stm32 external SRAM
Christian Mauderer
christian.mauderer at embedded-brains.de
Mon Jun 17 06:45:19 UTC 2019
If you put any sections into the external RAM that need initialization,
you have to init the RAM before the BSP copies it's sections. The STM32
BSP copies it's sections in bsp_start_hook_1(). So either put it in
bsp_start_hook_0 or in bsp_start_hook_1 before the copy_section calls.
Attention: You can't use much in these functions. They are in a very
early initialization stage. So be careful what you put there.
If you only want malloc to allocate memory from there, there might is a
later point where you can do that.
On 17/06/2019 08:32, Jython wrote:
> Thank you and the example! that is to say put extern sram init in
> bsp_start( void ) function?
>
> On Mon, Jun 17, 2019 at 1:04 PM Christian Mauderer
> <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>> wrote:
>
> On 17/06/2019 03:05, Jython wrote:
> > STM32:
> > 112KB at 2000 0000
> > 16KB at 2001 C000
> >
> > external sram : 1MB at 0x68000000
> >
> > does MEMORY layout support RAM2?
>
> Hello Jython,
>
> you can distribute the regions to the two RAMs. For example this BSP
> does that:
>
> https://git.rtems.org/rtems/tree/bsps/arm/lpc32xx/start/linkcmds.lpc32xx_phycore
>
> Please note that you have to take a detailed look at what is used till
> your external RAM initialization run and what not. But if you put your
> external RAM initialization in an early enough step, you shouldn't get
> problems with that.
>
> Best regards
>
> Christian
>
> >
> > On Fri, Jun 14, 2019 at 10:13 PM Christian Mauderer
> > <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>> wrote:
> >
> > If you have already added the chip and it is initialized
> during startup,
> > you most likely have to add a section for it in your linker
> command
> > file. Depending on where your internal RAM is located and
> where the
> > external one is: If they are continuous that can be enough.
> >
> > Best regards
> >
> > Christian
> >
> > On 14/06/2019 04:42, Jython wrote:
> > > we have added 1M ram by FSMC, and want to manage it by
> system malloc
> > > controler
> > >
> > > On Fri, Jun 14, 2019 at 10:26 AM Mr. Andrei Chichak
> > <groups at chichak.ca <mailto:groups at chichak.ca>
> <mailto:groups at chichak.ca <mailto:groups at chichak.ca>>
> > > <mailto:groups at chichak.ca <mailto:groups at chichak.ca>
> <mailto:groups at chichak.ca <mailto:groups at chichak.ca>>>> wrote:
> > >
> > > A 407 doesn’t normally have external RAM.
> > >
> > > ARMs have flash at 0 and the 407 has RAM at 0x2000 0000
> as you
> > > discussed earlier.
> > >
> > > If you want to work with external flash or RAM, you have
> to set up
> > > the FSMC or FMC to support it, but that isn’t a part of
> the dev
> > > board that Sebastian used for the BSP port.
> > >
> > > The external memory is going to be very specific to your
> board.
> > > Which board are you working with?
> > >
> > > A
> > >
> > > > On 2019-June-13, at 06:23, Christian Mauderer
> > > <christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>
> > > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>>> wrote:
> > > >
> > > > On 05/06/2019 02:55, Jython wrote:
> > > >> Hello!
> > > >>
> > > >> 2. In the normal (non-debugging) case, the linker
> > script still
> > > >> places the
> > > >>
> > > >> .text section near zero, but places the start of the
> > .data and
> > > .bss
> > > >> sections at the start location of the MPC555's
> internal
> > RAM. The
> > > >> system startup code then configures the external
> RAM just
> > > after the
> > > >> internal RAM in memory, forming one large block
> from the
> > two RAM
> > > >> devices.
> > > >>
> > > >> from https://devel.rtems.org/wiki/TBR/BSP/Ss555
> > > >>
> > > >> but i dont know how to configure the external RAM just
> > after the
> > > >> internal RAM in memory?
> > > >> hope you could give me some guide!
> > > >>
> > > >>
> > > >
> > > > Hello Jython,
> > > >
> > > > the documentation you linked is for an MPC. But your
> subject
> > line
> > > > mentions an STM32. What controller / BSP are you using?
> > > >
> > > > Best regards
> > > >
> > > > Christian Mauderer
> > > > --
> > > > --------------------------------------------
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> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>
> > > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>>
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> > --
> > --------------------------------------------
> > embedded brains GmbH
> > Herr Christian Mauderer
> > Dornierstr. 4
> > D-82178 Puchheim
> > Germany
> > email: christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> > <mailto:christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>>
> > Phone: +49-89-18 94 741 - 18
> > Fax: +49-89-18 94 741 - 08
> > PGP: Public key available on request.
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> --
> --------------------------------------------
> embedded brains GmbH
> Herr Christian Mauderer
> Dornierstr. 4
> D-82178 Puchheim
> Germany
> email: christian.mauderer at embedded-brains.de
> <mailto:christian.mauderer at embedded-brains.de>
> Phone: +49-89-18 94 741 - 18
> Fax: +49-89-18 94 741 - 08
> PGP: Public key available on request.
>
> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>
--
--------------------------------------------
embedded brains GmbH
Herr Christian Mauderer
Dornierstr. 4
D-82178 Puchheim
Germany
email: christian.mauderer at embedded-brains.de
Phone: +49-89-18 94 741 - 18
Fax: +49-89-18 94 741 - 08
PGP: Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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