IRC log for #openjtag on 20070808

03:03.47*** join/#openjtag ka6sox-away (n=ka6sox@204.16.19.246)
03:13.01*** join/#openjtag rwhitby (n=nnnnnnrw@nslu2-linux/rwhitby)
03:57.22*** join/#openjtag ka6sox-away (n=ka6sox@204.16.19.246)
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05:27.11*** join/#openjtag knoppix_ (n=knoppix@gimpelevich.san-francisco.ca.us)
09:55.09*** join/#openjtag pleemans (n=peter@d51A5E76A.access.telenet.be)
09:56.59*** join/#openjtag pleemans (n=peter@d51A5E76A.access.telenet.be)
13:03.43sn9anybody around?
13:04.15sn9i'm finally getting the chance to try openocd
13:05.11drathhey
13:05.25sn9i'm getting this error: number of discovered devices in JTAG chain (51) doesn't match configuration (1)
13:05.42sn9i think it's some reset protocol mismatch
13:05.44drathwhich JTAG interface do you use, which target, and which version of the openocd?
13:07.03sn9wiggler, arm926ejs, 2007-07-31 19:00 CEST
13:10.45sn9drath: any ideas?
13:13.58drathwell, it's a very low-level commuication problem
13:14.21draththe OpenOCD scans a fixed bit pattern in, and reads out the IDCODEs
13:14.33drathin your case it's receiving somewhat random data
13:14.45drathwhich arm926ej-s exactly?
13:14.58drathis it a geniuine wiggler?
13:16.11sn9it is not from macraigor
13:16.22sn9the SoC is marvell
13:16.30draththen it's not a real arm926ej-s ;)
13:16.54drathit just identifies itself as one, but marvell has a license that allows them to modify the original ARM ip
13:17.26drathare you on windows or on linux?
13:17.31sn9lin
13:17.40drathdid you build with ppdev support?
13:17.43sn9yes
13:17.53drathdid you remove the "lp" module?
13:18.20sn9whoops
13:18.38drathit's not strictly necessary, but I've seen all kinds of weird behaviour with parallel ports
13:19.00drathwhere did you get your wiggler from - something you've built yourself?
13:19.07sn9nah
13:19.41sn9ok, now the number changed from 51 to 20
13:19.53drathheh, that's equally bad
13:21.13sn9is srst parport pin 2 or trst?
13:24.38sn9as far as the software is concerned, that is
13:25.52drathpin 2
13:26.00drathand it should not be inverted
13:26.11sn9then where is srst expected?
13:28.44drathpin 6, and it should be inverted
13:30.29sn9pin 6 unused here, and pin 2 == RST, going to nTRST through a transistor
13:30.39*** join/#openjtag prpplague (n=billybob@mail.americanmicrosystems.com)
17:38.30sn9drath: still there?
17:43.54*** join/#openjtag rd_ (n=rd@toi.yeu.phu.nu)
17:48.46sn9rd_: hi
18:27.20*** join/#openjtag Chocobo (n=swinchen@strongbad.eece.maine.edu)
18:36.01*** join/#openjtag rd_ (n=rd@toi.yeu.phu.nu)
19:02.25*** join/#openjtag ka6sox-away (n=ka6sox@204.16.19.246)
19:03.40sn9drath: according to the source code, it's the other way around -- pin 2 is srst, and pin 6 is trst
19:05.28sn9pin 6 is unused on my wiggler thing
20:33.44drathsn9: hey
20:34.00drathsn9: let me double check that
20:34.09drathsn9: in only had a brief look at some old drawings
20:35.51sn9i'm trying different possible cable definitions atm
20:37.11drathyou are right, the code has ntrst at pin 6, nsrst at pin 2
20:37.16drathso that's the "genuine" wiggler layout
20:39.16sn9i'm comparing three schematics:
20:39.16sn9http://www.k9spud.com/jtag/schematic-1.0.php
20:39.16sn9http://www.diygadget.com/images/jtag/wiggler/wiggler.buffer.jtag.fta.schematic.jpg
20:39.16sn9http://wiki.dns323.info/_media/hardware:dns-323-jtag.pdf?id=hardware%3Ajtag&cache=cache
20:39.39draththere's a great deal of confusion
20:40.01draththe definition labeled "wiggler" in the OpenOCD source is known to work with original wigglers and the ARM-JTAG from Olimex
20:40.24drathit is also the one used by Amontec's chameleon in its Wiggler configuration, but only by the latest update
20:40.35drathI think this one is the "original" layout
20:40.45drathbut you can easily add a layout of your own
20:41.59sn9the board has the same jtag pinout as the dns323, i.e. only one type of reset line
20:42.12sn9http://wiki.dns323.info/hardware:jtag
20:42.30sn9the cable is the diygadget one
20:43.48sn9according to the debug log, parport_reset() always gets called only once, to deassert both lines
20:44.40sn9after that, "TRST asserted" always gets reported three times
20:45.40sn9i did not use a resistor on the EN line -- plugged it straight into Vcc
20:46.41sn9drath: any ideas?
20:49.18sn9if i mark pin 2 as a non-inverted signal, the device stays in a halted state
20:53.22drathTRST asserted is also called when the TMS sequence that moves to Test-Logic-Reset executes
20:54.02drathyou could try old_amt_wiggler
20:54.26draththat one has D0 (Pin2) as an inverted nTRST signal
20:55.17drathuse "reset_config trst_only" in the .cfg file
20:56.49sn9<PROTECTED>
20:56.49sn9<PROTECTED>
20:56.50*** join/#openjtag juanpaul (n=juan@189-20-46-108.asernet.com.br)
20:57.06sn9those are what i'm trying now
20:57.59sn9no luck so far
20:59.01drathwell, that's the main problem with parallel ports - you never know why they fail
20:59.27drathhave you been able to use this PC's parallel port with some other paralle port JTAG software?
21:00.24sn9have not tried
21:01.00sn9i know pin 2 is responsive, because if i don't invert it, the device stays in a halted state
21:01.38*** join/#openjtag drath_ (i=vmaster@p5B07E72F.dip.t-dialin.net)
21:02.01sn9i know pin 2 is responsive, because if i don't invert it, the device stays in a halted state
21:03.31drathdid you try lowering the JTAG speed (higher jtag_speed divisor)
21:03.53sn9i thought that was ignored for parport
21:05.02drathno, it's used to output the same pattern (jtag_speed+1) times, effectively diving the maximum frequency
21:06.51sn9how much higher should i make the jtag_speed?
21:07.27drath1 or 2
21:07.52draththat results in a frequency of 100 kHz or so
21:24.33sn9how do i tell whether to use push_pull or open_drain?
21:24.55drathin your case it doesn't matter
21:25.04sn9because?
21:25.05draththat's for cables that allow the reset lines to be either of both
21:25.36sn9how do i tell the difference between the reset line types?
21:25.37drathin your case the reset line is open-drain, which inverts it
21:26.16sn9ah, ok
21:48.20drathi'm off for today, bye sn9
21:48.28sn9ok
21:56.14*** join/#openjtag dwery (n=dwery@nslu2-linux/dwery)

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