GM: Car Port for XT4 2023

[garrettpall]

Car
Cadillac XT4 2023

Route
162796f1469f2f1b/00000005--6f334eda14

Checklist

• added entry to CarInfo in selfdrive/car/*/values.py and ran selfdrive/car/docs.py to generate new docs
• test route added to routes.py
• route with openpilot: 162796f1469f2f1b/00000005--6f334eda14
• route with stock system: 162796f1469f2f1b/00000003--79f5d5854f (old harness design)
• car harness used (if comma doesn't sell it, put N/A): N/A

[github-actions]

This PR has had no activity for 30 days. It will be automatically closed in 7 days if there is no activity.

[garrettpall]

Panda and Openpilot PR rebased 12/21. Have not tested yet, but will once requested. This Car Port requires a new harness to be made.

Mouser #:	Mfr. #:	Desc.:	Order Qty.
571-1-1703930-1	"1-1703930-1"	Automotive Connectors NANOMQS	20
571-2309644-4	"2309644-4"	Automotive Connectors Automotive Connectors 30P NANOMQS/US050 LL CONN, W/CPA, KEY D	1
571-2236905-1	"2236905-1"	Automotive Connectors Automotive Connectors NANO TAB 0.5X0.4,TERMINAL	20

[garrettpall]

This PR would also support adding the 2019 Chevy Volt as a supported car.

[garrettpall]

https://github.com/garrettpall/GMSDGMConnector/blob/main/Connector.stl

[adeebshihadeh]

How does the harness work on this car? Does it require unplugging the ASCM like the currently supported Volts or is this a normal setup (i.e. does it completely fall back to the stock system if the C3X is unplugged)?

[garrettpall]

@adeebshihadeh The ASCM does not get unplugged/bypassed and AEB is retained. This means longitudinal support is with the stock ACC system. The harness only intercepts the powertrain bus at the SDGM (serial data gateway module) under the dash above the obd port as the camera only has the object bus.

[garrettpall]

This port is confirmed working on a 2022 Chinese Buick baby enclave (Envision-ish) too with fingerprint forced to XT4.

[github-actions]

Thanks for contributing to openpilot! In order for us to review your PR as quickly as possible, check the following:

• Convert your PR to a draft unless it's ready to review
• Read the contributing docs
• Before marking as "ready for review", ensure:
  • the goal is clearly stated in the description
  • all the tests are passing
  • the change is something we merge
  • include a route or your device' dongle ID if relevant

[garrettpall]

So far only the XT4 has a steering cutoff of 30 mph. Every other SDGM car has been 6 mph

[garrettpall]

I think I found a way to make the SDGM port almost identical to the CAM car port. Just need a harness wiring change that I will test this weekend.

[garrettpall]

I have tested the new harness design and updated this PR. I currently have chassis hooked up to bus 1 in my car to gather data on brake messages, but will be switching to object soon. I recommend object be connected to bus 1 for future use (ie. possibility of corner radar points and front radar point to support a SDSU type hardware to get op longitudinal support).

Not only does this new harness slim down the port even more, but it also removes the comma from the middle of the main PT bus.

Harness can be seen here: https://github.com/garrettpall/GMSDGMConnector

[sshane]

We've moved the car interfacing code to our opendbc repository, which is now the new home for car ports and fingerprints. Please re-open your pull request against opendbc at your convenience by using this command below. This will transform all changes under selfdrive/car/ to opendbc_repo/opendbc/car/. Make sure you have initialized submodules beforehand and have checked out the latest opendbc commit.

PR_NUMBER=33045
curl -L https://github.com/commaai/openpilot/pull/$PR_NUMBER.patch | sed -e 's/selfdrive\/car/opendbc_repo\/opendbc\/car/g' | git apply -v --reject

Simply replace the PR number with your own. Once done, add the files, fix any conflicts, and open a new PR. Alternatively, you may start a new PR from scratch if that is easier for you.