Rainbow Electronics T89C51CC02 - Manual (Page 28)

28 Rev.A - May 17, 2001
Preliminary
T89C51CC02
8. Data Memory
8.1. Introduction
The T89C51CC02 provides data memory access in two different spaces:
1. The internal space mapped in three separate segments:
•
the lower 128 bytes RAM segment.
•
the upper 128 bytes RAM segment.
•
the expanded 256 bytes RAM segment (ERAM).
A fourth internal segment is available but dedicated to Special Function Registers, SFRs, (addresses 80h to FFh)
accessible by direct addressing mode.
Figure 13 shows the internal data memory spaces organization.
Figure 13. Internal Data Memory Organization
256 bytes
Upper
128 bytes
Internal RAM
Lower
128 bytes
Internal RAM
Special
Function
Registers
80h 80h
00h
FFh FFh
00h
FFh
direct addressing
addressing
7Fh
Internal ERAM
direct or indirect
indirect addressing