Motorola M68CPU32BUG Instrukcja Użytkownika Pobierz pdf (Strona 65)

APPENDIX A

M68332BCC/D A-1 MOTOROLA

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APPENDIX A

S-RECORD INFORMATION

The S-record format for output modules was devised for the purpose of encoding programs or

data files in a printable format for transportation between computer systems. The transportation

process can thus be visually monitored and the S-records can be more easily edited.

S-RECORD CONTENT

When viewed by the user, S-records are essentially character strings made of several fields which

identify the record type, record length, memory address, code/data and checksum. Each byte of

binary data is encoded as a 2-character hexadecimal number; the first character representing the

high-order 4 bits, and the second the low-order 4 bits of the byte.

The five fields which comprise an S-record are shown below:

TYPE RECORD LENGTH

ADDRESS

CODE/DATA

CHECKSUM

Where the fields are composed as follows:

Field

Printable

Characters Contents

type 2 S-records type -- S0, S1, etc.

record

length

2 The count of the character pairs in the record, excluding type and

record length.

address 4,6,or 8 The 2-, 3-, or 4-byte address at which the data field is to be loaded

into memory.

code/data 0-n From 0 to n bytes of executable code, memory-loadable data, or

descriptive information. For compatibility with teletypewriters, some

programs may limit the number of bytes to as few as 28 (56 printable

characters in the S-record).

checksum 2 The least significant byte of the one’s complement of the sum of the

values represented by the pairs of characters making up the records

length, address, and the code/data fields.

1 2 ... 60 61 62 63 64 65 66 67 68

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Motorola M68CPU32BUG Instrukcja Użytkownika Strona 65