On Jul 26, 2012, at 12:24 PM, Mike Frysinger wrote: > On Wednesday 06 June 2012 22:09:01 eldentyrell wrote: >> The "pod" command lets the user directly modify the TCK, TMS, and TDI >> pins. However, it does not appear that there is a complementary command >> to directly read the TDO pin without doing any shifting. >> >> Below is a patch against SVN 2026 that adds this command. > > i'd just integrate it into the existing pod command rather than add a > dedicated one.
Sounds good to me. Do you need me to resubmit the patch to make it part of the "pod" command or will you do that? >> This is useful with devices that bend the rules of the JTAG protocol -- >> for example Xilinx FPGAs sometimes act as if they have an "infinitely >> large" DR register for loading bitstreams. > > i'm not sure how this is relevant. as long as TMS doesn't change, you can > shift in bits into DR forever. I don't think it can be done with the existing set of urjtag commands (and without creating an SVF file and then loading that), but if you know how I'd like to hear about it! Apparently the only way to access TDO from the command line in urjtag is to tell it the size of the DR and then tell it to shift the DR. However, when loading a bitsream, there really isn't a "DR shift register length" -- no matter how many bits you push in one end you'll never see those same bits come out the other end. So no finite number would be a correct answer. It's a "bottomless shift register" in that sense. Anyways, it's tangential. The important part is the TDO command so I can communicate with BSCAN_SPARTAN6 directly. Thanks! - e ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ UrJTAG-development mailing list UrJTAG-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/urjtag-development
