Re: [Discuss-gnuradio] Questions about RAW ethernet driver, UHD and firmware

[Marcus D. Leech]

On 04/07/2011 1:52 PM, Nemanja Trecakov wrote:

Hi list,

 

My name is Nemanja and I am working on my master theisis using USRP2 with XCVR2450, using Ubuntu 10.04 and gnuradio 3.3.0. However, I am new to GNU radio and I need help to understand some basic things in order to continue. I tried the gnuradio-wiki, mailing lists and google with no success. I would be very thankful if somebody could enlighten me.

 

1)      I want to implement some extra things in FPGA, by adding some extra features with Xilinx ISE 12.4 in the current FPGA image.

However, on the link: http://code.ettus.com/redmine/ettus/projects/public/wiki/U2binaries,

Raw Ethernet Driver and Universal Hardware Driver are mentioned. I have read that UHD is the recommended one.

- WHAT IS THE DIFFERENCE between these two, WHAT ARE THEY USED FOR and HOW CAN ONE USE THEM?

The "RAW" drivers for USRP2-family devices (including N200 and N210) are basically deprecated.  I'd start down the path of going
  "UHD".

Here's the starting point for UHD:

http://code.ettus.com/redmine/ettus/projects/uhd/wiki

If you're starting from nothing, there's the "build-gnuradio" script which downloads the latest source code for Gnu Radio, UHD, and
  installs all the prerequisites, it also downloads the pre-built firmware and FPGA images.

http://www.sbrac.org/files/build-gnuradio

 

2 )  On the link: http://gnuradio.org/redmine/projects/gnuradio/wiki/USRP2GenFAQ

there is a small list of some important trunk USRP2 code which is recommended for reading in order to understand USRP2 architecture, configuration and operation.
Quote: “In the FPGA code, the tx_control.v and rx_control.v show inband signalling, dsp_core_rx and dsp_core_tx show the DSP, and u2_core.v is the top level.

In the firmware, start with txrx.c.”

-         WHERE CAN I FIND THESE FILES?

The UHD source-code tree includes the Verilog for the FPGA, and the C code for the firmware for the ZPU.

-         WHAT IS AND WHAT DOES THE FIRMWARE DO, IN THIS CASE?

-         ISN’T THE FIRMWARE “GLUED” TOGETHER WITH FPGA IMAGE IN THE SD CARD ON SOME WAY?

 

The SD card contains two distinct images that are loaded into memory--the FPGA image, and the firmware image.

The FPGA contains a "Soft CPU" (used to be an aeMB, but is now a ZPU).

This "Soft CPU" runs firmware that manages a lot of the low-bandwidth configuration "stuff" related to the hardware, while the
  rest of the FPGA handles DSP operations, and actual high-speed "data pumping" from/to the DSP and Ethernet.

If you run the "build-gnuradio" script described above, you'll have source code for both UHD and Gnu Radio, and in UHD, there'll be both
  "fpga" and "firmware" sub-directories.