Other Parts Discussed in Thread: SN74LVC1G125
I am developing a PCBA which uses this part. It connects between a TFB4711 and a ATSAMA5D27C CPU. All the UART ports are used up on the CPU, so I want to share the TIR1000 with the CPU's debug UART port. The debug UART port is connect connected to anything else except a test jig for R & D purposes. So it makes sense to utilise this port for the IR work in the product.
So the question is: Are the U-TXD and U-RXD lines tristated when the chip is held in reset? That is I want the debug port to be usable when this chip is present.
I have placed zero ohm resistors to isolate this UART from the TIR1000 if required as a mechanical workaround. I can even use a tri-state buffer chip, but I want to keep parts count to a minimum and real estate is very tight. No point using a tristate buffer when we don't need one. The datasheet does state how these pins behave with RESET, other than the state machine in the chip is reset.