S-Record Information
MMDS0508OM/D
200
S-Record Information
MOTOROLA
S-Record Content
When observed, 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 two-character hexadecimal number: the first character representing
the high-order four bits and the second the low-order four bits of the byte.
Five field which comprise an S-record are shown below:
where the fields are composed as shown in
Table 15
.
Each record may be terminated with a CR/LF/NULL. Additionally, an
S-record may have an initial field to accommodate other data such as
line numbers generated by some time-sharing system.
Accuracy of transmission is ensured by the record length (byte count)
and checksum fields.
TYPE
RECORD LENGTH
ADDRESS
CODE/DATA
CHECKSUM
Table 15. S-Record Field Description
Field
Printable
Character
s
Contents
Type
2
S-record type — S0, S1, etc.
Record
Length
2
Character pair count in the record, excluding the
type and record length.
Address
4, 6, or 8
2-, 3-, or 4-byte address at which the data field is to
be loaded into memory.
Code/Data
0–2n
From 0 to n bytes of executable code, memory
loadable data, or descriptive information. For
compatibility with teletypewriter, some programs
may limit the number of bytes to as few as 28 (56
printable characters in the S-record).
Checksum
2
Least significant byte of the one’s complement of
the sum of the values represented by the pairs of
characters making up the record length, address,
and the code/data fields.
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Freescale Semiconductor, Inc.
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