Retaining Clock and Trip Controls with Aftermarket Head Unit?

[Bingo]

I made the mistake of driving a car that had Apple car-play. That one's on me. Now, I need a double din head unit with car-play. Now I already have a mounting kit, and the steering wheel controls seem easy enough to figure out, but all of the threads I've read regarding maintaining the clock and trip computer controls from the top row of buttons, people just give up and get rid of them. I know the '06 and up Mazda 3's had an independent harness for that LCD screen which leads me to believe that those buttons can be salvaged. Before (although I absolutely can and will) tear apart my dash looking for a solution, has anyone out there successfully done this? I've seen a video of someone using an Eonon head unit re-purposing steering wheel controls to control those functions, but I'm under the impression that that capability is specific to that head unit? I'm not willing to compromise stock functionality for car-play, and I'm no stranger to electrical work.

[Bingo]

Alright so I pulled apart the radio and LCD screen and there's a single harness consisting of 12 wires running from the radio circuit board to the LCD screen. I can identify the power (and ground) no problem, but the screen and board need power for me to see which wires the buttons send power through. I apparently made an incorrect assumption that I could power it off of the cigarette lighter and fried the LCD screen's circuit. Now I'm just reaching out to see if anyone has a pin-out diagram for the circuit or harness? Thankfully I fried the screen I just pulled from a junkyard, but I'd prefer to not have to get another. The service manual does not go into detail about the wiring or circuitry for the radio.

[superspeed27]

To the best of my understanding what is shown on that trip computer is controlled by the CAN bus. So to retain the ability to change them you would need to figure out what to send over the CAN bus, which I believe is what the Eonon units do.

I'm not sure if this person got an farther, but they managed to get something working with an Arduino and a CAN Bus shield.

https://youtu.be/WvvZS6Drc_o

[Bingo]

I'd be interested to see what he did. I broke down and got an Eonon which works, but is missing some of the features of Pioneers. I'd be willing to continue working on this but in truth I don't have a great place to start. My thoughts were to find what physical wire in the harness sends a signal to that LCD when the info/clock button is pressed and measure its voltage and duration and replicate it with a new button with supplied 12v (and a voltage stepped or delay times as needed).

[superspeed27]

I'm going to look into it some, but it looks like a lot of work. If the youtube fellow is willing to share his Arduino code I might be able to do something with it since I happen to have some experience with them. In the comments he says he gave up after he ran into an issue of reactivating the trip computer after a battery reset.

Since its all CAN Bus stuff the solution would have to be able to replicate the machine code (1's and 0's) that goes over the bus. Which makes me think an Arduino would be the most elegant solution. I've read of several people setting the radio stuff with the stock HU then plugging in the new HU.

Out of curiosity which Eonon did you get, and how do you like it? If I can't get anything figured out with this I'm probably going to go with one of those.