Yep, that blue light is blinking and I made it happen. I’ve been hard at work since I got my free STM32F0-Discovery board in the mail. Most recently I put together a starting template for building STM32F05x project on Linux. You’ll still need to install your own tool chain (I’m using the Code Sourcery G++: Lite Edition), but this makes it a snap to compile your projects with support for STM’s peripheral libraries.
As for programming, you may remember that I added support for writing to RAM in the stlink project. I’ve
wasted spent a ton of time trying to get support for writing to Flash into that project. It’s just less of a hassle to use stlink than it is to work with OpenOCD. But I’ve really hit a wall getting the flash loader code to work. If you want to check out what I’ve done so far in that area I committed a very messy branch (see the commits for what code changes I’ve made).
In the mean time you can use OpenOCD to write images compiled with the template to your device. I included the ‘make program’ option in the Makefile to do this from command line. If you need help compiling OpenOCD check the readme in the template repository.
Last Wednesday I posted a video review of the new STM32F0-Discovery board which is built around an ARM Cortex-M0 chip. I speculated that it should work with the open source project aimed at programming these discovery boards. I tested it out and a connection could be made, but no code could be flashed. So I spent a few hours over the weekend and added support.
My updates are already in the stlink repository. After cloning the code, you can use three commands to compile the software (./autogen.sh, ./configure, make). That’s assuming you have all of the necessary dependencies (I had to install libusb-1.0-0-dev) and that you add the udev rule suggested in the documentation (also found in the repository). The program st-util connects to the board and provides a listening port for an ARM debugger (I’m using arm-none-eabi-gdb from CodeSourcery G++ Lite).
When I first started testing, the chip id was reporting as 0. It turns out the register address polled for this information was wrong. After finding that in the almost-900 page reference manual I went through the painstaking process of finding the hex values necessary to properly memory map the device. From there I also updated the blink example to generate an ELF file compatible with the Cortex-M0 chip. So out of the gate you should be able to use an ARM cross compiling toolchain to compile the example, connect to the board with this utility, then use the debugger from the toolchain to connect and flash that example to RAM.
There’s lots more to be done. To fully utilize the chip it is necessary to use a startup file and linker script when compiling. I’ve done nothing in this area, but I hope to work on some tutorials as I get further along. Of course if you have your own successes developing for this board using a Linux machine we want to hear about it!
The STM32 Discovery boards are nothing new, we’ve looked at them several times. But the newest sibling in the line might be just the thing to make the leap from your steadfast 8-bit projects. We got our hands on it and recorded a video review.
The STM32F0-Discovery gives you a programmer and ARM Cortex-M0 chip all on one convenient board. The top portion is the ST-Link V2 programmer, and includes jumpers and a programming header which let it easily program off-board chips.
The included microcontroller is an STM32F051R8T6 which includes 64kb of program memory and 8kb of RAM. Coming in at $1.80-3.77 in single units and in a hand-solderable LQFP package this raises an eyebrow for our future projects. It has an 8 MHz internal oscillator with 6x PLL which means you can run at 48 MHz without an external crystal (check out [Kenneth Finnegan's] PLL primer if you don’t know what this is).
The only thing holding us back is the development environment. ST provides everything you need if you’re on Windows, but we want a Linux friendly solution. We know other Discovery boards have worked under Linux thanks to this project. This uses the same ST-LINK V2 so it should work as well. If you want one of your own head over the ST page to see if they’re still giving away samples. There should be a button labeled “Register for your FREE KIT”.