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Designer’s

Handbook 7

6.

The

program

enters

a

loop

where

it

receives

a

fixed

number

of

bytes

which

comprise

a

secondary

loader

program

(pilot.bin

sent

by

the

PC)

and

writes

those

bytes

to

memory

location

0x4100.

After

all

of

the

bytes

are

received,

program

execution

jumps

to

0x4100.

7.

The

secondary

loader

does

a

wrap-around

test

to

determine

how

much

RAM

is

avail-

able,

and

reads

the

flash

ID.

This

information

is

made

available

for

transmittal

to

Dynamic

C

when

requested.

8.

The

secondary

loader

now

enters

a

finite

state

machine

(FSM)

that

is

used

to

imple-

ment

the

Dynamic

C/Target

communications

protocol.

Dynamic

C

compiles

the

core

of

the

regular

BIOS

and

sends

it

to

the

target

at

address

0x00000

which

is

still

mapped

to

RAM.

Note

that

this

requires

that

the

BIOS

core

be

0x4000

or

less

in

size.

9. The

FSM

checks

the

memory

location

0x4001

(previously

set

to

zero)

after

receiving

each

byte.

When

the

compilation

and

loading

to

RAM

of

the

BIOS

is

complete,

Dynamic

C

signals

the

target

that

it

is

time

to

run

the

BIOS

by

sending

a

one

to

0x4001.

10.

The

BIOS

runs

some

initialization

code

including

setting

up

the

serial

port

for

115200

baud,

setting

up

serial

interrupts

and

starting

a

new

FSM.

11.The

BIOS

code

modifies

a

jump

instrucction

near

the

beginning

of

the

program

so

that

the

next

time

it

runs,

it

will

skip

Step

12.

12.The

BIOS

copies

itself

to

flash

at

0x80000,

and

switches

the

mapping

of

flash

and

RAM

so

that

RAM

is

at

0x80000

and

flash

is

at

0x00000.

As

soon

as

this

remapping

is

done,

the

BIOSís

execution

of

instructions

begins

happening

in

flash.

13.Dynamic

C

is

now

ready

to

compile

a

user

program.

When

the

user

compiles

his

pro-

gram

to

the

target,

it

is

first

written

to

a

file,

then

the

file

is

loaded

to

the

target

using

the

BIOS’

FSM.

The

file

is

used

as

an

intermediate

step

because

fix-ups

are

done

after

the

compilation

is

complete

and

all

unknown

addresses

are

resolved.

The

fix

ups

would

cause

extra

wear

on

the

flash

if

done

straight

to

the

flash.

14.When

the

program

is

fully

loaded,

Dynamic

C

sets

a

breakpoint

at

the

beginning

of

main

and

runs

the

program

up

to

the

breakpoint.

The

board

has

been

programmed,

and-

Dynamic

C

is

now

is

debug

mode.

15.If

the

programming

cable

is

removed

and

the

target

board

is

reset,

the

user’s

program

will

start

running

automatically

because

the

the

BIOS

will

check

the

SMODE

pins

to

determine

whether

to

run

the

user

application

or

enter

the

debug

kernel.

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