3980xpi Users Manual - Data I/O Corporation

Fairchild Fairbug, Code 80
Translation Formats
In the Fairbug format, input and output requirements are identical; both have
8-byte records and identical control characters. Figure 5-8 shows a Fairbug
data file. A file begins with a 5-character prefix and ends with a 1-character
suffix. The start-of-file character is an S, followed by the address of the first
data byte. Each data byte is represented by 2 hexadecimal characters. The
programmer will ignore all characters received prior to the first S.
Note: Address specification is optional in this format; a record with
no address directly follows the previous record.
Each data record begins with an X and always contains 8 data bytes. A 1-digit
hexadecimal checksum follows the data in each data record. The checksum
represents, in hexadecimal notation, the sum of the binary equivalents of the
16 digits in the record; the half carry from the fourth bit is ignored.
The programmer ignores any character (except for address characters and the
asterisk character, which terminates the data transfer) between a checksum
and the start character of the next data record. This space can be used for
comments.
Figure 5-8. Fairchild Fairbug (example)
Start Record
S = Start Character
0000 = Address Field
S0000
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
XFFFFFFFFFFFFFFFFC
*
End-of-File Record
Data Records
X = Data Record Start Character
FF = 2 Hex Characters (1 Byte)
C = Checksum. 1-digit summation
of data in record
The last record consists of an asterisk only, which indicates the end of file.
3980xpi/3980/3900/2900 User Manual 5-17
0080-2