Altera High-Speed Development Kit, Stratix GX Edition - Manual (Page 119)

Altera Corporation Quartus II Version 3.0 7–37
Diagnostic Test Details Nios Designs
This design has 2 dual-port RAM modules controlled by the Nios
processor. The command FIFO buffer handles all of the command
sequences for the test state machine. The data RAM holds the data values
used to write and read the memory. The DDR state machine reads the
command sequences and the data values and generates the proper
signals to control the DDR IP core. The DDR IP takes advantage of the
built-in features of the Stratix GX device to implement the DDR interface
at 200 MHz. These features include the on-chip termination and the
ability to run the I/O banks at 2.5 volts.
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For more information on the DDR SDRAM Controller MegaCore
function, see the Altera web site.
The DDR test uses a C program that controls the commands and data
patterns used during the memory test. The memory test comprises four
tests that exercise reads and writes in various burst sizes.
■ The first test, long burst test, writes 100 back-to-back bursts of eight
words followed by reads of 100 back-to-back bursts of eight words.
This test can use two different data patterns. One is an increment fs
pattern and the other is an all 1s followed by all 0s pattern known as
the worst-case pattern. For this test, the worst-case pattern was used.
■ The second test, address bus walking 1s test, writes to the addresses
0x00000001, 0x00000010, 0x00000100, and so forth. After these
addresses are written, they are read back and compared. This test
uses an increment aa55 pattern.
■ The third test, variable burst length test, writes small bursts (burst
sizes of 2, 4, and 8) of varying data patterns then reads and compares.
This test uses many data patterns, such as all es, increment fs, worst
case, and increment aa55.
■ The last test, full DIMM write then read test, writes the whole DIMM
and then reads the whole DIMM and compares. For this test, the
worst-case pattern was used.
All of these tests are run 20,000 times. If a mismatch is found in any of the
tests, the processor reports the error to the shell. The test repeats until you
stop it.