T/R switching, like transmit receive switching for a TDD use case? This is something we are going to need FPGA control over because this needs to be automatic. Typically for this sort of use case I would design a set of registers in the FPGA that drive the frontend switch IOs based on a Tx condition.
- Theres two registers,
- one that represents the IO state when transmitting,
- and one that represents the IO state when transmitting is off (receiving).
- The FPGA uses the the transmit state (driven by tx fifo activity) to switch between these registers
- Then the driver needs to setup these registers in advance given some configuration by the user.
From the software side, this register configuration is usually based on an antenna selection. But in the case of the limsdr, there is no frontend switching, so there isnt yet a way to convey this software wise. But with some fpga support and target use case, I’m sure we can imagine a special antenna selection that engages this configuration.