Rainbow-electronics T89C51CC02 Manual de usuario descargar pdf (Pagina 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

00h

FFh

direct addressing

addressing

7Fh

Internal ERAM

direct or indirect

indirect addressing

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Rainbow-electronics T89C51CC02 Manual de usuario Pagina 28