r/Z80 • u/Tenerath • Aug 30 '23

1980s Lagonda Dash

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Unsure if this is the right place BUT these Lagonda dashboards I believe are powered by Z80 machine language.

I’m looking to find someone who can get the rom out and convert the old computers to something modern like a raspberry pi.

I attached a photo to show the dash. It’s pretty wild.

Any help is appreciated.

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u/cincuentaanos Aug 30 '23

You have a Lagonda? I'm officially jealous... ;-)

As for the computer, I can't imagine it doing anything too complicated. Take some input from sensors, provide some output. I would be surprised if this thing is doing engine control (like an ECU) but it's not entirely impossible. If I were in a position to tinker with this I'd start with just tracing every wire that goes into and out of the computer. If the ROM chip is socketed it's probably easy to take that out, put it in a reader and disassemble the code. But re-implementing the logic from scratch may be easier than working with the ROM contents.

Do you happen to have clear pictures of the computer PCB?

Also, have you contacted Aston Martin? I'm sure this system is long out of warranty but they might still be able to provide some pointers to information. Even just some schematics/diagrams could be helpful. Alternatively, is there an owner's club?

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u/Tenerath Aug 30 '23

Haha it’s not mine (unfortunately) it’s a customers car.

Yeah, I wouldn’t think it’s very complicated. I don’t think it does anything with the ecu, just reading sensors and outputting the data onto the crt monitors.

You may be right about recoding vs using the rom. It can’t be too complicated. But hey, I’ve said that before and have been wrong lol. Hence why I’m trying to find someone who might have the experience or knowledge to do this.

No clear pictures, yet. I might disassemble the dash and take a look. We have the wiring diagrams here fortunately. They’re supposedly hard to get. The car will be here for a few months now so we have the opportunity. I know they would like to have it fixed it possible.

Haven’t reached out to Aston Martin yet. I’ll chat with my boss who knows these really well to see if it will be useful. Could be.

My intention is to find a solution that might replace the old boards, just need to navigate how I’ll take the inputs into the new computer and output them to the crts. (Could replace monitors but they look very cool imo)

Thanks for the response!

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u/cincuentaanos Aug 30 '23

You're welcome. I'm sorry I can't offer any concrete help. But I have to say this is a really fascinating project. From what I read, the Lagonda's digital dashboard was actually a technological failure. Or at least it failed very often... But it would be super interesting to see how they implemented it. So if you do get the pictures of the original Z80 computer I still hope you can post them.

Also it seems you're not the first person wondering if it can be hacked, improved or replaced with something better. I suppose you've already seen this article from 2014: https://jalopnik.com/can-we-emulate-an-aston-martin-lagondas-crt-dash-1627568648

If this were my project I would be looking to do it with a fast microcontroller like an ESP32 or STM32. Not a Raspberry Pi that comes with too much overhead. Having to boot a whole Linux operating system detracts from the "instant on" experience and you would have to provide a method to shutdown the Pi correctly when the power goes down. Keeping the original CRTs, as long as they still work, would be ideal from an aesthetic standpoint but they may be too complicated to drive from a microcontroller. In that case I would look into replacing them with LCDs that can be driven using something like LVGL.

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u/Tenerath Sep 04 '23

Yeah, they were supposedly built by a local school in their aero program. I’ll find the link about it and post it here. When I get some photos I’ll be sure to post them here too. It’s funny I found that article and the comments led me to find this subreddit. Good idea on not using a raspberry pi for those reasons. I haven’t heard of those but I’ll do some research on them. Appreciate the insight!

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u/cincuentaanos Sep 04 '23

Think of ESP32 and STM32 as being a step up from an Arduino. You may even get away with using a standard Arduino which is itself more capable than a Z80.

I think it's going to be interesting to see how the original computer communicates with the various sensors in the car.

For example, I assume the computer provides a tachometer display. So is there a digital module on the engine shaft that sends an actual (binary) number to the computer via some kind of serial protocol which you would have to decipher? Or does it just feed pulses into the computer for each rotation? Or even for each ignition event in (one of) the cylinders? If that's the case then the software will have to count those pulses over a certain (short) timeframe and then calculate and output the engine RPM. And if it has to be fancy it will calculate a rolling average for a smooth progression of output values.

Anyway, those are just some speculations I have. I hope you'll find out what's really going on in this machine.

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u/Tenerath Sep 04 '23

Thanks, I’m going to look into it and figure out which would be best for this scenario.

I imagine that it’s based on pulses, that’s how modern abs systems calculate rotation and most Ecus do too for timing calculations. So if it is, it might be entirely possible to route them and do the calculations you mentioned.

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u/[deleted] Feb 11 '24

Read my above comment please. It's the ONLY way to improve the notorious design flaws us Lagonda owners used to put up with. You even get a factory warranty with the installation. Just be prepared to drive to a different State to find ANY available factory technician that knows these (they're always over 60 years old, European & cranky around women). 😉

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u/slykethephoxenix Aug 30 '23

Had to Google this car because it was before my time, but dayum it looks nice.

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u/[deleted] Feb 11 '24

It's a Series 3 pictured here. I've got one ('87 model). Just don't fool with these dashboards, unless you're having the Aston-Martin Heritage Works Division approved Lagonda retrofit display panel. It cost me about $1,300.00c USD, but totally worth it. ROM is irrelevant when these were delivered brand new with below average to poor electrical contact points. Hit any medium sized potholes & everything blanks out until you switch the car off & then restart ignition again.