
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