Artesyn BajaPPC-750, User Manual

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10-38 BajaPPC-750: Monitor
May 2002
or segment ( ssss ) + offset ( oooo ) = address ( aaaaa )
For addresses with fewer than 16 bits, the segment portion of the address is
unnecessary. The hex-Intel checksum is a two’s complement checksum of all data
in the record except for the initial colon (:). In other words, if you add all the data
bytes in the record, including the checksum itself, the lower eight bits of the
result will be zero if the record was received correctly.
Four types of records are used for hex-Intel format: extended address record, data
record, optional start address record, and end-of-file record. A file composed of
hex-Intel records must end with a single end-of-file record.
Extended Address Record
:02000002 sssscs
: is the record start character.
02 is the record length.
0000 is the load address field, always 0000.
02 is the record type.
ssss is the segment address field.
cs is the checksum.
The extended address record is the upper sixteen bits of the 20-bit address. The
segment value is assumed to be zero unless one of these records sets it to some-
thing else. When such a record is encountered, the value it holds is added to the
subsequent offsets until the next extended address record.
Here, the first 02 is the byte count (only the data in the ssss field are counted).
0000 is the address field; in this record the address field is meaningless, so it is
always 0000. The second 02 is the record type; in this case, an extended address
record.
cs is the checksum of all the fields except the initial colon.
EXAMPLE
:020000020020DC
In this example, the segment address is 0020
16
. This means that all subsequent
data record addresses should have 200
16
added to their addresses to determine the
absolute load address.
Data Record
:11 aaaa 00 d1d2d3...dncs
: is the record start character.
11 is the record length.
aaaa is the load address. This is the load address of the
first
data byte in the record (d1) relative to the current
segment, if any.
00 is the record type.
d1...dn are data bytes.