Chinese full screen IPCs software (GM)

[morfi]

I’ve noticed aftermarket “digital instrument clusters” on ali* which are, allegedly, fully plug-and-play.
Does anyone know whether their firmware is written from scratch — using reverse-engineered GMLAN messages from the OEM IPC, or if they’re built on top of a public library?

I’ve long wanted to build my own IPC dashboard with a completely custom UI, but I’d still like to preserve things like warning lights and fault-code display without starting entirely from zero. Ideally, I could buy one of these ali* clusters and swap in my own software while keeping the existing display, bootloader and hardware.

Has anyone tried this kind of modification or otherwise experimented with these digital clusters? Any tips or insights would be greatly appreciated

[Gatecrasher]

I don't know much about the Chinese clusters, but I've got a couple of all digital Cadillac XTS clusters I've been sitting on for a few years. I've done a lot of poking around in those and the 8" analog + LCD clusters. The graphics software is, of course, proprietary and expensive to license. You can dump the individual graphics from them, but in order to change the layout or functionality you'd need to reverse engineer the binary blob that controls that, or replace the underlying software completely.

The GMLAN and power management side is handled by a V850 chip. It also controls the physical LED warning lights. It packages up the bus data and sends it over to the iMX Linux CPU for use by the display software. In my mind, it'd be relatively easy to tap into the V850 data stream and pass the data up to some open source graphics software. I know there are a few out there, but I haven't gotten very far into seeing what it would take to adapt them. Conceptually it shouldn't be that different from setting up a sim racing dash.

I'd be really surprised if the Chinese clusters have a dedicated bus interface processor though.

Regardless, I'm really interested to see what you find out.

Maybe see if you can get hold of a firmware update bundle for one before you buy the hardware? Assuming it's not encrypted (unlikely) it should tell you everything you need to know about the software.

[morfi]

Maybe see if you can get hold of a firmware update bundle for one before you buy the hardware?

Good idea, I'll give it a try

The GMLAN and power management side is handled by a V850 chip. It also controls the physical LED warning lights. It packages up the bus data and sends it over to the iMX Linux CPU for use by the display software

It'll be my first time with bench IPC and I've yet to figure out the minimal setup. The IPC connector suggest that apart from GMLAN and MOST there are a few indicators (washer fluid, coolant and ambient temp) that have their own pins. I was wondering if I'll need a real BCM/ECM/?? to control what IPC displays (messages, indicators, warning lights, odometer, engine rpm, speed, etc) or will I be able to get away with custom externally controlled gmlan module. The number of pins on the ipc connector scares me...

[Tre-Cool]

Very interested to see how you go with it. I've certainly thought about it too. Trying to talk a mate with a camaro into getting one.

However i thought the dash cluster used low speed single wire & wasn't CAN?

[morfi]

However i thought the dash cluster used low speed single wire & wasn't CAN?

If I read the connector specs right, it does in fact use a low speed gmlan. By "CAN" you mean high speed gmlan or some other bus?

Here's a full pinout. I actually wonder why there are four gmlan pins. While I understand multiple VCC/GNDs for power distribution, what's the purpose of multiple data pins? Is it perhaps so that instrument cluster can also act as a junction box so that harness won't need splices?

pasted-file-NNKNU7.png

[MPC001]

However i thought the dash cluster used low speed single wire & wasn't CAN?

If I read the connector specs right, it does in fact use a low speed gmlan. By "CAN" you mean high speed gmlan or some other bus?

Here's a full pinout. I actually wonder why there are four gmlan pins. While I understand multiple VCC/GNDs for power distribution, what's the purpose of multiple data pins? Is it perhaps so that instrument cluster can also act as a junction box so that harness won't need splices?


pasted-file-NNKNU7.png

Looks like it is GMLAN in and out. HS GMLAN/CAN TCM's for example are typically the same. Like ECM >> TCM >> DLC or other in/out ECU. And/or Single wire LS GMLAN sometimes is wired in a star format.

[Gatecrasher]

That's an interesting pinout. It mostly matches up with mine. I don't know what's up with the multiple GMLAN pins though. I've only ever used one. It's worked on every Global A cluster I've tested.

GMLAN is a low speed, single wire version of CAN that uses 29-bit headers.

IPC pinout.gif

In order to wake it up and talk to it, you'll need something that can send the initial high voltage wakeup signal, and then normal 29-bit messages after that. That'll get you probably 90% of the cluster's functionality. You shouldn't need a BCM yet. You don't need MOST unless you want to do stuff like show music track data that would come from your radio, or contact names from your phone.

You might also want to get some steering wheel controls to page through menus and acknowledge error screens, but that's not strictly necessary when you're just getting started. It's easy to add those on later.

You should be able to get a bare bones setup working with 4 wires. Constant power, switched power, ground, and GMLAN. You can reconfigure it via DID settings to get the tach signal from GMLAN. You can add other stuff later if you need it.

[Tre-Cool]

I would bet HSCAN is used for ECT/Fuel/RPM/Speedo/Gear indication if auto.

Indicators, hand brake, low/high beam/fog etc would come via GMLAN

[Gatecrasher]

I've never seen a pre-Global B cluster with high speed CAN.