Damjan,

Review the previously mentioned thread.

DRAM is easily put in place on an 8051 you have some decisions to make in the implementation.

You can avoid using ras/cas mux's if you are using it as data store where you manipulate bits to access the data.

If you want to use it as standard fast access ram you will implement ras/cas addrs. mux, generate the ras/cas access strobes, generate high address lines to access the memory in banks and generate refresh. This is not as hard as it may sound.

regards,
p