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Pin /RE and DE 是否有内部上拉电阻?

Thread Summary

The user inquires about the LTC2854 not functioning with R3 set to 10k ohms when switching between RS485 and SPI modes. The final answer suggests that the /RE and DE pins may have weak internal pull-ups, and decreasing R3's value to provide a stronger pull could resolve the issue.
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Category: Hardware
Product Number: LTC2854

Dear Expertise,

We use the above circuit for RS485 or SPI communication function, the signal 485/SPI_SW is used to select between 485 and SPI modes. We R3 is 10k, the LTC2854 does not work, but if R3=0, the circuit works properly. I wonder if the /RE and/or DE have internal pull-up resistors?

Many thanks for your kind attention and looking forward to your kind support.

Best wishes

Minym