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TLK2501: Initialization and Synchronization automatically

Robert Raum
Prodigy 30 points
Part Number: TLK2501

Hi,

I didn't get it properly from the data-sheet but hope to have found the solution to my problem:

I got 14 digital signals at 125MBit/s.
All the signals are a different source, not related to each other.

I want to transmit those 14 signals across an optical link and split them again to 14 parallel data-ports.
But I do not yet see how to initialize and synchronize the TLK2501.

The synchronisation between the two TLK2501 is happening by the comma-detection?
Is this happening automatically?
Or do I have to wait till the TLK2501s are synced and then switch ON my data-inputs?
Or do I have to provide the comma-patterns on the inputs?

I don't have a FPGA and don't have the option to generate any specific parallel pattern.

In another post I've read that only some of the pins need to be toggled.
Sadly I didn't get how that needs to be done.

If you could provide some information where I can get more details about that I`d be really glad.

Kind regards,

Robert

  • 0
    TI__Genius 10250 points
    Hello Robert,

    Yes; the sync is automatic (see section titled "synchronization and initialization") and uses comma pattern detection (see the section titled "comma detect and 8-bit/10-bit decoding"). The comma generation is handled by TLK2501 based on 2 input signals (pins): TX_EN and TX_ER (see the section titled "IDLE insertion") .

    Regards,
    Yaser
  • 0 in reply to Yaser Ibrahim
    Prodigy 30 points
    Hello Yaser,

    Thanks for your Reply, it was very helpful.
    By setting TX_EN and TX_ER I can Change the IC between sending comma-words and normal Operation.

    Can I use the RX_ER and RX_DV/LOS to toggle the TX-Pins between these states?
    From my understanding RX_DV/LOS connected to TX_EN and RX_ER connected to TX_ER should do it, or?



    Or is that not even necessary because according to figure 6 from datasheet also 1 set of valid data will establish the proper link.
    So if I set TX_EN = HIGH and TX_ER = LOW it should solve all issues?

    My biggest concern is a lost link during operation - due to I don't have any Option to Change TX_EN and TX_ER by any external intelligence.
    If I got the datasheet right the TLK2501 should go back to normal Operation automatically after a few clocks, right?
    If it is like that, that would be great!

    Kind regards,
    Robert
  • 0 in reply to Robert Raum
    TI__Genius 10250 points
    Hi Robert,

    You are right. And you actually don't need to connect TX_EN/TX_ER to RX_DV/RX_ER. You can think of it as if they are connected internally. Basically, you can tie TX_EN high and TX _ER low and upon power up/reset, the TLK2501 transmitter will keep sending IDLE until its receiver detects incoming IDLE or Valid Data.
    During normal operation, if an invalid code is received, the TLK2501 transitions to the CHECK state. In the CHECK state if it sees 4 consecutive Valid Data codes, it transitions back to the SYNC state for normal operation. However, while in the CHECK state, if it sees 3 invalid codes (do not have to be consecutive), it transitions to link acquisition state (ACQ). There it will transition to SYNC if it receives 1 valid data...

    Regards,
    Yaser