> Thanks for the responses! > > Is there a convenient way to get around the unidirectional IO restriction > on ROACH?
Not as far as I know. It's possible to do it, just no support in the libraries. It would be nice if someone could write a bidirectional yellow block. We started on it, but we got distracted and didn't get back to it. :) John > > -Alex > > On Fri, Mar 8, 2013 at 1:27 AM, Andrea Mattana <matt...@ira.inaf.it> > wrote: > >> We have used at least as output signals where we have connected >> additional LED, but never used as input trigger. >> >> Andrea >> >> >> 2013/3/8 John Ford <jf...@nrao.edu>: >> >> Does anyone have any input on trying to use the GPIO A and B headers >> for >> >> very simple inter-ROACH direct FPGA to FPGA communication? I'm know >> that >> >> ROACH supports this sort of thing using 10 gbe, but for conveying >> trigger >> >> pulses, this (to my rather casper-naive intuition) seems simpler and >> >> cheaper, with lower latency. >> > >> > The design for the GBT VEGAS machine uses this sort of communication >> for >> > synchronizing the roach boards to a telescope switching signal. we >> > designated one as the master and propagate the signals over the GPIO >> pins >> > to the slaves. Seems to work for us. >> > >> > You can use the gpio yellow blocks for the interface, as long as you >> don't >> > need a bidirectional pin. >> > >> > John >> > >> > >> >> >> >> Any thoughts? >> >> >> >> -Alex >> >> >> > >> > >> >
