Is SWD-only BMP practical, and on Low-pin-count STM32?

devan
Posts: 39
Joined: Sat May 14, 2016 1:45 am

Re: Is SWD-only BMP practical, and on Low-pin-count STM32?

Postby devan » Sat May 28, 2016 9:07 pm

jonr wrote:The drag and drop feature in DAPLink requires custom flash writing code for each target processor. So it's far from being a universal adapter that (fully) works with a large number of MCUs.

IMO, DAP42 gets bonus points for being more open.


DAPLink does both target-agnostic CMSIS-DAP and the target-specific drag-and-drop flashing, so it's not really a limitation (the normal use-case is to place directly on a development board, but some of them have external debug connectors that can be repurposed to debug other boards).

In terms of openness, I think it's really just a difference of priorities. The DAPLink/mbed HDK firmware is primarily written by ARM/mbed and their industry partners, so using a commercial IDE is a logical choice for them.
They're probably already paying for license keys, support, and licensed middleware (some of which has been partially open sourced in order to include in the mbed HDK project).

It's theoretically possible to make it to build with gcc - they already have a build system that can generate Makefiles.
The particularly un-fun bits are writing shims to make the armcc-specific compiler features work with gcc. I spent a few hours poking at it before deciding that becoming an expert in differences between armcc and gcc was not very rewarding.

In the mean time, I may just borrow their open source drag-and-drop implementation and see if it fits in my project.

jonr
Posts: 14
Joined: Sun May 08, 2016 2:06 pm

Re: Is SWD-only BMP practical, and on Low-pin-count STM32?

Postby jonr » Sat May 28, 2016 9:19 pm

I wonder if you could incorporate the flash writing code from open ocd/BMP/Versaloon/?? so that many MCUs would be supported on release.

I find drag and drop convenient, but certainly not a requirement.

devan
Posts: 39
Joined: Sat May 14, 2016 1:45 am

Re: Is SWD-only BMP practical, and on Low-pin-count STM32?

Postby devan » Sun May 29, 2016 5:01 pm

It would probably be much less effort to add a CMSIS-DAP interface to Versaloon/BMP instead.

The CMSIS-DAP code is fairly self-contained and small - it would need few modifications except for some locking to prevent GDB and CMSIS-DAP from trying to simultaneously control the SWD port.

gbulmer
Posts: 56
Joined: Wed Sep 23, 2015 12:04 am
Location: UK

Re: Is SWD-only BMP practical, and on Low-pin-count STM32?

Postby gbulmer » Sun May 29, 2016 11:55 pm

jonr wrote:...

I find drag and drop convenient, but certainly not a requirement.


I think it is a significant simplification and improvement over a dedicated upload program.
There is no need for a 'loader' to run on the host. The copy command, 'File Save', or any ordinary program can upload. The browser can upload.

I've been in a classroom with a group of students, when Arduino IDEs upload had got broken (we never found out why, maybe IT support, maybe a Windows update, maybe Arduino IDE update, ...).
It would be straightforward to say to IT support, "plug this into a USB port, and copy this file onto the USB stick called 'STM32' on every machine, if they all work, we are good to go".


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