The purpose of this document is to give some guidelines about how to write and execute assembly code in RAM with the ST7 8-bit Microcontroller. The memory mapping in the ST72251 is shown in the following figure. The ST7 RAM and ROM locations are addressed and read in the same way. For the ST7 core fetching and decoding instructions located either in RAM or ROM, take the same time, there is no limitation executing code in RAM.