February 10, 2017 at 17:13 #10357February 10, 2017 at 22:58 #10365
Hi – I had a similar issue, perhaps this thread may be helpful:
fwiw – I ended up buying Olimex hardware (both the JTAG programmer & ESP8266 EVB) from Mouser Electronics. I had more success, but things still did not work out quite as one might expect.
See also my thread on the Olimex forum that may be of interest:
I plan to revisit the Segger this weekend & will post my results. One thing that may have been reckless on my part: I used a nice parallel cable with the Olimex, and an octopus of loose wires with the Segger:
Lame, as my background is in electronics and I should know that the alternating parallels of ground wire can significantly reduce the noise and interference on the signal lines.February 11, 2017 at 00:15 #10373
The “Error: JTAG scan chain interrogation failed: all zeroes” error almost 100% indicates a wiring problems (that also includes power and reset issues). Hence our best advice is to get exactly the same hardware as shown in the tutorial, get it to work and once you get a stable reference point, start experimenting with different boards.February 14, 2017 at 08:40 #10411
Thank you guys for your answers!
I don’t expect that my problems come from “octopus” wiring/cableling rather than an ESP8266 issue together with Segger J-Link and Windows 10 driver and VisualGDB… It all looks quite shaky and unstable to me. And I don’t like the kind of problems. I would like to focus on my application.
I triple checked my wiring and I still can’t find an error (I made one silly mistake at the beginning, but since then couldn’t find a mistake in wiring).
I don’t want to loose too much time here and I do not want to buy a new debugger hardware. So I may try debugging over serial interface / UART. I hope this is more stable?
Again: many thanks to you for the support.February 19, 2017 at 19:45 #10479
Yes, the gdb stub-based debugging should not be affected by the JTAG wiring issues, so we would recommend trying it if JTAG does not work.February 19, 2017 at 23:16 #10484
The “Error: JTAG scan chain interrogation failed: all zeroes” error almost 100% indicates a wiring problems (that also includes power and reset issues).
I’d like to add that I’ve recently found that simply power-cycling the ESP8266 and JTAG programmer has resolved my “all zeros” problem as well.
But I agree that adequate power is important, as well as understanding the reset line (e.g note the NodeMCU can control the reset line via serial port RTS/DTR lines)
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