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Original question:

TUSB1210: Implement KVM over fiber with TUSB1210

TUSB1210: USB J and K Chirp generation

Roland Feibert31
Intellectual 710 points
Part Number: TUSB1210

How does one generate the J and K Chirps with the TUSB1210? How does one generate chirps for LS/FS and specifically for HS mode.

Data sheet page 20 Table 5-10 indicates that the HS Transmitter is capable of generating the J and K Chirps.

The TUSB1210 DEBUG register 0x15 indicates when it sees a LS or FS J and K Chirp, but I do not see where it indicates that it sees a HS J or K Chirp.

I need to generate chirps for SYNC and EOP fields.

Thanks, Roland

  • 0
    Intellectual 710 points
    Is a KJ chirp different than a KJ pair?
  • 0 in reply to Roland Feibert31
    Intellectual 710 points
    It must be that the TUSB1210 generates the SYNC field and EOP field automatically when it generates the Link to PHY USB transaction.
    Thanks, Roland
  • 0
    TI__Guru**** 177676 points

    Roland

    Please see attached timing diagram for HS Chirp Sequence for host and peripheral.

    The following sequence of events must be followed.


    1. FS/LS Detect – The host detects a peripheral attachment as low speed if D- is high and as full speed if D+ is high. If a host detects a low speed peripheral, it does not follow the remainder of this protocol.


    2. Host Drives – If a host detects a full speed peripheral, it resets the peripheral by writing to the Function Control register and setting XcvrSelect = 00b (HS) and TermSelect = 0b which drives SE0 on the bus (D+ and D- connected to ground via 45Ω). The host also sets OpMode = 10b for correct chirp transmit and receive10. The start of SE0 is labelled T0. The peripheral PHY asserts dir and informs the Link of the LineState change using an RX CMD.


    3. Peripheral Responds – After detecting SE0 for no less than 2.5us, if the peripheral is Hi-Speed capable, the peripheral Link sets XcvrSelect to 00b (HS) and OpMode to 01b (chirp), and follows this immediately with a TX CMD (NOPID), transmitting a chirp K for no less than 1ms. and the chirp K must end it no more than 7ms after reset time T0. If the peripheral is in Low Power Mode, it must wake up its clock within 5.6ms, leaving 200us for the Link to start transmitting the chirp K, and 1.2ms for the chirp K to complete (worst case with 10% slow clock).


    4. Host Responds – If the host does not detect the peripheral chirp, it must continue the assertion of SE0 until the end of reset. If the host detects the peripheral chirp K for no less than 2.5us, then no more than 100us after the bus leaves the chirp K state, the host sends a TX CMD (NOPID) with an alternating sequence of chirp K’s and J’s. Each individual chirp K or J must last no less than 40us and no longer than 60us.


    5. HS Idle – The peripheral must detect a minimum of chirp K-J-K-J-K-J. Each individual chirp K and J must be detected for at least 2.5us. After seeing that minimum sequence, the peripheral Link sets TermSelect = 0b and OpMode = 00b. The peripheral is now in Hi-Speed mode and sees !squelch (01b) on LineState. When the peripheral sees squelch (10b) on LineState, it knows the host has completed chirp and waits for Hi-Speed USB traffic to begin. After transmitting the chirp sequence, the host changes OpMode to 00b and begins sending USB packets.

    Thanks

    David