52 microcontroller memory expansion

STC89C52RC is a low-power, high-performance CMOS 8-bit microcontroller produced by STC Company, with 8K bytes of system programmable Flash memory. STC89C52 uses the classic MCS-51 core, but has made many improvements to make the chip have functions that traditional 51 microcontrollers do not have. On a single chip, it has a smart 8-bit CPU and in-system programmable Flash, making the STC89C52 a highly flexible and ultra-effective solution for many embedded control application systems.

52 microcontroller memory expansion----system expansion structure

In order to reduce the number of connections and simplify the composition structure, the connections with common positives can be merged into a group of common connections, that is, the bus - a common channel for transmitting information (BUS).

The STC98C52 microcontroller has a bus-type structure, and all functional components in the chip are designed according to the bus relationship and integrated into a whole.

Three buses: address bus (AB), data bus (DB), control bus (CB).

Microcontroller system expansion mainly includes memory expansion and I/O wiring component expansion.

The memory expansion of STC89C52 microcontroller includes program memory expansion and data memory expansion.

52 microcontroller memory expansion ---- program memory expansion

There is a single type of external program memory, and read-only memory is often used. Read-only memory is referred to as ROM. Once the information in ROM is written, it cannot be changed at will, especially new content cannot be written while the program is running. ROM can still save programs after the power is turned off. After the system is powered on, the CPU can retrieve these instructions and execute them again.

52 microcontroller memory expansion----data memory expansion

STC89C52 has only 512B internal data memory, which can be used to store intermediate results and process data of program execution. The 512B data memory contains 256B of internal RAM and 256B of internal expansion RAM. The internally expanded 256B RAM is physically internal and logically external. In situations where the system requires a large amount of data buffering, the data storage capacity of the system can be expanded by externally expanding a larger-capacity static random access memory or Flash ROM. The maximum expanded capacity is 64KB, and the address is 0000H-FFFFH.