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6–38
AM700 Audio Measurement Set Service Manual
e. Write 0xFFFFFFFF to the first and last DRAM location.
0x30000000 is first
0x3XXffffc is last, where:
XX is 07 if 8 Meg
XX is 0f if 16 Meg
XX is 1f if 32 Meg
f. Check each of the zeroed locations for non-zero content. A non-zero
content indicates a misdirected write.
g. Indicate bad address lines by showing “A” and then the hex char
“0”–”F” (0–31) on the diagnostic LED display.
h. After all lines have been tested, if any of address A2 through A20 failed,
jump back to the startup code.
i. Otherwise, restore BootInfo and continue testing.
7. If not skipping, test the boot RAM, the malloc pool RAM, and the
“FLASH COPY” RAM.
a. Encode the 8-bit boot step number into the USP LSByte.
b. Write “7” on the diagnostic LED display.
c. Copy the first two long words of DRAM into registers.
NOTE. Parity error detection must be disabled during the previous Copy, because
locations which may not have been written yet are being read.
d. Enable Parity Error Exceptions via the Board Program Register (BPR)
(unless a 32-bit DRAM is being used).
e. Using registers only:
Write each long word’s address into its own location.
Read back and verify each, aborting test if error occurs.
Write the inverse of each long word’s address into its own location.
Read back and verify each, aborting test if error occurs.
f. Disable Parity Error Exceptions through the BPR (unless a 32-bit
DRAM is being used).
g. If an error occurred during read back, flash “7” on the Diagnostic LED
display –several– times and jump to the startup code.
h. Otherwise, restore the first two long words in the DRAM and continue
testing.