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ISO7741: SPI Data, the ADC data on the left side cannot be read

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Part Number: ISO7741


Iso7741 is used to isolate SPI data.
The left side of ISO7741 is a single-chip microcomputer and 1 ADC, and the right side of ISO7741 is 3 ADCs.
The single-chip microcomputer can only correctly read the data of the three ADCs on the right side, but the ADC data on the left side cannot be read. If iso7741 is removed, the ADC data on the left can be read correctly.

ADC-Analog Data Converter


Elsa Duan

  • Hi Elsa:

    Thanks for posting your question on E2E.

    If multiple slaves share the same SPI bus, slave devices’ SDO should go high impedance when chip select is high.

    In your application, please make sure that the EN1 pin of ISO7741 is driven low when the left side ADC is being read. This puts the OUTD of ISO7741 into high impedance allowing the SDO of the left side ADC to drive the SPI bus correctly.