Jose,
--- that is how it is done, have a display output buffer, move your constant text from code memory to the buffer, add your variable data to the buffer, then display it.

..or drive it straight out to the display RAM and buffer it in there.

Incidentally, you CAN make the machine von-neumann if you want-logically and-ing PSEN and RD will do it for you.

The nice thing about Harvard architectures in a control environment is that you can't damage the program that is controlling the process. In a V-N architecture you can easily. Especially if you program in 'C'.

Steve