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ISO1410: No activity observed on A and B lines

Chan100
Genius 3040 points
Part Number: ISO1410

Hi everyone,

We are working with the ISO1410 half-duplex RS485/RS422 transceiver in our latest design. We are sending data on D line using a USB - UART interface module, when REb is low, DE is high. However we are unable to observe any data on the A and B lines. Following is the portion of schematic where we use the transceiver. R7, R9 and R10 are zero-ohm resistors while C14, C15 and C20 are DNMs.

Could someone suggest what can be going wrong here?

Thanks in advance,

-Chandrasekhar DVS

  • 0
    TI__Expert 6955 points

    Chandrasekhar DVS,

    I'm sorry you're having this issue. I think I see the problem though.

    The ISO1410 is a half duplex device in the ISO14xx family and the pinout is different on the bus side from the full duplex versions. I see you have the symbol for the full duplex devices in the schematic which means the bus lines aren't connected to the correct pins of the device.

    Respectfully,

    Lucas Schulte

  • 0 in reply to Lucas Schulte9
    Genius 3040 points

    Hi Lucas,

    Oh, I see now that the pin 14 was supposed to be NC and there was the mistake there in our schematic. Thanks for pointing that out!

    -Chandrasekhar DVS