> On Wed, Jan 12, 2011 at 8:36 PM, Jamie Morken > <address@hidden> wrote: > > > > Hi, > > > > I am interested in helping out with making some new gnuradio > hardware that is compatible with the USRP daughterboards. I > worked with Matt doing CAD on the original gnuradio project > hardware and have since then made lots more boards including a > cyclone 3 board. > > > > Here is a possible hardware configuration: > > USB 3.0 transceiver IC or USB 3.0 microcontroller > > Altera Cyclone3 FPGA > > highspeed DAC/ADC > > > > If we use just a single channel ADC and DAC (ie half a USRP > v1) then we can get away with a smaller/cheaper FPGA and have a > cheaper/simpler board that can be paralleled if needed (ie. two > boards hooked up to USB 3.0) > > The idea of USB3 is nice for the future, but I don't think there are > enough peripherals out there yet to make a good board. I > can't really > find anything that's not completely preliminary and somewhat cheap. > I'd like to propose what I think may be a good compromise. > > Altera Cyclone IV EP4CGX15 FPGA, Analog Devices AD9861 MxFE, USB2 > microcontroller (for reprogramming the FPGA) in an ExpressCard/34 > format. The FPGA has a hard PCIe 1.1 x1 lane with a hard > IP core for > PCIe connectivity. The PCIe interface has an extremely low > latencyand pretty high throughput - ~200MB/sec full duplex > (after overhead > and whatnot). The FPGA would be mostly empty since the > PCIe core is > hard. If the F169 package is used, it should be compatible > with up to > a EP4CGX30 which would give 80 18x18 multipliers and over 1Mbit of > embedded memory. The ExpressCard format can fit into > desktop PC's > with simple and cheap adapters, or into laptops which have ExpressCard > slots. > > ExpressCard has both an x1 PCIe connection as well as a USB 2.0 > connection. I imagine a small USB 2.0 micro used for FPGA > configuration and, possibly, a secondary way for samples to enter/exit > the FPGA for different use cases (similar to the original > USRP). But > the main purpose would be for reconfiguration of the FPGA. > > Frequency synthesis can be an optional part of the > assembly. I > imagine a relatively inexpensive VCTCXO (2ppm accuracy?) along > with an > Si5338 clock synthesis chip. The idea, though, is to be > completelyoptional for those who really want it. > Otherwise, the FPGA PLL's can > probably be good enough for most people. > > For connectors, 2 HDMI (commodity and cheap, twisted pair, shielded > and rated to relatively high frequencies) - one for analog/baseband > signals, one for digital I2C/SPI comms. Goes to a daughterboard > carrier which can hold the daughterboard and a digital IO port > expander for controlling the RX/TX IO [0:15] pins for the db > connectors. > > I think the high bandwidth, low latency, and low CPU utilization of > PCIe is very attractive. The main downside to the parts > are the BGA > components which can be daunting for hobbyists, but toaster > ovens with > PID controllers can really do a pretty amazing job. I'm > not sure if > this is a dealbreaker or not. > > I'm very interested to hear other people's opinions as to proposed > interfaces, platforms, architectures, and connectivity. > > Jamie, I hope you don't see this as a hijacking of your original > e-mail. I am particularly interested in your response.
Hi Brian,
That sounds like a pretty good system. I should say right off the bat that if I am involved to make this I would want to add a clause in the open source hardware license to not allow the hardware to be used for military applications. I think it is important to state this at the start before I would get involved working on a new gnu radio board. If people can live with that requirement I am happy to do the layout work.