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Diagnostics
AM700 Audio Measurement Set Service Manual
6–37
f. If any bad data lines were found, jump back to the startup code.
If there is an access error on this step, it will likely be caused by a write
access; it is also possible to get parity induced access errors here, if the
Board Program Register fails to mask them.
6. Test the DRAM address bus.
a. Encode the 8-bit boot step number into the USP LSByte.
b. Write “6” on the diagnostic LED display.
c. Copy all BootInfo info from start of DRAM to a region that should not
get corrupted if the Address Bus is working, for later restoration.
The storage region is from 0x30000204 to 0x300003fc.
This will work as long as the BootInfo structure is less than or equal to
504 bytes in length.
d. Zero each DRAM location whose address has one address line high and
the others low, or one address line low and the others high:
0x30000004, 30000008, 30000010, 30000020, 30000040, 30000080,
0x30000100, 30000200, 30000400, 30000800, 30001000, 30002000,
0x30004000, 30008000, 30010000, 30020000, 30040000, 30080000,
0x30100000, 30200000, 30400000 (stop here if 8 Meg)
( 0x30800000 if 16Meg ), (0x31000000 if 32 Meg)
0x3XXffff8, 3XXffff4, 3XXfffec, 3XXfffdc, 3XXfffbc, 3XXfff7c
0x3XXffefc, 3XXffdfc, 3XXffbfc, 3XXff7fc, 3XXfeffc, 3XXfdffc,
0x3XXfbffc, 3XXf7ffc, 3XXefffc, 3XXdfffc, 3XXbfffc, 3XX7fffc
If 8 Meg:
XX is 07
0x306ffffc, 305ffffc, 303ffffc.
If 16 Meg:
XX is 0f
0x300efffc, 30dffffc, 30bffffc, 307ffffc.
If 32 Meg:
XX is 1f
0x31effffc, 31dffffc, 31bffffc, 317ffffc, 30fffffc.