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1. 

   drinkdhmo
   Member

   I am currently programming an attitude controller/possible autopilot for my RC airplane using a Maple Mini. The Mini has worked very well for me and the FreeRTOS library has been nice and easy to work with. Right now I have the attitude heading reference system (AHRS) working with a MiniIMU-9 v2 from Pololu. It calculates quaternions and decently fuses the absolute sensor data with the gyro data. (I can post code if anyone wants it).

   I developed this code in two parts, one using the RTOS that schedules tasks to interface with the RC equipment. The other part was just a development process for the AHRS. When I merged it into the RTOS, I started getting really strange behavior, i.e. the processor would halt at random times during execution. After some investigating, I found I was bumping up against the 120k program size limit. My hypothesis is that my stack didn't have enough room and would randomly run into something that caused the processor to halt.

   Long story short, I'm not asking for help with this problem (unless it isn't what I think it is and the solution is simple), I am looking to upgrade my microcontroller to something with a bit more room. My first hope was that the Maple native 2 would be around to move into. Alas, no such luck. I have been looking at the FEZ Cerbuino Bee as an alternative. I don't like the idea of tying my hands with C# and the .net micro framework, so I am wondering if anyone knows how hard it would be to use the Maple command-line toolchain to program this board and what it would take to port my code.

   Thanks in advance!

   Posted 3 years ago #
2. 

   ala42
   Member

   For developement you could get the STM Discovery F4 board, which also has an on board SWD debugger for just ~$15. As you seem to like the Maple Mini footprint, you might take a look at the FEZ Cerb40. For some strange reason they have not mounted the 3.3V regulator on the bottom side of this tiny board.
   You can use the CodeSourcery toolchain and my libmaple F4 port, which is available at https://github.com/AeroQuad/AeroQuad/tree/development/Libmaple. Most libmaple functionality is ported in the mean time. The discovery F4 board is supported.
   Adding a new board type using a different pinout is not that complicated, as there are already several examples for that in the code.

   Posted 3 years ago #
3. 

   Xavier
   Moderator

   Drinkdhmo, I just read you email.
   I uploaded a minimal/test project here.
   http://xhosxe.free.fr/cerb40.tgz
   Makefile, startup and linker for the ARM gcc :
   https://launchpad.net/gcc-arm-embedded/+milestone/4.6-2012-q2-update
   The hardware FPU is activated and i checked the STM32F4 FPU instruction shows up in the assembly.
   I've read that the CodeSourcery toolchain do not allow hard FPU code.
   Ala42, is it true ?

   The cerb40 is not as easy as the maple mini to play with.
   It does not have a 3.3V regulator.
   And is not provided with a bootloader.

   So you'll have to flash it with a stlink-v2 interface... SWD works well.
   To flash, I use texan/stlink software for linux.
   https://github.com/texane/stlink
   Under windows you can use the one provided by ST.

   You can try to use the STM32F4 firmware library, nice page here :
   http://www.emcu.it/STM32F4xx/STM32F4-Library/STM32F4-Library.html
   But's it's not as simple as libmaple...

   Xavier

   Posted 3 years ago #
4. 

   ala42
   Member

   The F2/F4 CPUs have an built in boot loader that supports flashing over USARTs and USB. The F1 CPUs have a built in boot loader that supports just flashing over USART1. These are available when the CPU comes from STM and do not use any of your application flash memory.
   The USB boot loader you use on a Maple mini is just a preflashed program located in the lower part of the flash memory, flashed by leaflabs, eating up some of your application flash memory.

   Softfp does NOT mean software emulation of a FPU, it uses the CPU built in FPU using the assembler commands in exactly the same way hardfp does. The difference between hardfp ABI (Application Binary Interface) and softfp ABI is just the way float values are passed when calling library functions. Your code does use the FPU instructions, which you can test by placing a float on a non word aligned address, as the FPU does not like this and throws an exception. Library functions could use emulation using the softfp ABI.

   Posted 3 years ago #
5. 

   fuzzy
   Member

   Hi all, sorry to resuscitate this thread but i'd like to use the fez_cerb40 with the maple library but i can't find any hits on how to integrate the example provided by @Xavier with libmaple cloned from aeroquad github repo.

   Posted 2 years ago #

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