PTS - Improve DDR memory test program
Issue of test07 (DDR) of the PTS of the SPEC board.
We were running test07 repeatedly in some boards of an old batch that we
made. There were some boards that failed the test about one time out of
ten executions. However, there are some boards which never fail.
This induces me to think that a single execution of test07 is not a good
guarantee that the DDR is working properly. BGA packages can show
intermittent failures of these packages that are not unusual when there
is a soldering problem.
Maybe it would be desirable to improve the test07 testing algorithm in the future or at least modify it to perform several repetitions (perhaps making it a bit more efficient, because now it is quite slow considering the limited number of read/write operations that it carries out).