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68300

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Message

Getting the RESET vector

2002-07-18 by Robert Manktelow

Hello All
We are having trouble getting our 68331 prototype board here working in
respect of the loading of the PC from memory following a reset.
We have the BDM debugger working and 16 bit wide RAM connected to CSBOOT and
we can load the ram with values via the BDM. However when the BDM debugger
releases reset the SSP is correctly loaded with the contents of address $4
but the PC is loaded with a random value, not the contents of $0.
We have just repeated this test with the manufacturers evaluation board
which also has RAM here and the PC & SSP are loaded correctly - so it looks
like a problem with our protoype board.
We are not setting the boot device memory width with hardware at reset, the
default is 16 bit wide.

Can anyone help with suggestions as to what might be going on please -
CSBOOT goes active 4 times after reset is released and the ram itself tests
out using the memory tests provided by the BDM debugger.
-
Robert Manktelow
Telspec Europe Ltd, Rochester, ME1 3QU
Phone +44 (0)1634 687 133 extension 2346

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