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I have recently built a board using an ATSAMD09D14A-MUT, today it came the time to test it, however problems arose in a strangely annoying manner, when trying to connect to the device i get error 4109 (no device detected), Schematic sensor relevant to the uC

As you can see in the following schematics the setup is quite standard, the only things that can be considered somewhat odd are the pull up resistors (they are quite high in value) and the absence of an oscillator, since it the timing precision required for this application didn't require one.

the steps i took to try solving this issue are the following:

1: reduce the swd frequency down to 32khz

2: change the resistors from 100k down to 50k

3: change the reset resistor to 10k assuming there may be noise in the line

4: build a second programming cable to eliminate that possibility

the result was the same after these steps also, the device was externally powered (i know ice doesn't supply power)

i would really appreciate any help with this since i pretty much eliminated all the possibilities i could think of

Edit: The cable used to connect the device is as follows

Header ICE

pin 1 <-> pin 2

pin 2 <-> pin 4

pin 3 <-> pin 3

pin 4 <-> pin 1

pin 5 <-> pin 10

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  • \$\begingroup\$ What do you connect to the 5 pin header? Are you able to measure the 3v3 and the reset line? \$\endgroup\$ – Tom L. Nov 18 '18 at 6:44
  • \$\begingroup\$ An adapter for a standard 10 pin arm debug probe, pin 1 <-> pin 2 (ice), pin 2<-> pin 4, pin 3 <-> pin 3, pin 4<-> pin 1, pin 5 <-> pin 10 \$\endgroup\$ – diegogmx Nov 18 '18 at 6:46
  • \$\begingroup\$ Basically I'd say that looks ok. I don't think it's a resistor problem since SWDIO/SWCLK are driven signals during debug. Does you debugger detect the correct voltage? \$\endgroup\$ – Tom L. Nov 18 '18 at 6:58
  • \$\begingroup\$ yes, around 3.6v, it is really annoying not to have an oscilloscope at hand \$\endgroup\$ – diegogmx Nov 18 '18 at 6:59
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    \$\begingroup\$ 1. Edit your question to show full reproducible physical wiring details of the SWD connection between the board and the programmer. Beware that the Atmel SWD probes tend to have a pin assignment that is backwards from the usual physical numbering of a connector relative to its physical index, and so are typically used with a cable having one connector crimped on the wrong way around. 2. What definite evidence do you have that the MCU can operate without an external oscillator? 3. Monitor the SWD lines with a scope for activity \$\endgroup\$ – Chris Stratton Nov 18 '18 at 15:08
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And the winner is: Chris Stratton you were right in point 1: the atmel debugger has the pinout inverted, now that i remember, i had to deal with that about 2 years ago, however since in most boards i use 10 pin cables that i had already made i forgot about this issue, its working properly now

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  • \$\begingroup\$ Glad to hear it's working. Your edit to the question doesn't really capture the physical reality of the wiring - you list what you believe the pin numbers to be, but you don't really document the wiring in a way that someone could have used to determine that the physical connections were wrong. So we're left with guessing - luckily that worked. But it's not really how this site is supposed to be used. \$\endgroup\$ – Chris Stratton Nov 19 '18 at 18:09
  • \$\begingroup\$ i think it does chris, thats exactly how the wiring is, the pins match the standard 10 pin arm debugger and the standard numbering of an idc flat connector, the thing is that for some reason atmel got it completely backwards as you point out \$\endgroup\$ – diegogmx Nov 20 '18 at 2:53
  • \$\begingroup\$ The fact that one can't tell from your question that it is backwards is exactly the physical wiring detail that is missing from your question. You supplied only logical documentation, not physical. \$\endgroup\$ – Chris Stratton Nov 20 '18 at 4:43

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