On 24.02.2018 0:04, Jay Maynard wrote:

With Paul’s help, I wiggled the SRST line from the console. It’s showing low pretty much no matter what I do.

Strange. If SRST were asserted why SWD fails randomly?

The SWD lines are pulled up to 3.3V (the same supply that powers the processor) by 100K resistors. That strikes me as an awfully high value. Too much? Should I try lowering it, to, say, 4.7K?

No, it's not necessary if not used in harsh environment. It's not a 'working' pullup for OC drivers like in I2C. The only reason is to prevent signals to roam when not driven - when adapter is not connected or inactive. More important is a small series resistor (33 ohm) on SWD - ringing prevention. Again not necessary if the cable to adapter is short.

Did you try to change adapter_khz? I would test 100 and 3000 kHz.
Did you checked all supply pins?

Tom

*From:*Tomas Vanek [mailto:tom_...@users.sourceforge.net]
*Sent:* Friday, February 23, 2018 4:38 PM
*To:* Jay Maynard <jmayn...@kahlerautomation.com>
*Cc:* openocd-devel@lists.sourceforge.net
*Subject:* Re: [OpenOCD-devel] Atmel ATSAME70 examination incomplete at startup

I connected my custom SAME70 board to a FT2232 based adapter just to make sure that current git master works.
It does. See attached log in -d4 level as you used.

There must be some electrical problem in SWD signals, grounding or supply.

Tom

On 23.02.2018 23:06, Jay Maynard wrote:

    Apologies for the triple post. Can I drop an anvil on Sourceforge now?

    Anyway, a couple of updates since that was written:

     1. I tried setting the bits in the write command to 0. Didn’t
        change the result.
     2. A scope on the SWD data line shows nice clean square waves for
        the signal, so that much is good electrically, at least.

    I have a debug log from someone using a SAME70 Xplained
    development board, but it uses the CMSIS-DAP debugger interface.
    I’d prefer not to buy another debugger dongle, but I will if I
    have to. One weisenheimer suggested I get an Atmel-ICE while it’s
    on sale for 50% off ($65 for the kit). Anyone out there using a
    SAME70 that’s **not** on the Xplained board?

    *From:* Jay Maynard [mailto:jmayn...@kahlerautomation.com]
    *Sent:* Friday, February 23, 2018 3:28 PM
    *To:* openocd-devel@lists.sourceforge.net
    <mailto:openocd-devel@lists.sourceforge.net>
    *Subject:* [OpenOCD-devel] Atmel ATSAME70 examination incomplete
    at startup

    I’m trying to get an Atmel ATSAME70Q20A working with OpenOCD. I
    have an Olimex JTAG-TINY and ARM-JTAG-SWD connected, and the
    system works with our previous board running an AT91SAM7X. This is
    a new board design, so there may be a hardware issue. I’ve tried
    both the 0.10.0 distribution release and the tip of the git
    repository tree built today (from the Czech mirror, since
    Sourceforge seems not to have git access running yet).

    The results vary some between runs. Sometimes, it doesn’t power up
    the debug domain (see https://pastebin.com/NHXavQQL for an
    example). Other times, it gets the debug domain powered up, but
    can’t find the AHB-AP (see https://pastebin.com/X4XeFdam ). Still
    others, it finds the AHB-AP, but then gets a fault trying to write
    to it (see https://pastebin.com/KQtpF537 ). The last case, at
    least, seems to have a problem: two bits are being written as 1 to
    a register that the architecture defines as should be zero.

    I’ve spent some time online on the IRC channel trying to get this
    running with the help of some folks there, but no luck. They
    suggested I ask you folks. Any ideas?

    Jay Maynard | *Software Engineer*

    Kahler Automation<http://www.kahlerautomation.com/>| 808
    Timberlake Road, Fairmont, MN 56031 | Main: 507-235-6648

    jmayn...@kahlerautomation.com <mailto:jmayn...@kahlerautomation.com>

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