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Re: Running application from RAM without Redboot
- From: Gary Thomas <gary at mlbassoc dot com>
- To: Jerome Souquieres <jerome dot souquieres at kis dot fr>
- Cc: eCos Discussion <ecos-discuss at ecos dot sourceware dot org>
- Date: Fri, 22 Apr 2005 06:28:32 -0600
- Subject: Re: [ECOS] Running application from RAM without Redboot
- Organization: MLB Associates
- References: <4268EB3A.3090401@kis.fr>
On Fri, 2005-04-22 at 14:16 +0200, Jerome Souquieres wrote:
> Hi,
>
> I would like to have some advice about how to fit my specific need
> within the eCos structure.
>
> I have written a package derived from hal\mips\idt79s334a for my own
> CPU board (IDT32334 MIPS-based microprocessor). So far, so good.
> However, the way my application is launched is a bit peculiar: I have a
> ROM monitor (which is NOT Redboot and which I cannot change) that simply
> loads an hex file at a fixed address in RAM (0x80200000, should that
> matter). However, to build my application under eCos, I'm in trouble to
> choose the startup option:
> - CYG_HAL_STARTUP_ROM: is not available for my target. No more discussion.
> - CYG_HAL_STARTUP_ROMRAM: not suitable. I don't need all code to be
> copied from RAM to ROM, I don't want the SDRAM controller to be
> configured (because it is obsviously already configured at this point
> since I'm running from RAM), I don't want the exception vectors to be
> located in ROM, etc...
> - CYG_HAL_STARTUP_RAM: almost suitable,but this configuration relies on
> Redboot to provide exception vectors.
>
> For now, what I've done is tweaking the CYG_HAL_STARTUP_RAM
> configuration so that it takes control of exception vectors. This works,
> but is a bit rough because I've somewhat changed the semantics of
> CYG_HAL_STARTUP_RAM.
>
> Could an eCos architect give me a hint for a proper implementation ?
> Should I create my own CYG_HAL_STARTUP_xxx ? Should I add a sub-option ?
> Another idea ?
CYG_HAL_STARTUP_RAM is the right mode to use. All you probably need is
to make sure that CYGSEM_HAL_USE_ROM_MONITOR is disabled. In this
setup, your application should take over the hardware completely,
initializing all the exceptions and I/O
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
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