Hi I need to develop a source code for testing RAM for 89c51. can any one help me how to develop source code.
actually i need to monitor the health of my 89c51 continuosly. Since my project has to meet Safety Integration level 4 and industrial standards.
You need a thorough understanding of how memory systems work, and the possible failure mechanisms, to be able to write an effective memory test.
Read this article for further details:
www.embedded.com/.../0007feat1.htm
As Erik says, you also need to consider whether any tests that the processor runs can be valid if the processor itself is faulty!
This has been discussed here before ad nauseam - search for "memory test", "RAM test", etc...