Chapter 2 Address Spaces; Overview - Samsung S3P80C5 User Manual

S3P80C5/C80C5/C80C8 ADDRESS SPACES
2
ADDRESS SPACES

OVERVIEW

The S3P80C5/C80C5/C80C8 microcontroller has two types of address space:
— Internal program memory (ROM)
— Internal register file
A 16-bit address bus supports program memory operations. A separate 8-bit register bus carries addresses and
data between the CPU and the register file.
The S3C80C5 has an internal 15,872 byte programmable ROM, the S3C80C8 has an internal 8-Kbyte
programmable ROM. An external memory interface is not implemented. The 256-byte physical RAM space is
expanded into an addressable area of 320 bytes by the use of addressing modes.
There are 312 mapped registers in the internal register file. Of these, 272 are for general-purpose use. (This
number includes a 16-byte working register common area that is used as a " scratch area" for data operations, a
256 prime register area that is used for general purpose and stack operation). Eighteen 8-bit registers are used
for CPU and system control and 22 registers are mapped peripheral control and data registers.
2-1