On Thu, Feb 16, 2012 at 5:15 PM, Dave Tweed wrote: > Vasile Surducan wrote: >> On Thu, Feb 16, 2012 at 2:50 PM, =A0 wrote: >> > > > Hi all, >> > > > >> > > > I need to interface an 120Msps serial ADC with LVDS output to an U= SB >> > > > 2.0. Does anyone knows a small ASIC, DSP or whatever which allows = this >> > > > simple task. I thought also to USB to SATA bridge, however I need = a >> > > > few programmable IOs for controlling the A2D, >> > > >> > > Classic application for a small FPGA, plus FTDI FTx232H hi-speed USB >> > > interface. FPGA will handle LVDS conversion, some RAM for buffering = and >> > > handshaking. >> > >> > When you say LVDS, what format is it? Does it work just like an SPI de= vice >> > (LVDS really is only the differential hardware layer). If it does work >> > like an SPI device then a Microchip 2210 USB-SPI with an LVDS driver a= nd >> > receiver chip may do what you want. >> >> It's 14 bit serial output in one lane (one bit a time) or two lane >> (two bits at a time) and frame, all LVDS output. >> Also has a SPI for commands. See for example LTC2268. > > Clearly, this is anything but a "simple task". Given that high-speed USB = can > only support about 40 MBps sustained, you'd only be able to operate this = chip > at 20 Msps or so with a "bare-bones" interface. If you want to burst data= at > higher sample rates, you're going to need a significant amount of high-sp= eed > buffer memory between the ADC and the USB. > > Just as an example, look at Linear's DC1371A board, which performs the > function you are asking for. It includes a rather hefty Virtex-5 FPGA alo= ng > with a couple of high-speed ZBT SRAMs. Granted, this board supports many = more > features than you probably need, but the basic data handling is going to = be > very similar. > > You're going to have to give us a better idea of what you're trying to do= with > this chip before we can offer meaningful suggestions. BTW, this is exactl= y the > sort of FPGA design work that I do. If you'd like to discuss this project > off-list, send a message to dtweed at dtweed dot com. Thx Dave, I know quite well Virtex5, I've designed one project with, but now is not applicable because of space and power constraint. In fact Virtex5 is good only if an ASIC is finally implemented, which is not the case. I think the price of Virtex5 does not recommend it for such application. So, USB2.0 can only 40Mbps? Vasile --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .