On Fri, 2009-06-26 at 17:04 -0700, David Brownell wrote: > On Friday 26 June 2009, Zach Welch wrote: > > Any tips for handling N RTCK signals, other > > than my brute force "use part(s) of a 7400 series IC" or plain "simply > > don't" approaches? > > I found some info in a TI presentation when I was > searching for 1149.7 or maybe ICEpick information ... > ICEPick has some RTCK smarts, and TI has some VHDL > they'll send you. Apply Google... > > Basically, you want want RTCK(out) to be high only > once *all* RTCK(i) input values are high. And then > you want it to go low as soon as *any* RTCK(i) input > goes low. I think there was some other nuance too; > the VHDL probably captures some timing constraints, > like minimum high and low times. > > The "combine N RTCK signals" issue comes up both > at chip and board level integration. With a JRC, > you've also got to gate each RTCK so that it's not > included in the RTCK(out) computation unless it's > actually part of the scan chain.
Thanks for this great explanation. Would you mind retouching the RTCK FAQ in the The User's Guide? There is already a little information there (which was not as immediately helpful as I needed it to be), and some of the details you provided here might supplement it nicely. > p.s. Yes, most targets should "just work". Cool. I need to do something like this to remind myself that it's possible to have some fun with these tools. :/ Cheers, Zach _______________________________________________ Openocd-development mailing list Openocd-development@lists.berlios.de https://lists.berlios.de/mailman/listinfo/openocd-development
