Technical data

Overview and Updates
Memory LED Codes
The memory LED codes represent continued power-on testing. If an error occurs during
this testing sequence, a hexadecimal code appears with FRU and error code information on
the monitor screen.
If the system does not enter console mode (>>>) or hex code DD is not displayed on the
LEDs, then use table 1-5 to isolate the failed FRU..
Table 1-5 Memory LED Codes
LED Display Hex Code Description
oo•ooooo
20 Machine Check
oo•oooo•
21 CELL Fill mem with test pattern data
oo•ooo•o
22 CELL Forward RD/Compare/Complement/Wr
oo•ooo••
23 CELL Reverse RD/Compare/Complement/Wr
oo•oo•oo
24 ADDR Fill mem with addresses as data
oo•oo•o•
25 Refresh test in progress
oo••oo••••o
26 Addr Read/Compare data = address
oo••oo••••••
27 BITS Fill mem with a pattern of 1's in a field
of 0's
oo••o••ooo
28 BITS Read/Compare data = pattern
oo•o•oo•
29 Reserved
oo•o•o•o
2A Reserved
oo•o•o••
2B LLSC load-locked/store-conditional tests
oo•o••oo
2C B-cache tag parity detection
oo•o••o•
2D ECC detection
oo•o•••o
2E Reserved
oo•o••••
2F Clear memory to zeros
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