Parallel programing using pyocd

[Thomas-Lawrence]

Hi,
I am trying to do parallel programming using pyocd.
Details of my system :
Target : HC32F460
Interface: CMSIS-DAPLink

I was able to flash the target using pyocd and now I am trying to flash several targets in parallel. To start with I connected two targets to two separate interfaces. The pyocd commands are then amended with the unique IDs of these interfaces and created two threads to do flashing, but it fails! I have tested both the interfaces individually and in both cases the target was successfully flashed.
Is it possible to do parallel programing with pyocd? I am new to python world and any suggestions would help.

[Hoohaha]

Are you using the APIs to in your threads?
I am not sure pyocd APIs can support in multiple threads.

I think you can use multiprocessing pool to launch pyocd command line to perform the flashing tasks. It would be easy and more stable.

[Thomas-Lawrence]

Hi,
I am working on Windows platform. In this case I am trying to use 2 probes each connected with a target controller.

Regarding the driver, I followed the libusb installation documentation and was working fine for a single probe but it started giving issues when I tried to control two probes from separate threads at the same time.

Yes I have hidapi installed, see below

Package Version

---

cmsis-pack-manager 0.2.10
hidapi 0.10.0.post1
pyocd 0.30.2
pypiwin32 223
pyusb 1.1.0
pywin32 228

[flit]

Thanks for the info.

It would be helpful to know which version of CMSIS-DAP is being used. (DAPLink supports both.) That changes which USB backend is used in pyocd. libusb will only be used for CMSIS-DAPv2 (and STLink and picoprobe), which use WinUSB instead of HID since it's faster while still not requiring a kernel driver on Windows.

Would you mind running:

pyocd cmd -u 0000000300190051044ab7bd00000c120000000097969921

then when the "pyocd>" prompt appears run this (the "$" is part of the command and must be typed; it starts a Python expression):

$probe._probe._link._interface

This will print something like:

<pyocd.probe.pydapaccess.interface.hidapi_backend.HidApiUSB object at 0x10b575070>

[Thomas-Lawrence]

Hi,
CMSIS DAP version used is 'ARM CMSIS-DAP v1'.
Please see log below,

X:>pyocd cmd -u 0000000300190051044ab7bd000007780000000097969921 -t HC32F460xE
Connected to HC32F460xE [Lockup]: 0000000300190051044ab7bd000007780000000097969921

pyocd> $probe._probe._link._interface
<pyocd.probe.pydapaccess.interface.hidapi_backend.HidApiUSB object at 0x00000193F967B288>

pyocd> exit

[flit]

Perfect, thanks! That confirms that pyOCD is using hidapi. Let's try an experiment by switching to pywinusb, and see if that resolves your problem. Even if it does fix things, there's still a need for a real fix, either in pyocd or upstream in hidapi. We can't just switch back to pywinusb, since there a some debug probes that don't work with it and it hasn't been updated in years.

Please run these commands:

pip install pywinusb
set PYOCD_USB_BACKEND=pywinusb

Then try your tests with pyocd again. Setting the PYOCD_USB_BACKEND environment variable overrides the default selection.

I'll also try to reproduce in my Windows VM and work on fixing the problem.

[Thomas-Lawrence]

Hi Flit,
Finally the parallel programing works :).
It was actually my mistake, one of the commands was actually pointing to the same device from both threads , which caused issues with the DAP response. I would like to thankyou for your support.

From my testing both hidapiusb and pywinusb backends works fine for parallel programing.