Fabric OS Reference Manual

Telnet Commands 187
ramTest
Bit write/read test of SDRAMs in the switch.
Synopsis
ramTest [patternSize]
Availability admin
Description Use this command to verify the address and data bus of the SDRAMs that
serve as the 16 MB CPU memory in the switch.
The test consists of two subtests:
1. The address subtest verifies that SDRAM locations can be uniquely
accessed.
The method used is to write a unique pattern to each location in the
SDRAMs. When all are written, the data is read back from each location
and compared against the data previously written. A failure in the test
implies that the address path between the CPU and the SDRAMs is
faulty resulting in failures to program unique values.
Following is the ramp pattern used in the test:
0x57626f42, 0x57626f43, 0x57626f44, 0x57626f45, ...
2. The data subtest verifies that each cell in the SDRAMs can be
independently written and read, and that there are no short, stuck-at-1, or
stuck-at-0 faults between data cells.
The method used is to write pattern D to location N, write the
complementary pattern D to location N+1, and then read and compare
location N to location N+1. Bump the location to test: N=N+1. Repeat
the double write and read until all locations are tested with the following
nine patterns:
– 0x55555555
– 0x69696969
– 0x3c3c3c3c
– 0x1e1e1e1e
– 0x87878787