Thanks Peter, Yeah DMA mode was no go for us at this speed. That really did just create spurious data.
FIFO mode with hardware flow control seems to be stable right now. Thanks for coming back to me! Lee On Fri, Dec 11, 2015 at 7:12 PM Peter Hurley <[email protected]> wrote: > Hi Lee, > > On 12/11/2015 11:01 AM, Lee Armstrong wrote: > > Hi Peter, > > > > It is on the RX side of things into the BBB and I am seeing the RTS > > signal goign across to our hardware. I think the threshold is 48 out > > of the 64 buffer from looking at and experimenting. > > > > 3Mbps is the baud rate and yes we were seeing an overrun and then > > corruption of the FIFO. RTS seems to be working now that we have > > worked it out that the throttling happens at 48.> > > Lee > > There are some issues at 3Mbaud, most likely related to dma. > Could be silicon. See here: > > https://lkml.org/lkml/2015/12/3/442 > > > > On Fri, Dec 11, 2015 at 6:59 PM Peter Hurley <[email protected] > <mailto:[email protected]>> wrote: > > > > On 12/11/2015 09:20 AM, Lee Armstrong wrote: > > > Anyone know what the RTS/CTS thresholds are for the 8250_omap > driver > > > that I am pretty sure the BBB uses by default? > > > > > > I can't work it out! I know that the signalling of RTS is working > as > > > I see it go high on the scope but I need to know how many bytes it > is > > > safe to send before an overrun happens again! > > > > The serial core + 8250_omap driver automatically prevent tx fifo > > overflow; you don't have to worry about overrunning the fifo when > > writing. > > > > Are you observing overruns at the receiver with CRTSCTS on? > > Is there a message or are you observing data corruption? > > Is the receiver also a BBB or something else? > > What baud rate are you using? > > > > Regards, > > Peter Hurley > > > > > On Thursday, December 10, 2015 at 7:07:10 PM UTC, Lee Armstrong > > > wrote: > > > > > > Thanks Robert. > > > > > > 64 for the FIFO is what I suspected but couldn't see the CTS > > > threshold. Was that 48? > > > > > > Also these look pretty hard coded into the kernel. Anyone know a > way > > > of setting these after a compilation or how to compile in with > other > > > values? > > > > > > Lee > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/xzxFvnIg_Uc/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
