Motorola M68CPU32BUG Manuale Utente Scaricare il pdf (Pagina 12)

• Read Appendix 3 in its entirety.

• Generate the S-record ﬁle which is to be downloaded to the microcontroller board.

Part 1: Machine code generation

The assembly program for this experiment is in Appendix 1.

Generate the machine code that corresponds to this program into machine code in hexa-

decimal format.

Part 2: S-Record creation

Generate the S-record ﬁle for the machine code created in Part 1.

In order to generate the S-record ﬁle a thorough understanding of the S-record format is

needed. Refer to the Appendix 3 for the details of the S-record format.

The following example illustrates the steps for the generation of an S-record. Note that

the spaces between the numbers in the steps below are for readability and should not be

there in the actual S-record ﬁle.

Example program:

ORG $4000

MOVE.L #$1234,D0

MOVE.L D0,D1

Step 1: Generate the machine code in byte code format:

20 3C 00 00 12 34

22 00

Step 2: Break the code into blocks. For this example, 2 blocks will be used, even though

one would be sufﬁcient.

Block 1: 20 3C 00 00 12 34

Block 2: 22 00

Step 3: Append to the left the starting address, or the address location where the blocks

will be stored. Address $4000 will be used to store this program as speciﬁed by the ORG

command in the code:

40 00 20 3C 00 00 12 23

40 06 22 00

Step 4: Count the character pairs (bytes) of each block in step 3. Add 1 to this number

and append the ﬁnal result to the left of each block.

09 40 00 20 3C 00 00 12 34

05 40 06 22 00

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 34 35

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Motorola M68CPU32BUG Manuale Utente Pagina 12