Question on CAN wiring

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Question on CAN wiring

Postby Talkiet » Wed Dec 27, 2017 5:53 pm

I have a MS2/v3.0 that I didn't build. It's driving a Toyota 4AGE and there is an RX7 daughterboard (I am not sure what that does) and there's some stuff on the proto area (looks like a relay control circuit I think - not 100% sure)..

My issue is that this proto circuit connects to SPR1(CANH). I presume this is just to break it out to the DB37 but again - not sure and I haven't traced that wire in the loom yet. I also haven't checked to see where it comes from on the board so I could look at that in the config. (yet)

Note that JS6 and JS8 have nothing connected to them.

Am I right in assuming that SPR1 and SPR2 (CANH/CANL) are only named that way for convenience, and that unless connected to JS6/8 they have no special use at all except as a path to the DB37 pins 3 and 4?

Given SPR1 is used, and JS6/8 are not used at all, could I simply take JS6 and 8 to a new 2 pin connector and use that as my CAN bus connector? (and leave SPR1 doing whatever it's doing right now?)

This all seems reasonable to me but I have read the docs and thought I would make sure. I have found in the MSGPIO docs this description...

Code: Select all
On MS-II™ controllers, the CANbus circuits are:

CANH: CPU pin PM0 (#45) → 40-pin socket pin 6 → JS6 jumper to SPR1/CANH → DB37 pin 3,
CANL: CPU pin PM1 (#44) → 40-pin socket pin 11 → JS8 jumper to SPR2/CANL → DB37 pin 4.


Which seems to indicate that I could intercept before SPR1/SPR2.

Cheers - Neil "Got the soldering iron on standby waiting for confirmation" Gardner
Talkiet
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Re: Question on CAN wiring

Postby jsmcortina » Wed Dec 27, 2017 5:56 pm

Talkiet wrote:Am I right in assuming that SPR1 and SPR2 (CANH/CANL) are only named that way for convenience, and that unless connected to JS6/8 they have no special use at all except as a path to the DB37 pins 3 and 4?

Yes.

You'll find the schematics of the board in the current Hardware manual under the "Manuals" link above.

James
I can supply, repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: viewtopic.php?f=104&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
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Re: Question on CAN wiring

Postby Talkiet » Wed Dec 27, 2017 9:37 pm

Thanks for that confirmation. ALso had a note on FB and got the confirmation as well... Just to put useful info here in case anyone else ever searches for this question...

Canbus.jpg
Canbus.jpg (167.37 KiB) Viewed 54 times


Car back together with 2 pin connector added and still works - now to find a quick arduino Canbus logger or dash app to test.

Cheers - Neil G
Talkiet
MS/Extra Newbie
 
Posts: 31
Joined: Sat Dec 31, 2011 4:52 pm


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