[Discuss-gnuradio] USB packet format / inband signaling

[Thibaud Hottelier]

Hi all,

First of all, I would like to make sure that I have understood what is
going to be modified. I have made a diagram with the whole Gnuradio
component stack: http://img168.imageshack.us/img168/415/groveralleb2.png

1) The new usb packet will be encoded/decoded in the gnuradio uspr
driver and in the FX2 firmare right?

2) The FX2 and the fpga communicate using the serial bus (SDI/SDO) (plus
some control signal like usb_ctl, usb_rdy) and the usb_data bus. Will
the commands be sent trough the serial bus or through the usb_data bus ?

What is exactly the daughter board role and its responsibilities ? Is it
only a physical interface for the antenna ?

I also a few question about the format itself:

I don't understand the purpose of the Tag field. Can you explain it a
little bit ?

I don't understand how the timestamps will work on OUT packets: How the
host will know what the value of the 32 bits counter incremented by the
A/D sample clock ? Is the timestamps the absolute value of the clock or
a delta?

SPI is used to write to the AD9862 register but what is I2C ?

Thanks,
Thibaud