Re: Cortex-M0 BPS creation

2014-09-22 Thread Pavel Pisa
Hello Sebastian and Oleg,

On Monday 22 of September 2014 07:35:38 Sebastian Huber wrote:
 On 22/09/14 06:36, Мороз Олег wrote:
   Hello everyone. i'm new to  BSP development.  We have a project
  which is uses some kind of cortex-m0 microcontroller. As i understand
  it's armv6-m family. Is this CPU family is supported by rtems? I'm
  reading the book called BSP and device driver development guide  and it
  says look at
  cpukit/score/cpu/CPU. This directory contains only armv7-m and armv4
  files. Is it correct?

 The armv7-m support will probably work also for a Cortex-M0.

I think that M3 context switch would be mostly OK.
Exception and interrupts model is the same as for M3,
but I have feeling that there exists option to
use some simplified one - but it can be for M1.
But you need to use M0 specific GCC options.
We use GCC for nRF51 Cortex-M0 with next options

  arm-none-eabi-gcc -mcpu=cortex-m0 -mthumb --std=gnu99 -Wall -mfloat-abi=soft 

Else GCC can use Thumb2 instructions which are not supporeted
by ARMv6-m. For example Thumb instructions CBZ, CBNZ, IT
emitted by GCC for M3 are not supported by M0.

So toolchain rebuild is required for sure.

Best wishes,

 Pavel

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Re: Cortex-M0 BPS creation

2014-09-21 Thread Sebastian Huber

On 22/09/14 06:36, Мороз Олег wrote:

 Hello everyone. i'm new to  BSP development.  We have a project which is
uses some kind of cortex-m0 microcontroller. As i understand it's armv6-m
family. Is this CPU family is supported by rtems? I'm reading the book called
BSP and device driver development guide  and it says look at
cpukit/score/cpu/CPU. This directory contains only armv7-m and armv4 files.
Is it correct?


The armv7-m support will probably work also for a Cortex-M0.

--
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
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