stm32 external SRAM

Jython googcheng at gmail.com
Mon Jun 17 06:32:24 UTC 2019


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> 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>> 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>>> 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>>> 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>>
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> --
> --------------------------------------------
> 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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