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:[email protected]]
*Sent:* Friday, February 23, 2018 4:38 PM
*To:* Jay Maynard <[email protected]>
*Cc:* [email protected]
*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:[email protected]]
*Sent:* Friday, February 23, 2018 3:28 PM
*To:* [email protected]
<mailto:[email protected]>
*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
[email protected] <mailto:[email protected]>
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