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       srec_signetics - Signetics file format


       The Signetics file format is not often used.  The major disadvantage in
       modern applications is that the addressing range  is  limited  to  only

       All  data  lines  are  called  records,  and  each  record contains the
       following 5 fields:

                           |: | aaaa | cc | as | dd | ss |
       The field are defined-as-follows:--+----+----+----+

       :       Every record starts with this identifier.

       aaaa    The address field.  A four digit (2 byte)  number  representing
               the first address to be used by this record.

       cc      The  byte‐count.   A  two  digit  value  (1 byte), counting the
               actual data bytes in the record.

       as      Address checksum.  Covers 2 address bytes and the byte count.

       dd      The actual data of this record.  There can be  1  to  255  data
               bytes per record (see cc)

       ss      Data  Checksum.  Covers only all the data bytes of this record.

   Record Begin
       Every record begins with a colon  “:[rq]  character.   Records  contain
       only  ASCII characters.  No spaces or tabs are allowed in a record.  In
       fact, apart from the 1st colon, no other characters than 0..9 and  A..F
       are  allowed  in  a  record.  Interpretation of a record should be case
       less, it does not matter if you use a..f or A..F.

       Unfortunately the colon was  chosen  for  the  Signetics  file  format,
       similar  to  the Intel format (see srec_intel(5) for more information).
       However, SRecord is able to automatically detect the dofference between
       the two format, when you use the -Guess format specifier.

   Address Field
       This  is  the address where the first data byte of the record should be
       stored.  After storing that data byte, the address is incremented by  1
       to  point  to the address for the next data byte of the record.  And so
       on, until all data bytes are stored.  The address is represented by a 4
       digit hex number (2 bytes), with the MSD first.  The order of addresses
       in the records of a file is not important.  The file may  also  contain
       address gaps, to skip a portion of unused memory.

   Byte Count
       The  byte  count cc counts the actual data bytes in the current record.
       Usually records have 32 data bytes, but any number between 1 and 255 is

       A value of 0x00 for cc indicates the end of the file.  In this case not
       even the address checksum will  follow!   The  record  (and  file)  are
       terminated immediately.

       It  is not recommended to send too many data bytes in a record for that
       may increase the transmission time  in  case  of  errors.   Also  avoid
       sending  only a few data bytes per record, because the address overhead
       will be too heavy in comparison to the payload.

   Address Checksum
       This is not really a checksum anymore, it looks more like a  CRC.   The
       checksum  can  not  only  detect errors in the values of the bytes, but
       also bytes out of order can be detected.

       The checksum is calculated by this algorithm:
              checksum = 0
              for i = 1 to 3
                checksum = checkum XOR byte
                ROL checksum
              next i
       For the Address Checksum we only need 2 Address bytes and 1 Byte  Count
       byte to be added.  That’s why we count to 3 in the loop.  Every byte is
       XORed with the previous result.  Then the intermediate result is rolled
       left (carry rolls back into b0).

       This results in a very reliable checksum, and that for only 3 bytes!

       The  last  record  of  the file does not contain any checksums!  So the
       file ends right after the Byte Count of 0.

   Data Field
       The payload of the record is formed by the Data field.  The  number  of
       data  bytes expected is given by the Byte Count field.  The last record
       of the file may not contain a Data field.

   Data Checksum
       This checksum uses the same algorithm as used for the Address Checksum.
       This  time  we  calculate the checksum with only the data bytes of this
              checksum = 0
              for i = 1 to cc
                checksum = checksum XOR byte
                ROL checksum
              next i
       Note that we count to the Byte Count cc this time.

   Size Multiplier
       In general, binary data will expand in sized by approximately 2.4 times
       when represented with this format.


       Here is an example Signetics file
       In  the  example above you can see a piece of code in Signetics format.
       The first 3 lines have 16 bytes of data each, which can be seen by  the
       byte  count.  The 4th line has only 13 bytes, because the program is at
       it’s end there.

       Notice that the last record of the file contains no data bytes, and not
       even an Address Checksum.



       This man page was taken from the above Web page.  It was written by San
       Bergmans <>