**** BEGIN LOGGING AT Sun Jan 14 02:59:58 2007 Jan 14 16:45:19 I am interested in hooking up a jtag to my nslu2 (slug), and have read the info in pinouts from nslu2-linux.org, but am still a bit confused if I need to also hook up TRSTn and RESET_IN_N signals Jan 14 16:46:12 Also can I just use an unbuffered cable from parallel port or do I have to build a buffered cable ? Jan 14 17:14:14 alorenz: do you want to use the jtag just for flashing, or do you want to be able to debug the ixp? Jan 14 17:15:14 alorenz: you'll certainly need buffers to account for the 3.3V of the slug vs 5V of the parport Jan 14 17:19:17 What I want to do is increase the memory size, for that according to the documentation I will need to install a different bootload (apex), and again according to the documenation I really need to have a reliable jtag to recover from problems Jan 14 17:20:04 alorenz: you'll only need to be able to flash then Jan 14 17:20:33 alorenz: that means you should be able to do without RESET_IN_N, and probably even without TRSTn Jan 14 17:21:43 what do the TRSTn and RESET_IN_N pins do ? I was not able to understand from the documentation Jan 14 17:22:31 TRSTn is used to reset the JTAG TAP (test access port), possibly including debug logic (but that depends on the target) Jan 14 17:22:38 RESET_IN_N resets the target processor Jan 14 17:23:04 as the nslu2 uses an XScale processor, you need both reset lines if you want to be able to debug Jan 14 17:23:32 flashing uses the jtag interface to get access to all the device pins Jan 14 17:23:40 you don't need the reset signals for that Jan 14 17:27:56 I have been reading on jtag at wiki.openwrt.org where they just hook up the 4 signal through 100 ohm resistor, is this enough to drop the voltage or should I really build the WIggler type ? Jan 14 17:28:41 which has a buffer the link is http://wiki.openwrt.org/OpenWrtDocs/Customizing/Hardware/JTAG_Cable Jan 14 17:33:48 sorry, not sure - I personally wouldn't use an unbuffered cable, but it might work just fine Jan 14 17:38:15 http://www.whipy.demon.co.uk/wiggler.pdf although not showing pinout for a parallel port it supports 3.3 or 5v host and 1.2v to 5v jtag Jan 14 17:40:20 Thanks. Will probably make the buffered cable. .. Jan 14 17:42:21 needs to be a 74hc05 or 74ac05 if the host is 3.3v Jan 14 17:43:01 alot of the wigglers i have seen use 74hc244's they still give 5v output levels Jan 14 17:45:27 Thanks AchiestDragon, my link did have an example using the 244... Will make sure I check.... **** ENDING LOGGING AT Mon Jan 15 02:59:58 2007