On Fri, Jun 12, 2020, 5:18 PM Gregory Nutt <spudan...@gmail.com> wrote:
> Hi, again, > > I suppose the first question should be, "Is the FT245RL the correct > choice?" After all, it is only 8-bits wide and only USB 2.0. That could > limit the amount of instrumentation data passed to the host because of data > overrun or or it could alter the real-time behavior of the target. > Ideally, the instrumentation should involve minimal overhead and the > behavior the real time system should be the same with or without the > instrumentation enabled. Otherwise, such a tool would not be a proper > diagnostic tool. > > I considered some PCIe parallel data acquisition devices, but did not see > a good match. PCIe would be hot, howeer. > > I also looked at FTDI FT60xx devices, but these seem so camera focused > that it was not completely clear to me that these could be usable. But I > am a mostly a software guy. Perhaps someone out there with better > knowledge of these devices could help out. > > The older FT600x, for example, has a 16-bits wide FIFO (pretty much > optimal for most MCUs) and has a USB 3.0 interface to the host PC. Using > such a camera-oriented device is less obvious to me than the more general > FT245RL. Perhaps that is only because of the camera-oriented language used > in the data sheets? > > If you know something about these options, I would like to hear from you. > > Greg > If you want high-speed io to USB the FX3 is probably one of the best bets. You see it frequently used on logic analyser and software defined radio boards between the USB and the FPGA. https://www.cypress.com/products/ez-usb-fx3-superspeed-usb-30-peripheral-controller Somewhat related but have in the past modified the firmware on this for some custom debugging. https://1bitsquared.com/products/black-magic-probe --Brennan >
