Re: [Discuss-gnuradio] updated packet format on USRP inband signaling

[Eric Blossom]

On Sun, Feb 25, 2007 at 08:10:06PM -0500, Brian Padalino wrote:
> On 2/25/07, Eric Blossom <address@hidden> wrote:
> >On Sun, Feb 25, 2007 at 07:29:01PM -0500, Brian Padalino wrote:
> >> Some preliminary questions:
> >>
> >> How are the operations linked with the transmit sequences?
> >
> >I'm not sure I understand this question.
> 
> I am not sure how the operations being sent down are associated with a
> payload.  Are they just 32-bit aligned in either an in or out packet?
> If so, should there be something in the header to say how many
> operations are there before the actual modulated data starts?

If Chan == 0x1f the payload contains control operations, otherwise the
payload contains homogeneous samples (the type of which is specified
by the contents of some register(s) that were set earlier).

> >> Are operations sent down in bulk, or one at a time?
> >
> >You can send as many as will fit in the payload.
> >Unless you doing something like hopping, I suspect that command
> >packets are relatively infrequent.
> 
> It looks like the assumption I made just previously is accurate - the
> operations are in the payload along with modulation data.

No, they're distinct, based on the Chan field in the header.

My thinking behind this was to keep life simple for the common case:
If Chan != 0x1f, clock payload into appropriate signal processing pipeline.
If Chan == 0x1f, do the potentially slow, complicated work...

Eric