I notice in table 10 of the datasheet that bits 2 and 1 of register address 0x0F allow "transmitter disable" and "receiver disable", can I verify the expected operation of these lines when disabled?
I was hoping that the TX and RX lines would be undriven and remain high impedance or at 0V. In practice we're finding that the TX line is continuing to idle high (3.3V in our case). We're changing these bits in the register and are reading the register back correctly, confirming that the RX and TX disable bits have been changed from 0 to 1. We do not have other devices or pull-up resistors connected to the line.