Rabbit 2000 - 3.2 Memory Mapping

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Designer’s

Handbook 19

5.3

Internally

defined

macros

Some

macros

used

in

the

BIOS

are

defined

internally

by

Dynamic

C

before

the

BIOS

is

compiled.

They

are

defined

using

tests

done

in

the

bootstrap

loading,

or

by

reading

vari-

ables

set

in

the

GUI.

These

are:

_FLASH_, _RAM_

-

Used

for

conditional

compilation

of

the

BIOS

to

distinguish

between

compiling

to

RAM

and

compiling

to

flash.

The

Options

|

Compile

dialog

controls

these.

_RAM_SIZE_, _FLASH_SIZE_

-

Used

to

set

the

MMU

registers

and

code

and

data

sizes

available

to

the

compiler.

The

values

given

by

these

macros

represent

the

number

of

0x1000

blocks

of

memory

available.

_BOARD_TYPE_ -

This

is

read

from

the

System

ID

block

or

defaulted

to

0x100

(the

BL1810

JackRabbit

board)

if

no

System

ID

block

is

present.

This

can

be

used

for

condi-

tional

compilation

based

on

board

type.

5.4

Modifying

the

BIOS

The

BIOS

can

be

modified

to

be

more

specific

concerning

the

user’s

configuration.

This

can

be

done

one

step

at

a

time,

making

it

easy

to

detect

any

problems.

The

source

code

for

the

Universal

BIOS

is

in

BIOS\RABBITBIOS.C.

Dynamic

C

uses

this

source

code

for

the

BIOS

by

default,

but

the

user

can

specify

another

BIOS

for

Dynamic

C

to

use

in

Options

|

Compiler

There

are

several

macros

at

the

top

of

RABBITBIOS.C

that

users

may

want

to

modify

for

boards

they

design

or

for

special

situations

involving

off-the-shelf,

Rabbit

based

boards.

USE115KBAUD

The

default

value,

1,

specifies

that

Dynamic

C

will

communicate

at

115,200

baud

with

the

target.

If

this

macro

is

set

to

zero,

Dynamic

C

will

communicate

at

57,600

baud.

The

lower

baud

rate

might

be

needed

on

some

PC’s

that

can’t

handle

115,200

baud.

If

this

is

changed

to

zero,

the

baud

rate

in

Dynamic

C

Options

|

Serial

should

be

changed

to

57,600

also.

CLOCK_DOUBLED

The

default

value

of

1

causes

the

clock

speed

to

be

doubled

if

the

crystal

speed

is

less

than

or

equal

to

12.9

MHz.

Setting

this

to

zero

means

the

clock

speed

will

not

be

doubled.

ENABLECLONING

The

default

value

of

0

disables

cloning.

Setting

this

to

1

enables

cloning

and

increases

the

code

size

of

the

BIOS

somewhat.

Table of Contents

Other manuals for Rabbit 2000

User Manual230 pages

Instruction & Reference Manual174 pages

Reference Manual120 pages

Getting Started Manual54 pages

Getting Started43 pages