Motorola S-records Motorola S-records are a way of representing binary memory images in an ASCII form, which is a more convenient format for transfer between some computer systems. Binary data is transferred by sending fields of the following form: Field S Type Length Address Data Checksum Number of 1 1 2 4,6 or 8 varies 2 Characters The fields are used as follows: S The letter ‘S’ (upper case) signals the start of the record type A digit between 0 and 9 which defines the record type, as described below: 0: A header record (ignored by 1616/OS ) 1: A data record with a 2-byte address field 2 A data record with a 3-byte address field 3: A data record with a 4-byte address field 4:
Not allowed 5: The number of type 1, 2 and 3 records in a group of S-records. Ignored by 1616/OS 6: Not allowed 7: Terminating record for S1 records 8: Terminating record for S2 records 9: Terminating record for S3 records length The number of character pairs in the address, data and checksum fields. This field is a two character quantity (a hexadecimal byte) address This is the address at which the S-record loads into memory in the target system. It is a 2, 3 or 4 byte address (4, 6 or 8 hex characters), depending upon whether it is part of an S1, an S2 or an S3 type record. data This is the actual data to be loaded. It is a series of hexadecimal bytes.
checksum This is the checksum of the length, address and the data fields. It is calculated by adding together the values of all the bytes received in these fields, inverting (taking the one’s complement of) the result and transmitting the least significant byte of the result as two ASCII hexadecimal digits. Page 102 User Tutorial Manual Appendix A