I tried doing the matching XIN/XOUT. At first I assumed the matching pairs were actually not required, but I tried it both ways when it did not work. I'm using interrupts between the PRU's to let the other know when data is available to read, so it's possible that the timing on these interrupts is making it take longer than 1024 clocks before I get to read.
FWIW, using the PRU's to do 2D line drawing basically out to DAC's. PRU1 will be using Bresenham's line drawing algorithm (no div/multiply required: http://en.wikipedia.org/wiki/Bresenham's_line_algorithm) between values read from DDR RAM while PRU0 will be bit banging SPI out to the two DAC's. This should keep both of the PRU's busy and streamline the process a bit. Thanks again for the help. -Kent On Wednesday, October 9, 2013 9:58:14 PM UTC-5, Charles Steinkuehler wrote: > > On 10/9/2013 9:39 PM, Kent Bowling wrote: > > I see in your code you're using scratch pad 0 (the 10 in your > > instructions). I'm trying to use the direct PRU to PRU version (14) and > > it's not working for me. I just tried your approach (pad 0, AKA 10) and > it > > works fine. > > > > Am I wrong in thinking you could use 14 and copy registers directly > between > > the PRU's? > > I haven't tried doing direct PRU to PRU transfers. Note that it isn't > really in bold print in the documentation, but are you doing an XIN on > one PRU and an XOUT on the other? > > If I'm reading things correctly (section 5.2.4.2, top of page 35 in > SPRUHF8A) the first PRU will stall until the other PRU performs the > matching XIN/XOUT instruction, or 1024 clocks go by. So if you're > getting pr1_xfr_timeout events (you should be able to check for this in > the status bits of the INTC, it's interrupt number 3), you're getting > timeouts from not having a "matched set" of XIN/XOUT pairs. > > -- > Charles Steinkuehler > [email protected] <javascript:> > -- 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/groups/opt_out.
