Joined: 16 October 2008
Location: IT
Posts: 2

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hi, what type of decoding comes made on-chip from mlx90109? manchester but what kind? diphase coding? I need a diphase coding so the speed pin is set to 2k or 4k? and modu? or the solution is that I make my diphase codin by external processor and mlx90109 give me a non decoded signal....

Joined: 1 February 2006
Location: CH
Posts: 109

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Dear,

The MLX90109 integrates two types of decoding, Manchester (phase encoding) and Biphase. The corresponding decoder can be selected by the pin MODE (0: Biphase, 1; Manchester).

To decode the "conditioned diphase encoding"(Differential Manchester Encoding), you will have to use the MLX90109 in direct mode with the pin MODE floating (internal decoder bypassed). Please not that the CLOCK pin will not be available in this mode.

Then the external micro controller needs to integrates the "DME" processing to be able to understand the information from the TAG.

Best Regards
Denis

Joined: 16 October 2008
Location: IT
Posts: 2

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Thank's a lot for the info and sorry for my English and if I have written in discourteous way I apologize me.
Good job and best Regards,
Paolo

Joined: 19 February 2009
Location: GB
Posts: 2

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Iam using an emx4000 series 125khz bead for our transponder. i have no info on the code transmitted from the bead to the mlx90109. dont know if anyone has this info. My question is this: if the bead code type is unknown, using manchester decoding could give the wrong data from the bead, as will biphasic mode. i understand i could decode it within the micro using no internal decoder but things could be simplified using the internal decoder. The code sent from our bead is not important as we are only detecting if a bead is present, and all beads are different anyway. how do we know which decoder to use?

many thanks
john oakley

Joined: 1 February 2006
Location: CH
Posts: 109

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Dear,

If the message send by the TAG is 2/4kbps encoded in Manchester/Biphase, it could be decoded using the internal decoder of the MLX90109. Anyway, if you want to use you it will have to know the type of encoding and the data rate.

It should also be better to know the header which starts the message, then you can easily decode the information and check the CRC is needed.

Best Regards
Denis