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LM3549: EEPROM Calibration data format

TonyMakkiel
Expert 1180 points
Part Number: LM3549

Hi,

Can somebody confirm the format of the data read from internal EEPROM please?

If we were to write the calibration data onto the EEPROM, can the register number be used as offset within the eeprom (For Example 4th byte in the EEPROM is IG0_MSB)? What about the 17th byte (fault register)? Is that left empty within the EEPROM or does it take USR1?

Cheers,

Tony

  • 0
    TI__Intellectual 2090 points
    Hi Tony,

    I am looking into this and should be able to get back to you in 2 days.
    Let me know if you need an answer sooner.

    Best regards,
    Randy
  • 0 in reply to Randy Dahl
    Expert 1180 points

    Thank you Randy. Within 2 days would be fine.

  • 0 in reply to TonyMakkiel
    TI__Intellectual 2090 points
    Hi Tony

    The current value in the I2C register is written to EEPROM during EEPROM programming.
    Page 10 of the datasheet outlines the sequence for EEPROM Programming.
    Let me know if you need additional detail.

    Best regards,
    Randy
  • 0 in reply to Randy Dahl
    Expert 1180 points

    Hi Randy,

              Although it says how to write to the EEPROM, it does not say, what to write or the format of data to be written. Normally I would guess 1st byte in the EEPROM represents settings of Register 0. Is it correct?

  • 0 in reply to TonyMakkiel
    TI__Intellectual 2090 points

    Hi Tony,

    The value in the I2C register is written to EEPROM, the external controller does not need to know any special format or address of the EEPROM.  The eeprom data and address is mapped from/to the I2C register internal to the LM3549.

    For example if you need to change IB1_LSB (I2C Addr 0x0B) from default value of 0xE7 to a new value of 0xE2 you only need to perform I2C write to Addr 0x0B with Data 0xE2, then follow the EEPROM programming sequence.  The new value 0xE2 will be programmed to EEPROM at the correct eeprom address.  The new value will be transferred to the I2C register when the LM3549 goes through STARTUP mode of operation.  All I2C registers mapped to EEPROM are written during the EEPROM programming sequence (refer to Register Map table on page 15 and 16, NOTE column).

    I hope that his helps, let me know if it is still not clear.


    Best regards,

    Randy

  • 0 in reply to Randy Dahl
    Expert 1180 points
    Thank you Randy. I got confused. I was under the impression the EEPROM needs to be written from the host.