Provided by: gpsd_2.30-1ubuntu3_i386 bug

NAME

       srec - Motorola S-record record and file format

DESCRIPTION

       Motorola S-records are a form of simple ASCII encoding for binary data.
       This format is commonly used for firmware uploads to GPSes,  industrial
       robots,  and  other  kinds  of  microcontroller-driven hardware. It has
       several convenient properties, including inspectability,  easy  editing
       with any text editor, and checksumming for verification of transmission
       across noisy serial lines.

       An S-record file consists of a sequence of  specially  formatted  ASCII
       character  strings.  An S-record will be less than or equal to 78 bytes
       in length.

       The order of S-records within a file  is  of  no  significance  and  no
       particular order may be assumed.

       The general format of an S-record follows:

              +-------------------//------------------//-----------------------+
              | type | count | address  |            data           | checksum
              |
              +-------------------//------------------//-----------------------+

       type   A  char[2]  field.  These characters describe the type of record
              (S0, S1, S2, S3, S5, S7, S8, or S9).

       count  A char[2] field. These characters when paired and interpreted as
              a  hexadecimal  value,  display the count of remaining character
              pairs in the record.

       address
              A  char[4,6,  or  8]  field.  These   characters   grouped   and
              interpreted as a hexadecimal value, display the address at which
              the data field is to be loaded into memory. The  length  of  the
              field  depends  on  the  number  of  bytes necessary to hold the
              address. A 2-byte address uses 4 characters,  a  3-byte  address
              uses 6 characters, and a 4-byte address uses 8 characters.

       data   A   char   [0-64]   field.  These  characters  when  paired  and
              interpreted as hexadecimal values represent the memory  loadable
              data or descriptive information.

       checksum
              A char[2] field. These characters when paired and interpreted as
              a hexadecimal value display the least significant  byte  of  the
              ones complement of the sum of the byte values represented by the
              pairs of characters making up the count, the  address,  and  the
              data fields.

       Each  record  is  terminated  with  a  line  feed. If any additional or
       different record terminator(s) or delay characters  are  needed  during
       transmission  to  the  target  system  it  is the responsibility of the
       transmitting program to provide them.

       There are 9 record types, as follows:

       S0     The type of record is ’S0’ (0x5330). The address field is unused
              and  will  be filled with zeros (0x0000). The header information
              within the data field is divided into the following subfields.

              1. mname is char[20] and is the module name.

              2. ver is char[2] and is the version number.

              3. rev is char[2] and is the revision number.

              4. description is char[0-36] and is a text comment.

              Each  of  the  subfields  is  composed  of  ASCII  bytes   whose
              associated   characters,   when   paired,   represent  one  byte
              hexadecimal values in the  case  of  the  version  and  revision
              numbers,  or  represent  the  hexadecimal  values  of  the ASCII
              characters comprising the module name and description.

       S1     The type of record field is ’S1’ (0x5331). The address field  is
              interpreted  as  a 2-byte address. The data field is composed of
              memory loadable data.

       S2     The type of record field is ’S2’ (0x5332). The address field  is
              interpreted  as  a 3-byte address. The data field is composed of
              memory loadable data.

       S3     The type of record field is ’S3’ (0x5333). The address field  is
              interpreted  as  a 4-byte address. The data field is composed of
              memory loadable data.

       S5     The type of record field is ’S5’ (0x5335). The address field  is
              interpreted  as a 2-byte value and contains the count of S1, S2,
              and S3 records previously transmitted. There is no data field.

       S7     The type of record field is ’S7’  (0x5337).  The  address  field
              contains  the starting execution address and is interpreted as a
              4-byte address. There is no data field.

       S8     The type of record field is ’S8’  (0x5338).  The  address  field
              contains  the starting execution address and is interpreted as a
              3-byte address. There is no data field.

       S9     The type of record field is ’S9’  (0x5339).  The  address  field
              contains  the starting execution address and is interpreted as a
              2-byte address. There is no data field.

EXAMPLE

       Shown below is a typical S-record format file.

         S00600004844521B
         S1130000285F245F2212226A000424290008237C2A
         S11300100002000800082629001853812341001813
         S113002041E900084E42234300182342000824A952
         S107003000144ED492
         S5030004F8
         S9030000FC

       The file consists of one S0 record, four S1 records, one S5 record  and
       an S9 record.

       The S0 record is comprised as follows:

       ·  S0 S-record type S0, indicating it is a header record.

       ·  06  Hexadecimal  06 (decimal 6), indicating that six character pairs
          (or ASCII bytes) follow.

       ·  00 00 Four character 2-byte address field, zeroes in this example.

       ·  48 44 52 ASCII H, D, and R - "HDR".

       ·  1B The checksum.

       The first S1 record is comprised as follows:

       ·  S1 S-record type S1, indicating it is a data record to be loaded  at
          a 2-byte address.

       ·  13  Hexadecimal  13 (decimal 19), indicating that nineteen character
          pairs, representing a 2 byte address, 16 bytes of binary data, and a
          1 byte checksum, follow.

       ·  00  00  Four  character  2-byte  address  field; hexidecimal address
          0x0000, where the data which follows is to be loaded.

       ·  28 5F 24 5F 22 12 22 6A 00 04 24 29 00 08 23  7C  Sixteen  character
          pairs representing the actual binary data.

       ·  2A The checksum.

       The  second and third S1 records each contain 0x13 (19) character pairs
       and are ended with checksums of 13 and 52, respectively. The fourth  S1
       record contains 07 character pairs and has a checksum of 92.

       The S5 record is comprised as follows:

       ·  S5  S-record type S5, indicating it is a count record indicating the
          number of S1 records

       ·  03 Hexadecimal 03 (decimal 3), indicating that three character pairs
          follow.

       ·  00  04  Hexadecimal 0004 (decimal 4), indicating that there are four
          data records previous to this record.

       ·  F8 The checksum.

       The S9 record is comprised as follows:

       ·  S9 S-record type S9, indicating it is a termination record.

       ·  03 Hexadecimal 03 (decimal 3), indicating that three character pairs
          follow.

       ·  00  00  The  address field, hexadecimal 0 (decimal 0) indicating the
          starting execution address.

       ·  FC The checksum.

NOTES

       ·  There isn’t any evidence that Motorola ever made use of  the  header
          information  within  the  data  field of the S0 record, as described
          above. This may have been used by some third party vendors.

       ·  The Unix manual page on S-records is the only place that  a  78-byte
          limit  on  total  record  length  or 64-byte limit on data length is
          documented. These values shouldn’t be trusted for the general  case.

       ·  The  count  field  can  have  values in the range of 0x3 (2 bytes of
          address + 1 byte checksum = 3, a not very useful  record)  to  0xff;
          this  is the count of remaining character pairs, including checksum.

       ·  If you write code to convert S-Records,  you  should  always  assume
          that  a  record can be as long as 514 (decimal) characters in length
          (255 * 2 = 510, plus 4 characters for the type  and  count  fields),
          plus any terminating character(s). That is, in establishing an input
          buffer in C, you would declare it to be an array of 515 chars,  thus
          leaving room for the terminating null character.

SEE ALSO

        gpsd(8), xgps(1), libgps(3), libgpsd(3), gpsfake(1). gpsprof(1).

AUTHOR

       From  an  anonymous web page, itself claiming to have been derived from
       an old Unix manual page. Now maintained by the the GPSD project.  There
       is a project page for gpsd  here: http://gpsd.berlios.de/.

                                                                       SREC(5)