68300

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

>CSBOOT goes active 4 times after reset is released ....

Sounds like the reset address at 0 in your ROM is outside the CSBOOT
decoded range.

Dimiter

--------------------------------------------------------------------
Dimiter Popoff
Transgalactic Instruments
http://transgalactic.freeyellow.com

Just in case you really meant what you typed...  The initial SSP is at $0
(not $4) and the initial PC is at $4 (not $0).  Maybe that little mix-up is
adding to your troubles.

Jeff





"Robert Manktelow" <robert.manktelow@...> on 07/18/2002 09:15:03
AM

Please respond to 68300@yahoogroups.com

To:    "Yahoo 68300 group" <68300@yahoogroups.com>
cc:

Subject:    [68300] Getting the RESET vector


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



---------------------------------------------------
To unsubscribe from this group, send an email to:
68300-unsubscribe@yahoogroups.com

To learn more about Motorola Microcontrollers, please visit
http://www.motorola.com/mcu



Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/