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LTC2974 Automatic detection

Hello.I have a question. please tell me.

The designed board is equipped with an LTC2974.

I will write to the LTC2974 via DC1613A.

Also, 5V is applied to Vpwr, and VDD33=3.3V and VDD25=2.5V can be confirmed.

However, when I connect the DC1613A to the board with power on and start "LTpower Play", the LTC2974 is not detected.

This will not occur if "MFR_SPECIAL_ID" is 0x0215.

It seems to occur only when "MFR_SPECIAL_ID" is 0x210.

When I run a product with MFR_SPECIAL_ID of 0x210 with the latest LTpowerplay Is it compatible?

(Looking at the LTC2974 datasheet, the "MFR_SPECIAL_ID" can be 0x0212, 0x0213, etc., depending on the revision.)

If possible, what is the cause and how can it be remedied?

Best Regards.

  • Hi Baggio

    The first ID we released was 0x212.  We never released ID=0x210.  I guess it's possible that 0x210 was an early sample but this is officially an unsupported chip.  However the LTpp software does not perform an exact match on every ID, but rather it masks the lower nibble.  It looks for 0x021x.

    Are you selecting the Detect Chips button when the GUI starts up?  Are you clicking the Enumerate I2C Bus icon in the toolbar?  You should be able to open a .proj file with the 2974 and Go Online, and the GUI will be able to communicate with the chip.  Assuming the proj file has an address that matches the hardware.

    Mike 

  • Hi mpeters-san

    Thank you for your response.I understood that there is no ID = 0x210.

    We will answer the questions you have received.

    ・Are you selecting the Detect Chips button when the GUI starts up? 

     →Yes

    ・Are you clicking the Enumerate I2C Bus icon in the toolbar?

     →Yes

    ・You should be able to open a .proj file with the 2974 and Go Online, and the GUI will be able to communicate with the chip. Assuming the proj file has an address that matches the hardware.

     →Does this mean "MFR_I2C_BASE_ADDRESS_LTC"?

      If it is ”MFR_SPECIAL_ID_LTC", you can see 0x210.

      Also, during this operation, communication is not stable and connections and disconnections are repeated.

      (Only those with MFR_SPECIAL_ID_LTC of 0x210. What is displayed as 0x215 is working fine.)

    Best Regards.

  • Hi baggio,

    If you haven't programmed or written any registers, then MFR_I2C_BASE_ADDRESS is 0x5C. And check the ASEL1 and ASEL0 pins, this determines the offset.  The master (LTpowerplay) will see the chip at the address defined by the BASE_ADDR + offset.  The proj file should use the same address.  This is the manual method.

    I don't think LTpp ignores 0x210 and responds to 0x215.  Can you use a scope or bus snooper, and view the traffic?  A scope with built-in I2C decoding is very useful for this.

    Mike

    edit: I looked at the i2c traffic when LTpp starts up, and it goes thru all the addresses from 0xD to 0x7F to see which addresses ACK. Then it sends a read of the OPERATION register, and a read of the MFR_SPECIAL_ID later but this doesn't tell me if it uses this to populate the system tree.  If you have a chip with an ID of 0x210, does it respond to 0x1 (OPERATION)?

  • Hi mpeters-san

    Thank you for your response.

    It seems that the chip with ID 0x210 is also written correctly by executing the following.

    -Checked by default in LpowerPlay Preferences Implemented changes such as removing all items

    So I think 0x1 (OPERATION) is working well.

    However, I found that ID=0x210 has not been officially released, so I will consider replacing the part and comparing the waveform with an oscilloscope.

    Thank you for your support.

  • Hello mpeters
    My name is Itoyan.
    I got ID = 0x210 and contacted the agency.

    It is said that ID = 0x210 is not an officially released product and may be an early sample, but could you please tell us about the risks of using ID = 0x210 as far as possible from the following viewpoints?
    A. Function: Is there a difference in function from the officially released product?
    B. Electrical characteristics: Is there a difference between the officially released product and the electrical characteristics?
    C. Inspection process, inspection criteria: Is the inspection different from the officially released product?
    D. Operating environment conditions: Is there a difference between the officially released product and the operating temperature range?
    E. Reliability: Is there any difference from the officially released product?
    It may be difficult to answer questions that are not officially released, but as reference information, some of them are fine, so it would be helpful if you could answer.

  • Hi ltoyan,

    The LTC2974 did not significantly change functions or features from the early samples to the latest rev. which is ID=0x215.  We have a document that details changes to the part.  The most significant change was the addition of ECC to the EEPROM.

    https://www.analog.com/media/en/PCN/ADI_PCN_19_0118_Rev_-_Form.pdf

    Mike