Hi Mahmood,

Here are my thoughts....

I understand this test is a part of self test routine which you would like to execute during start up. You can write routines for other tests (timers, ADC, etc.) in C except for the internal RAM test and you have to do the RAM test before (so called) "C" takes over. That's why people are suggesting to put it in cstartup.a51 and assembly language programming knowledge comes handy here. This limitation is due to the 8052's architecture.

I have written this on the assumption that you are using normal 8052 and not the derivatives that have in built XRAM and you want to test this XRAM.

If you want to do the RAM test (for a reason unknown to me) while the CPU is running, you can do it with a routine done in assembly and embedding it in your C programme. This requires a good knowledge of assembly language and a page or two of external RAM available in your system. It is quite complicated.