MFDs, vanbus and Arduino

[Gryffindor]

This is a bit of an update on my earlier post* under M59 - but perhaps better here instead - going a bit further with MFD displays and vanbus, plus a sprinkling of Arduino - in case anyone now or later finds it useful.

Many here have already upgraded their EMF A displays to EMF B units, and I will be doing the same. Some have wondered about the pinouts of their 18-pin sockets; it seems that only 5 are used and 4 of these must be for the bus; the fifth is a second +12v supply. But there has been talk of a further two pins being used, possibly for the external temp sensor which lives in one of the wing mirrors (for example https://www.berlingoforum.com/thread-799...l#pid96087).

* partial quote:

I thought I'd have a look at the inside of the [EMF B] I have waiting to be installed. Unless the pcb has more track layers hidden below the surface one (likely) which have tracks leading from the 18-way port's pins (I suspect not), then at first sight it does indeed appear that only 5 of the pins are used, but different ones:

Above diagram [see original post]
Pins 7, 9: +12V
Pin 8: gnd
Pins 4, 18: data

My MFD:
Pins 1, 3: both thick tracks, probably +12 V
Pin 18: medium width track - gnd? Not obviously linked to the pcb's general ground plane though
Pins 6, 8: each lead to groups of resistors and caps near ICs - data?
Pins 9, 10: each leads to one capacitor and then a plated-though hole, presumably making electrical contact with an inner track layer in the pcb. Function? No idea.

I would have expected one thick track for gnd and two medium ones for 12V.

[https://www.berlingoforum.com/thread-20066.html]

Here's some general photos of the EMF B pcb to go with the above description:

       

It is possible to see tracks under the paint in the rear view, and it may be tempting to try to 'join the dots' (plated-through holes) with the tracks on the front, but a PCB of this complexity may well have several track layers buried in it, so I haven't tried.

Here are two details of the front. I have numbered the pins (hope correctly? - remember this is in effect a mirror image) and added info on the chips where I could. I think that the entire area I've tinted green is for power supply regulation.

       

In short, I can't tell what the sixth and seventh connections do because they lead to plated-through holes.

Maybe others can do more with this. I don't have sedre - I wonder whether its wiring diagrams would show the MFD's individual wires or just the whole loom?

As for my guess at the remote key transponder chip, I had no luck with that chip's serial numbers except that one of them looks suspiciously like a PSA part number (but no hits come up for it), and trying just "JCAE" suggests that they are a mfr of MFDs and other related PSA components, plus I got JCAE hits in eBay ads for keys which also had part numbers very close to the number on the chip. See for example https://www.ebay.co.uk/c/1483448544 .


MFDs: "EMF A+ or CEMO"

Moving on, I also got distracted by a newer generation of MFD display. From my earlier post:

Then I got a bit distracted by a Youtube vid, wondering whether it would be possible to add a 'Peugeot type C' display instead of a 3-line 'EMF-B' MFD:

https://www.youtube.com/watch?v=WAU_yHYznWs

One intriguing point is that apart from the display's height, it looks otherwise quite similar to our MFDs - same width, screw fitting, etc.

Another is that once the guy has it installed, he then 'programs' it using the buttons on a standard PSA radio. It is a CD one whereas mine has a tape slot, but the other controls look similar. So, knowing from earlier threads here that the MFD and radio are linked anyway, would a type C display work in a Berlingo?

A third is that this seems to suggest that rather than the MFD controlling the radio, this 'control' function is not one-way. More on that in a bit...

The short answer appears to be no - they have different connectors with only 12 pins (see about 0:45 in the above video) whilst ours have 18.

I can now attempt a longer answer. First, having watched the vid linked to at the start of this quote, I noted that no ECU reprogramming was needed to upgrade from the later gen MFD to the even later gen MFD - it just worked. Plus, the ones they are upgrading from are plentiful and cheap on eBay right now (search not for EMF A as he says, but for "EMF A+ or CEMO").

So, if one of these cheap ones could be made to work in a Berlingo, then so could the other one (EMF C). And it being an EMF A+ whereas ours are EMF A may indicate some sort of shared architecture.

I bought a cheap one, and managed to find one with its connector plug and a short bit of the wiring loom still attached:

   

Incredibly, the wiring loom has just four wires in it - not even the supposed 5 of the EMF B. Clearly just the bus lines. In fact, if you look again at the Youtube video you can see that the cable for his MFDs also only has four wires.

Therefore, our MFDs having 18-pin connectors and these ones having 12-pin ones means nothing! (Putting aside the mystery two extra connections in ours.)

I wondered whether I could try to match the pins of my EMF B with this EMF A+ by comparing the pcbs, and just give this EMF A+ display a go as it is. Maybe there's even an option for it in Diagbox.

By the way, although its binnacle is very different, the display itself has similar proportions to our EMF Bs - the bolt holes are the same distance apart as far as I can tell, and the screen height seems to be very similar to the EMF B (both being a bit taller than our EMF A). So it would at least physically fit in a Berlingo as well as an EMF B would.

But before I got any further, I then made some new discoveries on tinternet, and this is where Arduino comes in.


ARDUINO and MFDs

In another thread of mine on 'nixie speedos', gadgetman suggested that an Arduino might be used to control a dash display:

https://www.berlingoforum.com/thread-200...#pid126605

Well, someone else had the same idea, managing to control one of the later gen MFDs with just a mobile phone and an Arduino - no car or ECU in sight:

https://www.youtube.com/watch?v=8nrd7SJgO-M

This could open up all sorts of possibilities!

It's a refreshing change to have such a short vid which tells you just as much as you want to know without any mind-numbing tedium!


VANBUS

This chap only has a few vids up so far, but they are all very interesting. In this one he uses I think a logic analyser to capture and display the vanbus signals to/from one of the EMF A+ MFDs:

https://www.youtube.com/watch?v=TvU9y1NNd5s

And here, he converts vanbus to canbus and as a result manages to get one of the later gen MFDs working in a 2002  Peugeot:

https://www.youtube.com/watch?v=Qk_8EhsqwUA

If you click 'show more' beneath the vid, he has put up links to some potentially useful if highly technical stuff on vanbus. So now we can add his contributions to the vanbus links roundup from my com2000 post:

New to me, so yet another distraction ensued... in short, PSA cars have a second internal bus network which is dedicated to what I'd call the human interface, including radio, dash displays, airbag ECU, and - crucially for me - steering wheel stalks, com2000s, and cruise control.

A few VANBUS links I found (very sparse):

• the above Peugeot thread in full
  
• http://jimbutterworth.co.uk/5bus.htm
  
• https://www.eevblog.com/forum/projects/v...2002)/100/
  
• https://en.wikipedia.org/wiki/Vehicle_Area_Network
  and its links to ISO specs and this site:
  
• http://graham.auld.me.uk/projects/vanbus/index.html
  
  

I even read in one post somewhere - can't find it now - that the MFD (any type) contains the brains of the VANBUS network - so those who have in earlier threads in this forum suggested that the MFD contains the trip meter processor because its chips are far too exotic just for a clock, it seems that you are right, but it also goes a lot deeper than that!

If it does contain the brains, could they be the large processor-type chip which I couldn't identify?

Might be useful to someone one day. Although it is now very clear that my idea of just splicing in one of the later gen MFDs would never work!!

Who is that chap?

https://www.patreon.com/user?u=27581008

Scroll down past the 'patron' fees and you'll see a little 'about me' box.


Lastly, there are a few relevant Youtube vids on canbus, for example

https://www.youtube.com/watch?v=4SgW64d_fbE
(Controlling an Instrument Cluster with an Arduino)

https://www.youtube.com/watch?v=q42XOnm4GwQ
(Peugeot Canbus Hacking)

[cancunia]

Very interesting collection of info, thanks for compiling. There are also green background displays as fitted to a C5 vs the usual orange which I thought was better during the day, but worse at night.

[Gryffindor]

Yes thanks; I remember reading the thread mentioning them. I get on alright with my orange two-liner on that score but TBH I have no idea what colour the three-liner waiting to replace it is!

The colour must be due to a coloured filter; LCDs are by nature sliver/black (almost). So it should be very easy to swap that filter sheet for any other colour you can think of if you can find it - coloured acetate, glass paints, Quality Street sweet wrappers...

There may even be scope for replacing the bulbs with a DIY LED board where the LEDS are RGB, then you could have a knob or pushbutton (one of those LED string remotes?) to change the colour at will... and the brightness...

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BTW I also remember people talking about black digits on a coloured background and vice versa - if what I used to do to pocket calculators at school in the 70s (yes, the teachers were that good then as well as now) is still valid, it would be easy for anyone to switch any LCD display over from one to the other.

There will be a plastic filter sheet over the display, probably in front of it, which looks like it does little else than dim it a bit - but it is a polarising filter just like Polaroid sunglasses, only allowing lightwaves in one diagonal direction through. If you reverse it, that should swap the black digits / black background over.

LCDs work by using a small electrical charge to literally twist tiny liquid crystals CW or ACW, so 'black' is one diagonal direction and 'white' is the other. They then twist the light passing through them, and the polarising filter blocks one of the two directions.

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I suspect but don't know that this may also be why a lot of people experience fading digits especially when their MFDs get warm  - the crystals' ability to twist degrades over time.

But if I'm wrong please shoot me gently!

I remember deliberately watching my LCD watch change time at school one day. It seemed a momentous thing back then to watch it clock up 12:34 on the 5th of June 1978.

Ah - new idea time... nixie wristwatch...

[Sol]

Excellent bit of research there mate!

Btw the C type display also used on the B9, has a setting called "video" which allows it to be inverted to black on orange, it's really bright that way at night but it does have dimming control.

I reversed mine, then put it back. Still undecided about which way I liked it best.

If I were you, and you seem to have a keen grasp of electronics, get ServiceBox on eBay, comes as a VM (virtual machine using VM player) and it is fantastic, costs under a tenner, don't install it on the same machine as DiagBox as it messes with that, but it is mega detailed to pin level. And you can click into things till you get to individual signals.

[Gryffindor]

Much thanks Zion. I left school knowing nothing, except that I knew that I knew nothing (if that makes sense). So one day I bought one of the hobby electronics mags, and before long I was buying most of them and had a couple of text books. For many years I thought the word Bible was spelt M A P L I N!

Of course what I did learn is now many decades behind the curve, especially regarding legislation, but at least I know it. Very interesting what you said about the LEDS in that fuse box BTW - got me wondering whether the basic principle could be used to make a bulb fail warning device for my little Berlingo. Best/simplest I've seen so far involves twisting the bulb's supply wire round a reed relay, but of course that only works when current flows, i.e when the bulb is turned on, and also I'm not sure whether that would add enough extra load to annoy the ECU.

As it happens I've already bought ServiceBox, mainly because the occasional screenshots of its wonderful diagrams posted on here make me drool all over my monitor!

But I must be disciplined - there's now a lot of things in the queue, including an instrument cluster, a wiper stalk end, the MFD of course, and more importantly determining whether my Diagbox installation is the full ticket (I have my doubts, to be resolved when next off work), and all of those have been leapfrogged by the need for new front brake discs. Underlined this afternoon by a successful (phew!) emergency stop on my way home.

[Sol]

The reason I mentioned ServiceBox, is that if you pick a model that has the display you want to use, it will show the pinouts in detail for the MFD if you drill down.

[Gryffindor]

That could - would - be very useful... he said, as he hatched a devilish plan... take over the world by controlling all its cars...

oh sorry - smart motorways have already been thunk of. Back to the drawing board.

[morcibacsi]

Hi guys, hi @Rasputin, I am the guy with the VAN bus research. If you have any questions regarding the buses, what is possible, and what is not I am happy to share what I found out until now. I am not an expert in Berlingos nor I have one however the communication buses inside the cars made by Peugeot and Citroen is pretty much the same.

[cancunia]

Hi guys, hi @Rasputin, I am the guy with the VAN bus research. If you have any questions regarding the buses, what is possible, and what is not I am happy to share what I found out until now. I am not an expert in Berlingos nor I have one however the communication buses inside the cars made by Peugeot and Citroen is pretty much the same.

Welcome to the forum & thanks for the offer of info which is always good to have. 
I am not brave enough to alter my wiring but I am sure there are others that will want to see what is possible!

[morcibacsi]

To answer some questions, and assumptions from the earlier posts. Regarding the pinouts on the MFD 5,17 are also data pins. I the Peugeot 307 data wires are wired through the display for automatic air conditioner ECU. So if you remove the display the A/C won't work as it loses connection with the BSI. Inside the MFD the chip with whe JCAE inscription is the main processor which handles the VAN data coming through the TSS461, and it controls the lcd driver.

The naming is a bit confusing as there are EMF-A,B,C displays for the VAN architecture (these are 18 pin displays). For CAN architecture they call the displays as EMF-A,C (these are 12 pin devices). They are not intechangeble in any ways as the communication protocol is completely different (that is why I had to build my VAN-CAN bridge, which as the name implies bridges the gap between the different architectures).
As you already figured it out, inside one architecture you are free to replace displays, it will work out of the box. However there are some functionality which can be enabled/disabled with Diagbox. Like for example the CD-changer or the trip computer info. These are coded into the display and if you remove it, or replace it with another one which doesn't have this functionality enabled you may need telecoding with Diagbox.

And this answer this assumption:

I even read in one post somewhere - can't find it now - that the MFD (any type) contains the brains of the VANBUS network - so those who have in earlier threads in this forum suggested that the MFD contains the trip meter processor because its chips are far too exotic just for a clock, it seems that you are right, but it also goes a lot deeper than that!

So the display is not the "brain of the VAN network" but it is the initiator for some messages (trip meter data, cd changer). The display queries the BSI for the data, which will reply with the trip info.

There was an assumption that a thermistor could be wired to the MFD to get the outside temperature. Well.. that depends as I said I'm not familiar with Berlingos but in the Peugeot 206 they had two generations. The first one didn't have a VAN bus, and the thermistor was indeed hooked to the MFD. However in the new generation (with VAN bus and CAN bus) the thermistor is connected to the BSI, and the display get the data which should be displayed on the network.

And indeed there are multiple buses in your cars as various functionality is separated. There is one which is responsibe for the instrument cluster, A/C, radio, MFD, parking assistance or comfort functionality if you like. There is another one for the airbag, COM2000, another for, alarm, electric windows. One for engine control, ABS, ESP. They are separated and the BSI acts as a gateway between them. Here is the picture of it (it's for a 307, but I am sure it is pretty much the same for Berlingos as well.)