CAN Bus Communication with Megasquirt 3

[jacob80]

Hello!

I am working on a project which will fetch engine status data (RPM, coolant temp, etc.) from the Megasquirt 3 Box via CAN bus.

I'm just getting into the CAN bus stuff, but wanted to clarify and confirm that I can, indeed, ask Megasquirt to send, say, a coolant temperature over CAN bus to my device.

Is there any issue getting this type of information from the Megasquirt box?

Thanks for your assistance!

[93white3400z]

Of course you can! You have access to the whole outpc data which is equivalent to the "A" serial command.

[jacob80]

Of course you can! You have access to the whole outpc data which is equivalent to the "A" serial command.

That's good to hear!

On top of this, is the CAN interface Megasquirt uses the same protocol as ODBII CAN communication interface?

[93white3400z]

Nope, not at all

[racingmini_mtl]

You should have a look here: http://www.msextra.com/doc/ms3/can_tech.html.

Jean

[jsmcortina]

See also
http://www.msextra.com/doc/pdf/html/Meg ... 3-247.html
and
http://www.msextra.com/forums/viewtopic ... 25&t=53115

For a new project that only needs to read data, I would suggest going the standard 11bit header route and enabling the new broadcast feature.

James

[jacob80]

See also
http://www.msextra.com/doc/pdf/html/Meg ... 3-247.html
and
http://www.msextra.com/forums/viewtopic ... 25&t=53115

For a new project that only needs to read data, I would suggest going the standard 11bit header route and enabling the new broadcast feature.

James

James,

Thank you for your quick response. I assume these documents break down this 11-bit header and broadcast feature set.

Is writing over CAN bus ideal? Or is RS232 still the preferred method? I've only written to my MS box via serial, and this Megasquirt 3 is brand new to me!

[jsmcortina]

For tuning your Megasquirt, stick with serial.

For simple configuration of an add-on that want to read some data, the new CAN broadcasting should be more compatible with regular CAN library code you are likely to find. The Megasquirt CAN protocol is proprietary and quite different with a steeper learning curve.

James

[jacob80]

For tuning your Megasquirt, stick with serial.

For simple configuration of an add-on that want to read some data, the new CAN broadcasting should be more compatible with regular CAN library code you are likely to find. The Megasquirt CAN protocol is proprietary and quite different with a steeper learning curve.

James

Thanks James, good information right there.

So tuning Megasquirt, stick with serial. Got it.

How about controlling fans, nitrous, etc? Can you do this over CAN bus? It'd be cool to have a push button device that tells Megasquirt to do things at the push of a button.