knock control

Conrad

Pavlo

Andrew,

Surface mount, no thanks!

Conrad,

Probably more power than your ECU if it's only doing a single job.

Paul

john banks

Conrad, the same Flash area as a 99/00 ECU, and 16 million instructions per second is more than enough for most projects, and if not there are other boards with more memory.

Mega Squirt projects (there is an AVR version) confirm the sorts of things that could be done.

The attraction is the easy wiring, compact size, good spec chip in a surface mount config without the hassle. Would need absolute minimum of components to do all sorts of things.

You don't need a Pectel for a lot of things like challenging you on the quarter or at least trying , and then you can augment a cheap ECU with something like this.

David it has 5 different UART modes including RS232

[Edited by john banks - 1/9/2004 11:16:42 PM]

David_Wallis

John,

You and I dont have a chance of challenging conrad on the 1/4

Pectel requires a lot less programming.. have a look at the spec of a t10s.

David

john banks

Did I say it was with this car?

The Fixer

John, Paul, I understand what you are saying but I thought the general idea was to avoid all this "override" boards ala Japanese tuning methods and just put one thing in (ECU) thats upto all the tasks and was originally designed for that specific task. The more add on boards, the more problems could arise, the more complicated fault finding becomes. Sometimes its better to keep it simple. Sure if costs are an issue and ECU replacements are not possible then it will make for a good add on. I personally think you'd be better ditching the JECS, putting a proper ecu in, ditching the MAF and reap the benefits of that 2.5 of yours. All this time spent messing around with MAP to MAF conversions is money wasted, get yourself an ECU But thats only my opinion

Conrad

AndrewC

I've looked at these before, but found that the Mega128 is a bit OTT for the projects I have been playing with, also when developing projects it's not uncommon to blow components so surface mount is a bit of no-no for me, with all the AVR Mega series having I2C and SPI in hardware it's very easy to build up a network of smaller chips for multifunction projects.

Andrew...

john banks

Conrad it has not been that much time actually put into it although it has been over a long period, I've had other things to do, and not the immediate need until a few weeks ago and now I have other delays.

Besides I do actually enjoy fiddling with this stuff.

With a system like this you can put loads of features in it. I've not seen an ECU that allows you to write scripts to get it to behave in any way you want.

A customised immobiliser would be a few lines of code away for example. Four extra injectors would be quite easy. Closed loop fuelling learning across the whole range could be implemented.

With JECS running off MAP/charge temp along with a J&S there are not many features that are missing out of a far pricier ECU, and if you do want them you can write the custom stuff to do it, which is nice if you are interested in it.

We overestimate what we need out of an ECU, AndyF had the UK 1/4 record for ages on a STANDARD ECU - not even reprogrammed!

Andrew makes a very good point about blowing things up though.

The Fixer

John, it is powerful no doubt, please dont talk to me about writing scripts, I hate the damn things, do it for a living and somehow something or some condition gets missed out and bang, it turns into a minefield.

If you enjoy it then why not, I certainly do not have your patience and thus try and buy something that already works (or so I thought ) No point reinventing the wheel.

Conrad

john banks

Maybe if you tried your hand at a bit of minor surgery you'd quite like it, not as heavy work as working on cars, and it is not as offensive as gear oil

I don't do anything IT related for a living, so it is "fun" to me.