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Replacing CRT with Tablet


Nittany

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1988 Reatta:

Here's a little thinking outside the box, but it's hypothetically possible and I believe Padgett may well be on the way to accomplishing this: consider removing your VIC and replacing it with a tablet.

We know that music, bluetooth and directions/maps/GPS are already available on a tablet. The challenge is to adapt the tablet to act as an HVAC system, ie to be able to convert what our Electronic Climate Control (ECC on a Reatta) does into instructions that our air conditioning and heating equipment will follow and send the correct air through the proper ducts.

Maybe this is worthy of a separate post and if Padgett/Moderators see fit, please move this. Yet, it is a viable option for all of us dealing with aging electronics and a desire to bring newer technology into our aging cars, and this is true whether you drive an Olds or a Buick or ?? I'm looking forward to what the tech-savvy folks who hang out here can come up with. I do have a '91 coupe that I am willing to experiment on so that we can put our ideas into reality if we can accomplish the HVAC capability on a tablet.

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Moved to a thread of it own.

On the one hand, the ALDL LAN is just a serial LAN with an oddball baud rate and packets are sent to various components. A long time ago I disassembled the BCM but never analyzed it (added mnemonics and labels to make it meaningful). There is a lot of information available but is not a trivial matter. I suspect it would take a Windows tablet since there are devices (moates.net) to convert and read the ALDL by a PC. WHAT to tell it is what we would need to figure out.

ALDLSTUFF.ZIP is a good place to start the HOW but need a commented disassembly of the BCM for the WHAT.

The other issue is that the CRT is a 4x3 device and most tablets are 16x9. On the plus side they are all touch screens now. The enclosed picture gives you an idea of the issue but I expect 7" Windows tablets by Christmas. And then there is the sunlight readable issue (part of the reason no CRTs in 'verts I'm sure.)

So it could be done and I know how it can be done but would be a very time consuming process for very little return and not much of a market. What would be needed is for someone to give Jay Leno an 88 or 89...

post-31022-143141883354_thumb.jpg

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Moved to a thread of it own.

On the one hand, the ALDL LAN is just a serial LAN with an oddball baud rate and packets are sent to various components. A long time ago I disassembled the BCM but never analyzed it (added mnemonics and labels to make it meaningful). There is a lot of information available but is not a trivial matter. I suspect it would take a Windows tablet since there are devices (moates.net) to convert and read the ALDL by a PC. WHAT to tell it is what we would need to figure out.

ALDLSTUFF.ZIP is a good place to start the HOW but need a commented disassembly of the BCM for the WHAT.

The other issue is that the CRT is a 4x3 device and most tablets are 16x9. On the plus side they are all touch screens now. The enclosed picture gives you an idea of the issue but I expect 7" Windows tablets by Christmas. And then there is the sunlight readable issue (part of the reason no CRTs in 'verts I'm sure.)

So it could be done and I know how it can be done but would be a very time consuming process for very little return and not much of a market. What would be needed is for someone to give Jay Leno an 88 or 89...

Leno wouldn't be interested. When he whisked by the Reatta Rally last year, he was asked about the Reatta. He said 'see me in 20 or 30 years'. If you view his site with regularity, Leno is interested in technology that fuels or moves vehicles. Other than that, he probably still uses a Motorola brick phone.

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Guest Mc_Reatta

Thought the HVAC commands went along with the radio commands on the E&C bus not the ALDL data bus. Hence the C in E&C.

As reported by Daniel, there has been progress in interfacing with this bus so that steering wheel controls can be used to control newer head units. You would need the opposite conversion function in converting tablet commands into data packs that can control the HVAC module in the car.

The folks who make the audio interface modules probably already have the knowledge of what would be necessary to do this as well. Just need to convince them it's a worthwhile pursuit.

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E&C bus is a 1000bps pulse width modulated communications path, so rather oddball compared to the ALDL line (which is a conventional async serial bus, the odd baud rate - 8192 - notwithstanding). Many MCU's can send/receive PWM communications, the trick is decoding the entire command set such that it can be reliably interfaced with by a programmable MCU. I see a high-end logic analyzer (like a scope but with additional capabilities to decode data streams beyond just showing the raw waveform) as the only means to unlock the secrets of this system. Have been toying with buying an older one second hand, but have not jumped in yet as I haven't many projects that would need this gear.

As far as the steering wheel adapters go, these are generally just reading the resistance value of a given switch (each steering wheel control in older GM applications has a specific resistance value) this is then run through an A to D converter which outputs pulsed commands that can be interpreted by aftermarket head units so that they can be programmed to respond to SWC presses. This works one way - SWC to aftermarket. I've not seen one that actually intercepts E&C command to communicate with aftermarket gear, but Daniel apparently stumbled onto something that works. I am now wondering if the radio command outputs from the CRT are simply represented as a variable voltage that is picked up by the adapter the same way it reads the regular SWC used in other GM cars of the same era as the Reatta (such as the Toronado or Bonneville for example). After all, PWM is essentially a means of simulating variable voltage by rapidly pulsing a given voltage (say 5 volts DC) on and of with differing on/off times to simulate a lower voltage than the one at the input. I am thinking this may be why Daniel's setup works.

Big problem is that we will be on our own to figure this stuff out as GM clearly has no intent or desire to publish the specs, even for an obsolete technology. It would be vastly easier if they would give us the specifications & design for this stuff, we could then start from a much better informed point to develop custom hardware. For the Reatta specifically, it is even worse because the CRT cars have another whole layer of hardware in the CRTC that is undocumented, and very much non-standard compared to other GM modules of the time. Reverse engineering the CRTC is the holy grail, but too few people have the right combination of time, knowledge, hardware and interest to crack it.

I have done some preliminary stuff with the CRTC firmware, all experimental at this point. I have a modified CRTC with sockets for the two program ROM's so I can test tweaked firmware without too much trouble. Also have a ROMulator that plugs in in place of an EPROM and simulates the chip, while running the firmware from a laptop with the ROM image loaded in real time. This allows for tweaks to be made in the code, and then immediately reflected in what the CRTC "sees" as the program code to be run. I've made some interesting discoveries, but have not been able to do things like add buttons/animations or entire new screens yet.

There is 64KB in ROM in the CRTC. Looking at the code from the two PROMS (32K each), one can pick out the various screen displays (text portions clearly readable) and other things like the bitmaps for the various icons and buttons as well as the character set data. I have yet to find the bitmap for the splash screens (there are two, one for Reatta, another for Riviera) and the compass display with the rear of a Rivi driving towards the mountains. I very much want to tweak the latter to look more like a Reatta, and would like to improve the splash screen/logo a bit as well. Then there is the matter of the cell phone screens (for the optional factory cell phone). These are useless now, and could be wiped and new screens added in the portions of memory that they presently occupy. However, I have not devised a way to "call" these screens in response to an on-screen button press so that is another dead end for the moment.

With the weather getting better, I will be more inclined to sit in the car with the laptop hooked into the CRTC and see if I can map out the rest of the ROM code to the extent that the above problems might be overcome. Until I can get a better picture of how it all works, I am left without the ability to do much other than superficial changes in the on-screen text.

KDirk

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Guest Richard D

As far as putting radio controls on the steering wheel, awhile back I saw an aftermarket system that used an IR transmitter that mounted to the wheel (it did not look as bad as you think) It could be set for aftermarket stereos that came with remote controls. You could also buy a receiver that would convert IR signals to make/break outputs that could be installed into factory systems. That would require some knowledge in electronics to wire it into the stereo. I have not seen the system in a year or so, I think it was marketed by Pyramid.

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Thanks for all your thoughts!

Originally I was offering this idea in response to 1988 Reatta who is working on his Trofeo. Anybody familiar with the Cadillac CUE (Cadillac Users Experience)system? It is a tablet that controls all the above mentioned functions . . . in fact, Cadillac even sends a new ipad to XTS purchasers so they can become familiar with operating the CUE system.

General Motors offers similar systems throughout the current lineup, ie Chevy calls it "MyLink", Buick calls it "IntelliLink". What follows is a "cut and paste description of Buick's version:

Simple, seamless, personalized – Buick’s IntelliLink1 system delivers a world of infotainment via the 7” high resolution, full-color touch screen radio. Its enhanced voice-recognition technology allows you to carry out a range of tasks with just the sound of your voice. And once paired, Buick IntelliLink becomes an extension of your smartphone. As intuitive as it is inspired, Buick IntelliLink will help you see and hear your driving experience in a whole new way.

I don't own a vehicle with the 88/89 CRT but rather I have 91's with enough space on the dash that the radio and HVAC controls could be removed and a tablet type screen could fit in nicely there. Hypothetically, if I bought such a unit from a wrecked GM car with the above referenced "Link" system, my question is what kind of interface or adapter might be necessary to allow the 2013 technology to work with the 1991 equipment? I'm thinking the Radio/Bluetooth/smartphone/GPS connectivity is already being offered by aftermarket companies, is there an aftermarket company or some way to allow the system to operate the HVAC as well? Alternatively, simply just find a GM HVAC control unit that might fit into the "storage cubby" of the 90/91?

Again, I know I'm doing some wishful thinking rather than truly offering a solution to 1988 Reatta's issues, but is it possible? (I think so) Is it affordable? (Not so sure) Does anybody want to try it? (Yes, on my coupe to start, not my vert!) And, how would we go about it?

Keep the thoughts and ideas coming!!

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FWIW...I spent just over 2 hours (140 miles) in a Tesla yesterday (15 minutes behind the wheel) and that car has changed my mind about electric vehicles. Unbelievable pick-up that can get you into trouble because the feedback is practically non-existent. In the short time driving I couldn't get comfortable with the car (due to its lack of 'noise') but as a passenger, it was bliss. Like being transported on a cloud.

Getting onto the subject of tablets, Tesla relies heavily on the use of a tablet. I've played with Cadillac's latest CUE and it's not bad but its features are nearly identical to my 2007 Lexus (but a significant improvement from my 2009 XLR). But Tesla...they have spanked the competition.

Model S Features | Tesla Motors

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