Hi everybody,

I would like to build a MM decoder in order to decode messages coming from an Ecos with the hope to be able to control a Fleishmann N turntable with 48 possible roads. It isn't great to do it with DCC as the Ecos only sends one message to change one road at a time with a delay of 3,5 seconds in between each change.. So when I wish to turn by 180°, the "bridge" turns 24 times 3,5 seconds, over 84 seconds, not only it is very slow but at each road we have an annoying clac clac noise..

I found some libraries for the Arduino to decode MM messages but it is probably outdated, I am not getting really what I was expecting.

The library reacts when MM messages are forwarded on the BUS but I can't decode the message properly. The code I have expect 9 trits to arrive twice for each message, so 18 bits, but the only document I found has an interpretation of the Message which doesn't not sound coherent with the messages received from the Ecos...

So I am looking for some help there

Thanks in advance !

Charles

The MM format developed in 3 satges. First in 1985 with 1 function, headlights. Then with up to 4 functions, telex couplers, or smoke, whistle, or horn. Then the FX extended format available with the 6021 control for as many as 6. When MFX debuted in 2005, with the first mobil, and central station, several more functions became the norm. Now we have up to 32 with the latest MS2 software, and CS3.
The ECOS 2 still utilizes railcome, which MFX does not, but the latest ESU M4 decodrs are both formats, so you don't really have to build a decoder, you can program empry ones if you wish, or buy them already so.
ESU and Marklin teamed up to develop the first central station, but then parted ways.

Hi, the reason I wished to build a very simple MM decoder was to benefit from the difference the way the Marklin 7686 expect messages from the Ecos or any Marklin CS

With a DCC decoder setting in the Ecos for a Fleischmann turntable, if I want to rotate the "bridge" of the turntable by 180° The Ecos sends 24 messages "go to the next position" and each time The Fleischmann turntable stops at the next lane, waits, then restart. Each time it starts again there is a solenoid used to free the "bridge" which makes a loud "clac" noise. I looked if it was possible to remove the index mechanism which locks the "bridge" in place but then the gears are not precise enough to have a very good alignment of the rails with the "bridge" so it needs to be kept.

When (in the Ecos) the turntable is set to be a Marklin 7686, to go to the next lane the Ecos sends only one message. To go to the lane #N, it sends only two messages. When the decoder receives the two messages he can decide in which direction it needs to go to optimize the "jump" and also pull the index mechanism only once, start the "bridge" motor slowly, then fast, then slow down when it reaches the position, then release the index... Virtually no noise. Of course there is a need to count how many lanes we cross, so I will need to have a little system with magnets and a sensor to be added, but this is very easy. All this is impossible with any DCC or Motorola decoder.

Writing my own code can also enable me to control the polarity of the rails to avoid shorts... remember... 2 rails and not three.. And also enable me to add lights in the little motor compartment, add a beacon to indicate the bridge turns, have real stop & go lights on each side of the bridge....

However there is still an Issue which I don't know how to solve yet... The Fleischmann has 48 possible roads and the Marklin only has 24... And, of course, in the Ecos we can only configure 24 roads...

I hope there is a trick... to avoid stops at each road I need MM messages... The TT-Dec knows how to listen to Marklin messages and it can address the 48 lanes of the Fleischmann turntable, but I don't know how to configure the Ecos to make all work....