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LTC4331, remote I2C interface doesn't respond


I'm experimenting with the LTC4331 demo board, with my own uproc board. My setup is:

uproc <===> local LTC4331 <===> cable <===> remote LTC4331 <===> EEPROM

program is simple: continuously reading from (remote) EEPROM, filled with know data. So after each read do a compare, etc.

Initially I had spurious issues of stuck SCL, but found this article: Unexpected behavior of LTC4331 - Q&A - Interface and Isolation - EngineerZone (
After delaying each read with at least 35ms, as suggested in the article, all went fine.

Now next step I want to experiment with the control interface of the device. I can read the local I2C device (address 0x3E), but I get NAK's from the remote device. I tried every jumper setting for A1/A2, even made a quick scan routine to find all I2C devices. But all what is reported is 0x3E and 0x50 (for the remote EEPROM).

Q1: Is the remote I2C device suppose to respond on I2C register access?
Q2: Is the Packet Error Correction also applicable for the data transfer from my remote EEPROM to the local LTC4331? Or is PEC only used for transfers from uproc to the LTC4331 control interface?
Q3: related to Q2, if any bit error occurs in the transfer from reading my remote EEPROM to the local LTC4331, will that be detected as a 'fault'?


  • ... it's been awhile now since I posted my questions, but still no response. I'd like to get in contact with somebody from Analg Devices to discuss/ask a few topics on this device.


  • The control interface is intended for configuring and monitoring the i2C bus extension link and so treats the combination of the local and remote LTC4331 devices as a single logical device.  Therefore, the control interface is only accessible the local side bus.

    When enabled, the Packet Error Correction is only applied for data to/from control interface.  Other than the address translation for the remote side bus, the extension link is entirely transparent and just passes data through as is received.

    The LTC4331 link can detect some link errors (e.g. loss of communications or malformed data packets between the local & remote LTC4331s) and will report this as a fault; however, it is not performing error correction/detection on the I2C data being sent across the link.