S3C72P9 datasheet(13/225 Pages) SAMSUNG

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S3C72P9/P72P9 (Preliminary Spec)

ADDRESS SPACES

2-1

ADDRESS SPACES

PROGRAM MEMORY (ROM)

OVERVIEW

ROM maps for S3C72P9 devices are mask programmable at the factory. In its standard configuration, the

device's 32,768

× 8-bit program memory has three areas that are directly addressable by the program counter

(PC):

— 16-byte area for vector addresses

— 96-byte instruction reference area

— 16-byte general-purpose area

— 32,640-byte general-purpose area

General-purpose Program Memory

Two program memory areas are allocated for general-purpose use: One area is 16 bytes in size and the other is

32,640 bytes.

Vector Addresses

A 16-byte vector address area is used to store the vector addresses required to execute system resets and

interrupts. Start addresses for interrupt service routines are stored in this area, along with the values of the

enable memory bank (EMB) and enable register bank (ERB) flags that are used to set their initial value for the

corresponding service routines. The 16-byte area can be used alternately as general-purpose ROM.

REF Instructions

Locations 0020H–007FH are used as a reference area (look-up table) for 1-byte REF instructions. The REF

instruction reduces the byte size of instruction operands. REF can reference one 2-byte instruction, two 1-byte

instructions, and one 3-byte instructions which are stored in the look-up table. Unused look-up table addresses

can be used as general-purpose ROM.

Table 2-1. Program Memory Address Ranges

ROM Area Function

Address Ranges

Area Size (in Bytes)

Vector address area

0000H–000FH

General-purpose program memory

0010H–001FH

REF instruction look-up table area

0020H–007FH

General-purpose program memory

0080H–7FFFH

32,640

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