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Precision Data Converters Forum
LMP90100 - Connecting 2 devices that are not isolated to the same SPI port
Can you recommend the best way to connect 2 LMP90100 devices to the same SPI port? There is an E2E post that involves doing this but the devices in that case are electrically isolated. The guidance offered there does not help in my case where isolation is not used. It seems some gating will be necessary to separate the DRDYB of each from the port SDO pin. A recommendation would be greatly appreciated.
Related, some SPI devices can operate in a cascade mode where SDO of device 1 can connect to SDI of device 2 and the devices act as one long data chain. This would be a very useful mode in my case but I do not believe this is supported by the LMP90100. Please confirm. A few more connection diagrams in the data sheet would be very helpful.
On running two LMP90100's from the same SPI bus, I believe you are referring to this post:
Not sure if you noticed but Asutosh and Javier had different issues (but both are in the same thread) - one was optically isolated and the other was not. If you read the parts of that post related to Javier, did Murali cover your question?
For connecting multiple LMP90100 to one SPI port of the MCU, there is no special programming needed for LMP90100. Care has to be taken to avoid asserting CSB's of both the LMP90100 together in the default condition. However there are various modes of the SDO driver which can be selected based on the application requirements.
Daisy chaining is not supported in LMP90100.
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