Re: [openrisc] need help with boot strategy

[Marko Mlinar <markom@opencores.org>]

On Monday 09 June 2003 12:56, Patrick Pelgrims wrote:
> Marko Mlinar wrote:
> >>3) Make a hardware bootstrapper which can hold the CPU in reset, load the
> >>CPU RAM from an external source and release the reset line.
> >>
> >>This may at least get you thinking on what is appropriate for your
> >>platform.
> >
> >It goes the same as for all other platforms.
> >
> >I use gdb to load an application into RAM, or load the application into
> > flash, which then copies .data to RAM and executes itself from RAM/flash.
> > See linker (.ld) scripts in e.g. or1ksim/testbench for latter loaders.
> > First one is trivial anyway.
>
> At the end, in an embedded application there is no gdb :-).
> So option 3 would be nice, if more than one 'external' option could be
> provided by e.g. jumper settings or flash settings.
> 1) Downloading via the serial port (a lot of processors have this
> option: Leon, MC68VZ328 ...AVR..).
>      The first firmware or bootcode could be loaded internal/external
> and on board flash could be programmed.
>      JTAG can also be used, but commercial JTAG-tools and software are
> expensive

Note that gdb works with the so called JP1 protocol, which is compatible with 
JTAG and it requires just parallel cable, e.g. cable for programming Xilinx 
devices.
Once I wrote an application which is loaded into RAM and it decompresses 
itself into flash this way. You could also use ORPMon and load application 
via TFTP if you have ethernet on your system. Serial is a bit slow.

Marko


--
To unsubscribe from openrisc mailing list please visit http://www.opencores.org/mailinglists.shtml