I was afraid of that. Looking at this post http://www.grandprixforums.net/threa...pin-out-needed I did not see the Hi/Low for CAN. Looking at thumbnail 2 it had VSS Hi/Low. I was assuming vehicle speed would be a range and that might be a CAN. I have not found a BCM pin out yet, maybe because 97 does not have one! Without probing we don't learn. :-)
Option #1
AE J1850 VPW (Variable Pulse Width at 10.4/41.6 Kpbs, single wire) Pin 2: BUS+ signal
Idle bus level is low
High signal voltage level: +7V (min/max 6.25 to 8.00)
Low signal voltage level: 0V (min/max 0.00 to 1.50)
Up to 12 message bytes, excluding frame delimiters
Bit Timing;"1" Bit: Signal low for 128uS or high for 64uS
"0" Bit: Signal low for 64uS or high for 128uS
Start-Of-Frame: Signal high for 200uS
Option #2
ISO 15765 CAN (250kbit/sec or 500kbit/sec) Pin 6: CAN high (CANH)
Pin 14: CAN low (CANL)
Dominant or active bus state: CANH driven high while CANL driven low
Recessive or idle bus state: CANH and CANL signals are not driven
CANH signal voltage level: 3.5V (min/max 2.75 to 4.50)
CANL signal voltage level: 1.5V (min/max 0.5 to 2.25)
I have not looked at my DLC yet to see what pins are available. Sounds like I going to see option one and not two. :-(
On one hand that is ok because the papers say something about not all CAN are exposed at the DLC. They also said for example the PCM is built from a lot of ECU's in one box. The CAN bus maybe internal. Again :-(
Hence the reverse engineering. :-)
Interesting, I may have to digest this a bit. The interesting thing on the MCP2515 is it had a version that is "SPI" standard. The new Raspberry PI kernel has "SPI" integrated into it, and there are python examples already existing. Not sure how much latency would be added by using the "ST" commands. The specs on the processor sound interesting.
Just to learn, and hack around. Not sure what I can accomplish yet without knowing what I can do. If I did not ask, I would not have known about the STN1110 option.
Maybe the ultimate goal would be to have a Raspberry PI, touch screen LCD stack, in my 97 GP, that could display/control various functions. Maybe even be able to create a "Ad Hock" wan to phone app to remote control and get sensors reading. I mean that is way, way, way down the path. I have several pieces to go before that. It just feels like they are there if can be strung together. I have a remote start kit that uses relays for the remote start and doors. I could use the PI to control relays if can not be done through existing communications.
This is just learning what can be done.