Black Magic Probe (GDB): \\.\/dev/ttyACM0: No such file or directory

[probonopd]

Have flashed Black Magic Probe firmware to a Blue Pill board as described on http://www.stm32duino.com/viewtopic.php?f=37&t=2801#p36730:

stm32flash -w blackmagic.bin -S 0x08000000 -v /dev/ttyUSB0

The system does see the device:

$ cat /etc/*release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04

$ lsusb
Bus 008 Device 012: ID 1d50:6018 OpenMoko, Inc. 

$ dmesg
[16845.933046] usb 8-1: Product: Black Magic Probe (STLINK), (Firmware v1.6.1-101-g5686550-dirty)
[16845.933048] usb 8-1: Manufacturer: Black Sphere Technologies
[16845.933051] usb 8-1: SerialNumber: ...
[16845.939092] cdc_acm 8-1:1.0: ttyACM0: USB ACM device
[16845.942083] cdc_acm 8-1:1.2: ttyACM1: USB ACM device

$ ls -lh /dev/ttyACM*
crw-rw-rw- 1 root dialout 166, 0 Feb 16 13:23 /dev/ttyACM0
crw-rw-rw- 1 root dialout 166, 1 Feb 16 13:23 /dev/ttyACM1

Connections for the programmer on /dev/ttyACM0:

Blue Pill	nRF51822 module
3.3	VDD
GND	GND
PA5	SWCLK
PB14	SWDIO

Optional for serial monitor on /dev/ttyACM1:

Blue Pill	nRF51822 module
PA2 (TX)	P0.00 (RX)
PA3 (RX)	P0.01 (TX)

However, if I try to upload a sketch using the Black Magic Probe (GDB) programmer from the Arduino IDE, I get:

Sketch uses 1296 bytes (0%) of program storage space. Maximum is 262144 bytes.
\\.\/dev/ttyACM0: No such file or directory.
"monitor" command not supported by this target.
Don't know how to attach.  Try "help target".
You can't do that when your target is `exec'
Don't know how to run.  Try "help target".
Reading symbols from sketch_feb16a.ino.elf...done.
Temporary breakpoint 1 at 0x322: file /home/me/.arduino15/packages/sandeepmistry/hardware/nRF5/0.5.0/cores/nRF5/main.cpp, line 29.

Program complete!

I don't think it has actually done anything since it could not find the device.

Note the extra \\.\ in \\.\/dev/ttyACM0: No such file or directory. @sandeepmistry also has the extra \\.\ in #196 (comment).

[probonopd]

If I delete all \\.\ from platform.txt and programmers.txt, then I do not get this error.

Success!

Now I get:

Sketch uses 1296 bytes (0%) of program storage space. Maximum is 262144 bytes.
Target voltage: unknown
Available Targets:
No. Att Driver
 1      Nordic nRF51
Remote debugging using /dev/ttyACM0
Attaching to Remote target
0xfffffffe in ?? ()
Reading symbols from sketch_feb16a.ino.elf...done.
Loading section .text, size 0x510 lma 0x0
Loading section .ARM.exidx, size 0x8 lma 0x510
Loading section .data, size 0x6c lma 0x518
Start address 0x1f0, load size 1412
Transfer rate: 10 KB/sec, 353 bytes/write.
Temporary breakpoint 1 at 0x322: file /home/me/.arduino15/packages/sandeepmistry/hardware/nRF5/0.5.0/cores/nRF5/main.cpp, line 29.
Starting program: /tmp/arduino_build_965627/sketch_feb16a.ino.elf 
Note: automatically using hardware breakpoints for read-only addresses.

Temporary breakpoint 1, main ()
    at /home/me/.arduino15/packages/sandeepmistry/hardware/nRF5/0.5.0/cores/nRF5/main.cpp:29
29	  init();

Program complete!

[dlabun]

By any chance do you have an actual black magic probe to test with? I don't own either device to test with unfortunately. I am just wondering if this anything to do with the fact that the BMP firmware has been recompiled for a different board.

[probonopd]

Working for me now. So at least on Linux, the \\.\ definitely needs to be removed.

[dlabun]

@sandeepmistry can you take a look at this? I don't have a clue when it comes to Linux

[probonopd]

These STM32F103C8 Blue Pill boards can be had for around $2 and might become quite popular as nRF5x programmers with the BMP firmware. Performing very well for me now, with the change described above.

[mristau]

From the BlackMagic Readme

Note: On Mac OS X use the /dev/cu.usbmodem. Don't use the tty version of this device as this one will freeze gdb when it tries to open it.
On Windows, use the the COM port instead of /dev/ttyACM0. For ports >= COM10, add the prefix \\.\, for example:

target extended-remote COM3
target extended-remote \\.\COM10

[probonopd]

While \\.\ should be used on Windows with COM-Ports higher than 10, the \\.\ entirely prevents this from working from anything but Windows. No other core uses the \\.\ Windows workaround.

Please merge my pull request. The documentation states that \\.\ needs to be used on Windows with COM-Ports higher than 10. But it should not be the default.

[micooke]

@probonopd - you are correct in that the \\.\ is a workaround for gdb in windows, i believe i have had to use it for stm32flash or dfu-util as well. Just a point that the documentation is a incorrect as \\.\ works for any COM port in Windows, i.e. < COM10 as well as >= COM10. Thanks @mristau for digging up the reference!

With your PR#247 - could you instead insert -ex "target extended-remote {serial.port}" -ex "target extended-remote \\.\{serial.port}" so that it works in Windows for COM >=10 as well as working for linux!?

gdb isnt harmed by a second target call, it just uses the last valid attachment. Example outputs from this patch are below:
COM30: No such file or directory.
Remote debugging using \\.\COM30
or
Remote debugging using COM9
Remote debugging using \\.\COM9

Scratch that, it uses the last attempt even if that breaks.

This may require two configurations, one for Windows with the preceding \\.\ and one for linux/mac without.
@dlabun, @sandeepmistry - thoughts?

[probonopd]

How do other Arduino cores handle this? How common is it to have a 2-digit COM port in Windows? I haven’t encountered this topic with other cores so far that also upload via the serial port (e.g., Arduino Uno).

[dlabun]

Honestly, I don't use the BMP or Linux so my opinion how to fix the problem isn't valid... I do know 2 digit COM ports are rather common on Windows, my Arduino Zero is up in the COM60 range.

[mristau]

windows keeps track of many COM-devices, we develop a board and it's fairly common that first boards start at COM3-4 but i have some that are also high up like COM30-40
I don't know how the platform.txt works, can't there be a version for linux and another for windows inside, like
linux.tools.blackmagic...

It seems there is a way to separate by operating system

tools.esptool.cmd=esptool
tools.esptool.cmd.windows=esptool.exe

that is from the platform.txt of the ESP8266 Arduino Core

[probonopd]

That could be the solution then

[dlabun]

If somebody can write a PR and test it, I would be available to issue an urgent release this weekend.