[U-Boot-Users] custom 8245 board & exceptions
wd at denx.de
Tue Nov 5 12:51:03 CET 2002
in message <81A66F72DCACD511B0600002A551BFCB4E9CA3 at kuumex05.barco.com> you wrote:
> Our board is loosely based on the Sandpoint 8245 Unity board. The main
> difference is that it contains also a DSP and FPGA. The PowerPC related part
> is only composed of the MPC8245 running as PCI agent , 16MB of SDRAM, 2
> Flash ("primary" of 512KB and second one of 8MB) and the PCI bus (no serial
> port->no console)
> I can Flash PPCBOOT with the BDI and use he SDRAM.
> I modified the putc and puts functions to write in a circular buffer located
> in RAM.
This is NOT a good idea. Console I/O is iused a long time before the
RAM gets initialized, so you are provoking undefined behaviour.
> The problem is that that doesn't always work. I receive a "data storage
> interrupt" coming from the function initdram.
> Note that the circular buffer is initialized just after initdram and that
> the position of the buffer and its data structure is hard wired in the
But console I/O is used long before that!
> I received before also a decrementer interrupt and I disabled the bit for
> it. I don't understand clearly the usefulness of this. Does it work like a
> watchdog ?
I suggest you get yourself a BDI2000, which allows for good debugging
features, but also for a remote console feature which might be _very_
handy in your situation.
Ummm... and think about some form of punishment for the guys who
designed your hardware. A board without a serial port is very
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd at denx.de
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