ST6373 datasheet(8/64 Pages) STMICROELECTRONICS

8 / 64 page

ST6373

8/64

1.3 MEMORY SPACES

The MCU operates in three different memory

spaces: Stack Space, Program Space and Data

Space.

1.3.1 Stack Space

The stack space consists of six 12 bit registers that

are used for stacking subroutine and interrupt re-

turn addresses plus the current program counter

1.3.2 Program Space

The program space is physically implemented in

the ROM and includes all the instructions that are

to be executed, as well as the data required for the

immediate addressing mode instructions, the re-

served test area and user vectors. It is addressed

thanks to the 12-bit Program Counter register (PC

to 4K bytes of Program Space. Nevertheless, the

Program Space can be extended by the addition

of 2-Kbyte memory banks as it is shown inFigure

2, in which the 16K bytes memory is described.

These banks are addressed by pointing to the

000h-7FFh locations of the Program Space thanks

to the Program Counter, and by writing the appro-

priate code in the Program ROM Page Register

(PRPR) located at address CAh in the Data

Space. Because interrupts and common subrour-

outines should be available all the time only the

lower 2K byte of the 4K program space are bank

switched while the upper 2K byte can be seen as

static space. Table 3 gives the different codes that

allows the selection of the corresponding banks.

Note that, from the memory point of view, the Page

1 and the Static Page represent the same physical

memory: it is only a different way of addressing the

same location.

Figure 3. 16K-Byte Program Space Addressing

Figure 4. Memory Addressing Diagram

Program

counter

space

0FFFh

0800h

07FFh

0000h

Static

Page

Page 1

Page 0

Page1

Static

Page

Page Page Page Page Page

1FFFh

PROGRAM SPACE

ROM

INTE RRUPT &

RESET VECTORS

ACCUMULATOR

DATA RAM

BANK SELECT

DATA ROM

WINDOW SELECT

RAM

X REGISTER

Y REGISTER

V REGISTER

W REGIS TER

DATA ROM

WIND OW

RAM / EEPROM

BANKING AREA

000h

03Fh

040h

07Fh

080h

081h

082h

083h

084h

0C0h

0FFh

0-63

DATA SPACE

0000h

0FF0h

0FFFh

PROGRAM COUNTER

STACK LEVEL 1

STACK LEVEL 2

STACK LEVEL 3

STACK LEVEL 4

STACK LEVEL 5

STACK LEVEL 6

ST6373 Folha de dados(PDF) 8 Page - STMicroelectronics

ST6373 Folha de dados(HTML) 8 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

Folha de dados Download

Ligação URL