ST6285BQ6 View Datasheet(PDF) - STMicroelectronics

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ST6285BQ6

8-BIT OTP/EPROM MCU WITH LCD DRIVER, EEPROM AND A/D CONVERTER

STMicroelectronics 

ST62T85B/E85B

1.3 MEMORY MAP

1.3.1 Introduction

The MCU operates in three separate memory

spaces: Program space, Data space, and Stack

space. Operation in these three memory spaces is

described in the following paragraphs.

Briefly, Program space contains user program

code in Program memory and user vectors; Data

space contains user data in RAM and in Program

memory, and Stack space accommodates six lev-

els of stack for subroutine and interrupt service

routine nesting.

common (STATIC) 2K page is available all the

time for interrupt vectors and common subrou-

tines, independently of the PRPR register content.

This “STATIC” page is directly addressed in the

0800h-0FFFh by the MSB of the Program Counter

register PC 11. Note this page can also be ad-

dressed in the 000-7FFh range. It is two different

ways of addressing the same physical memory.

Jump from a dynamic page to another dynamic

page is achieved by jumping back to the static

page, changing contents of PRPR and then jump-

ing to the new dynamic page.

1.3.2 Program Space

Program Space comprises the instructions to be

Figure 3. 8Kbytes Program Space Addressing

executed, the data required for immediate ad-

ROM SPACE

dressing mode instructions, the reserved factory

test area and the user vectors. Program Space is

) addressed via the 12-bit Program Counter register

t(s (PC register).

c Program Space is organised in four 2K pages.

u Three of them are addressed in the 000h-7FFh lo-

d cations of the Program Space by the Program

ro Counter and by writing the appropriate code in the

Program ROM Page Register (PRPR register). A

P Figure 4. Memory Addressing Diagram

lete PROGRAM SPACE

Obso 0000h

Product(s) - PROGRAM

ObsoleteMEMORY

0-63

PC

SPACE 0000h

000h

7FFh

Page 0

800h

FFFh

Page 1

Static

Page

Page 1

Static

Page

Page 2

1FFFh

Page 3

DATA SPACE

000h

RAM / EEPROM

BANKING AREA

03Fh

040h

07Fh

080h

081h

082h

083h

084h

DATA READ-ONLY

MEMORY WINDOW

X REGISTER

Y REGISTER

V REGISTER

W REGISTER

RAM

0FF0h

0FFFh

INTERRUPT &

RESET VECTORS

0C0h

0FFh

DATA READ-ONLY

MEMORY

WINDOW SELECT

DATA RAM

BANK SELECT

ACCUMULATOR

VR01568

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