What does RF 0/Rx/Enable and RF 0/TX/Enable stands for?

[Wired_]

I wanted to make sure what  RF 0/Rx/Enable and RF 0/TX/Enable stands for in  Streaming Xcvr (FPGA).vi example.

If  RF 0/Rx/Enable is made False for a particualr period of time in a different loop in vi diagram does that mean that USRP will not fetch any data for the while? And same shall go with transmission.

Will it close the session or just insure that data are not being fethched in  to RX/TX chain?

[brooksprumo · Accepted solution]

There are a set of registers for each daughterboard/RF group that are used for configuration, known as the ATR registers. There are four ATR registers that go through a mux, and then a single ATR register is chosen to apply configuration to the daughterboard/RF group. The ATR register mux is controlled by two bits. On daughterboard 0, it's RF 0/Rx Enable and RF 0/Tx Enable. On daughterboard 1 it's RF 1/Rx Enable and RF 1/Tx Enable. These two bits selects which of the four ATR registers is used to conifgure the daughterboard/RF group. This allows four separate configurations to be quickly toggled between.

The ATR registers configures items such as the daughterboard's power, the daughterboard's mixer enable, the antenna configuration (if the Tx/Rx antenna is switched to the Tx or Rx chain), among others. The four ATR registers get written with default values when the configuration VIs run from the host. The four ATR registers are commonly referred to as the following four states: Idle, Rx Only, Tx Only, and Full Duplex. Here's a table of how the ATR states are selected from the Enable bits:

Tx Enable | Rx Enable | ATR State

----------+-----------+----------

 F        | F         | Idle

 F        | T         | Rx Only

 T        | F         | Tx Only

 T        | T         | Full Duplex

So, to finally answer your question 🙂

The Enable bits control which ATR state is used to configure the daughterboard/RF group. The Enable bits do not controll if the USRP will or will not fetch data, per se, but the Enable bits may select an ATR state where the daughterboard's power is turned off or the daughterboard's mixer is turned off.

The ATR registers and the ATR states are mostly only needed for advanced applications requiring non-default configuration and/or the need to rapidly toggle daughterboard/RF group configuration.

I hope this helps!

[Wired_]

Thanks a lot for detailed reply.

As far as my aim is concerned I want to toggle between receiver and transmitter mode hence wanted to temporarily avoid receiving any samples I am transmitting and vice versa. I hope, as suggested by other in the group too, toggling these values should solve the issue.

[sumitstop1]

Hello, 

So in order to do half-duplex, I have to toggle between the following two states 

 F        | T         | Rx Only

 T        | F         | Tx Only

Or is there any other trick for that 🙂 

Regards

Sumit