Moving from Arduino to STM32F072

[Jester]

In a previous post, I asked for suggestions on libraries and suitable uC to drive a QVGA display in this post:
  https://www.eevblog.com/forum/projects/firmware-for-spi-qvga-display/msg1419546/#msg1419546

Based on feedback from that post, I ordered an Arduino MKRZERO and with all the available support libraries, it was pretty much painless to get everything working as desired: display, touch screen, scanning A/D 's etc.

I now want to take the next step and get the code that's running on the MKRZERO board, on a non Arduino equipped ARM Cortex M0 board.  I discovered that the ease of use of the Arduino environment is great for getting something up and running really quickly, however you pay a big price speed wise and because this may eventually turn into something that resembles a product, I think it would be wise to break from Arduino sooner rather than later. I would prefer to start with a free C/C++ development tool

So I'm now looking for a non Arduino Cortex M0 development board with appropriate debugger equipped IDE.

•   -  I already have CCS from some past DSP work, however TI development boards are M4 based and too expensive for this design and support for M0 sounds iffy at best.
•   ?  Option 1:  Microchip ATSAMD21-XPRO  https://www.digikey.com/products/en?keywords=ATSAMD21-XPRO  I would try using Atmel Studio, not sure how good or bad this is? Free IAR is limited to 16K, and I'm already at 45k so IAR and Keil are a non starter.
•   ? Option 2:  STM32F072B-DISCO   https://www.digikey.com/products/en?keywords=STM32F072B-DISCO%20  , need to look into available IDE and debugger, suggestions?

 
If you had to pick between these two, which one would you recommend?  Or if there are better options I'm all ears.

Thanks EEVBLOGers 

[ataradov]

I would recommend a simple breakout board and a separate debugger. Debuggers for ARMs are quite cheap, and this will open up your options for microcontrollers.

Also, boards with a lot of stuff integrated are really annoying. There is always a pin that you need, but it is not brought out on the connectors.

[Jester]

I would recommend a simple breakout board and a separate debugger. Debuggers for ARMs are quite cheap, and this will open up your options for microcontrollers.

Also, boards with a lot of stuff integrated are really annoying. There is always a pin that you need, but it is not brought out on the connectors.

Can you recommend a debugger?

[ataradov]

Can you recommend a debugger?

That depends on your budget. If you want to go for a generic CMSIS-DAP debugger that is going to be supported by nearly all tools, then LPC Link 2 is a very good deal. It does not come with CMSIS-DAP firmware, but can be updated with one.

IBDAP is another great option for a generic CMSIS-DAP debugger.

If you want to go for something more expensive (and with a case), then Atmel-ICE is a good option. It acts as a CMSIS-DAP debugger, and will works with most tools.

Stuff from Segger is way more expensive, but I don't know if it is any better for it.

[mbless]

I think the easiest/fastest way to get up and running is to buy a copy of Mastering STM32 and a STM32 nucleo dev board. It has a built-in programmer and debugger using OpenOCD. A bonus is that you can break off the programmer/debugger for something else. Of course I’m biased as I only use STM32 and have never used Microchip MCUs.