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DS100KR401 pin mode

Casey Morrison
Intellectual 1985 points
Other Parts Discussed in Thread: DS100KR401, DS100DF410, DS100KR800

This question was paraphrased and posted on behalf of another user.

Question: Can the DS100KR401 work in a stand-alone application, without an SMBus connection?

Casey Morrison

  • 0
    TI__Intellectual 1985 points

    Answer: Yes, the DS100KR401 can operate in either "Pin Control Mode" (ENSMB=0), "SMBus Slave Mode" (ENSMB=1), or "SMBus Master Mode" (ENSMB=float).

    Control Mode ENSMB pin Description
    Pin Control Mode 1K-Ohm to GND Settings like RX EQ, TX VOD, TX de-emphasis, MODE, and signal detect threshold are controlled via pin settings. Refer to the Pin Descriptions and Functional Descriptions section of the datasheet.
    SMBus Slave Mode 1K-Ohm to VDD Settings like RX EQ, TX VOD, TX de-emphasis, MODE, and signal detect threshold are controlled via SMBus registers. Refer to the Pin Descriptions and Functional Descriptions section of the datasheet.
    SMBus Master Mode Float Settings like RX EQ, TX VOD, TX de-emphasis, MODE, and signal detect threshold (and others) are auto-loaded from an external EEPROM on power-up. Refer to the SMBUS MAster Mode section of the datasheet. After the auto-load from EEPROM is complete, the device reverts to SMBus Slave Mode, and settings can further be altered by the SMBus master.

    Note that SMBus mode allows for more flexibility and quicker turn-around for testing with different settings, which can especially be helpful during system bring-up and testing, when different TX and RX settings are often tested.

    Regards,

    Casey

  • 0 in reply to Casey Morrison
    TI__Prodigy 90 points

    Thank you. Two follow-on questions:

    #1: Would the DS100DF410 behave in the same manner- by simply floating EN_SMB pin and DS100DF410 will run in stand-alone-mode via the EEPROM?

    #2: On the eval board design, I was wondering if there are any issues with using the following EEPROMs that we have our company's AVL?

    • Atmel Corporation         AT24C02C-SSHM-T         A
    • Microchip Technology Inc.          24LC02BT-I/SN  A
    • SGS-Thomson Microelectronic M24C02-WMN6TP          A
  • 0 in reply to Tom Shyp
    TI__Intellectual 1985 points

    Hi Tom,

    The DS10DF410 will automatically read its configuration from an EEPROM if you float the EN_SMB pin (#20) and assert the READ_EN# pin low (#44). For more details, please refer to the "SMBus Master Mode and SMBus Slave Mode" section in the datasheet.

    Manufacturer

    		 Part number Size Supported for DS100DF410 and DS100KR4011

    Atmel corporation

    		 AT24C02C-SSHM-T 2Kbit

    Yes
    Microchip Technology Inc. 24LC02BT-VSN 2Kbit Yes
    SGS-Thomson Microelectronic M24C02-WMN6TP 2Kbit Yes

    1Note the DS100DF410 and DS100KR401 cannot share the same EEPROM. One or more DS100DF410 Retimers can share one EEPROM, and one or more DS100KR401s can share one EEPROM.

    Please also refer to this E2E post concerning the appropriate EEPROM size: http://e2e.ti.com/support/interface/high_speed_interface/f/138/p/282676/985639.aspx#985639

    Regards,

    Casey

  • 0 in reply to Casey Morrison
    TI__Prodigy 90 points

    One more question:

    Do you see any problems with inverting the polarity into a single side of one channel?  My understanding is that each TX or RX has an independent polarity inversion bit, so this shouldn’t be a problem, just need to properly set it in the EEPROM file. Is this correct? Any concerns in doing this?

    Thanks.

                           

  • 0 in reply to Tom Shyp
    TI__Intellectual 1985 points

    Hi Tom,

    If you are talking about the DS100DF410, then each channel has a polarity inversion bit. This means that for each of the four channels the input-to-output polarity can be true (non-inverted) or inverted. The devices on either side of the DS100DF410 (ASICs, FPGAs, etc.) often have their own polarity inversion capabilities, so the problem of inverted polarity on a board design can be solved in multiple places.

    If you are talking about the DS100KR800, then there is no polarity inversion capability. 

    Regards,

    Casey