[U-Boot-Users] custom 8245 board & exceptions

"Callebaut, Benoît" benoit.callebaut at barco.com
Tue Nov 5 11:57:11 CET 2002

This is my first project with a PowerPC.
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.
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

I receive sometime a TLB miss exception

What can be the cause of that since I didn't changed anything in the memory
management code ?

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 ? 

Benoit Callebaut
Software Development Engineer
Barco | Control Rooms
Noordlaan 5, 8520 Kuurne, Belgium
Tel 	+32(0)56 36 84 28
Fax 	+32(0)56 36 86 05

mailto:benoit.callebaut at barco.com

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