Re: [Discuss-gnuradio] FX2 Controller/ GPIF questions

[Thomas Tsou]

On Wed, Feb 16, 2011 at 3:54 AM, Arya Santini <address@hidden> wrote:
> Hi All,
>
> Can anyone shed some light on how the FX2 firmware / GPIF handles
> simultaneous reads and writes? I mean if I set up my USRP1 to receive
> and transmit simultaneously, what is happening exactly down there at
> the GPIF level? Given that there are two GPIF waveform configurations
> one each for Read and Write, are there two concurrent instantiations
> of the FIFO state machine during simultaneous read/ writes for full
> duplex operation , or in other words are there separate FIFO state
> machines operating in two configurations at the same time? If the GPIF
> state machine is in only one configuration (FIFOWr or FIFORd) at one
> time, how is true full duplex communication possible?

There are separate GPIF waveforms for reads and writes, which occur as
512 byte bursts when data and buffer space are available. FIFO buffers
in both directions allow for full duplex operation.

There's a good summary of the main run loop on the wiki page.

http://gnuradio.org/redmine/wiki/1/UsrpFAQFX2

  Thomas