Re: [Discuss-gnuradio] digital noise input

[Eric Blossom]

On Fri, Nov 10, 2006 at 07:23:07PM -0800, Oussama Sekkat wrote:
> On 11/10/06, Eric Blossom <address@hidden> wrote:
> 
> Yes, I could enable the output pins from the host and just connect the
> rx_a_a to one of the debug inputs in the master_control module. I thaught it
> wouldn't make a difference if I just connect it directly to the DEBUG pins.
> Or does it?

It depends on whether or not you need to be able to control the
attached daughterboard too.

> >I then load the .rbf file to the FPGA, connect the io_rx_a outputs of the
> >> LFRX daughter board to the logic analyzer and observe what I get. I make
> >> sure that no antenna is connected to the RX-A port.
> >> To my surprise, some of the upper bits toggle. For example, bit 11, 10,
> >9,
> >> 8, 5 ,4 , 3 ,2 ,1 0, toggle. Since I should only be getting noise, I was
> >> expecting to get a very low signal where only the least significant bit
> >> would be switiching between low and high values.
> >
> >Are they being driven or are they just floating?
> 
> No antenna is connected to the RX-A and RX-B ports , so those are floating.


> But the debug pins are connected to the logic analyzer. (I am not sure if I
> answered you're question, when you say "they" are you referring to the DEBUG
> pins or the input ports? )

No, not the antenna, the i/o pins.  My guess is that you haven't
output enabled them.

Eric