Basic questions re RTEMS and PPCbug

[Tom Armistead]

Hi David,

   Here are some pointers:

1) The RTEMS BSP for the Motorola boards requires firmware to pass in a
pointer to residual data.  The niop command under PPCBUG does not create
residual data so it won't work for booting.  To boot RTEMS, you need to
use the PPCBUG nbo command and make sure the ENV settings are set as
described in the read me file.  nbo will create residual data if the ENV
settings are correct.  FYI, R3 contains the pointer to residual data at
startup.

2) RTEMS uses 1 BAT for mapping RAM.  This limits accessible RAM to 256
megabytes.  If you are running on a board with more than that, residual
data will likely be located above the 256Meg boundary and the BSP code
which accesses it will fail.

   I haven't run RTEMS on a MVME2307 specifically but I have run it on a
MTX, MCPN750 and MCP750 and it has worked well and the MVME230x is a
similar board.  If the above doesn't get you going, I'll try to find a
MVME2307 to verify it here.  

Thanks,
Tom Armistead
  
David Hamilton wrote:
> 
> I'm inexperienced at working at the BSP/RTOS level and have some basic gaps
> in my understanding of RTEMS (I'm used to working with VxWorks).
> I have downloaded and compiled RTEMS for the MVME2307 board (closest thing
> to my MVME2400 and MVME2700 boards) and am trying to understand what I've
> got.
> 
> I seem to have a number of executables in /opt/rtems/mvme2307/samples (eg
> hello.exe etc.), but nothing looking like an OS. Is RTEMS linked (or at
> least the elements of it that are required) to the application? In that
> case, am I right in understanding that there is no shell associated with
> RTEMS.
> 
> As I said, I have MVME2400 and MVME2700 boards. I've never used PPCbug
> before, so have just started trying to get to grips with it. Anyway, I'm
> trying to see if any of the MVME2307 samples will work on either board.
> I've configured the network with NIOT and changed ENV settings according to
> README.MVME2300.
> I then load hello.exe (and others) using NIOP, and it seems to get
> transferred ok.
> I try running the programe using GO but always get an INVALID error at the
> first address.
> 
> Due to my inexperience, I'm not sure if the problem is due to
> incompatibilities between the MVME2307 bsp and my boards (although I think
> the MVME2700 is really quite close to the MVME2300 series), or whether I'm
> actually screwing up with my PPCbug commands.
> 
> It is difficult at the beginning to get a foothold.
> Any advice would be welcome,
> David

-- 
Tom Armistead