Intel MCS48 User Manual page 457

B.
Paper
Tape Format
The
paper tape
which
should be used
is
1"
wide paper using 7 or 8-bit
ASCII code (such
as a
Model 33
ASR
Teletype
pro-
duces).
The
three
paper tape formats
which should be sent are described in
Sections
B1 through
B3.
B1. Intellec
Hex
Paper
Tape Format
In
the
Intel Intellec
Hex Format,
a
data field
can contain
either
8
or
4-bit data.
Two
ASCII
hexadecimal
characters
must
be
used to represent
both
8 and
4-bit data.
In
the case of
4-bit data,
only
one
of the characters
is
meaningful
and must be
specified
on
the
Intel
PROM/ROM
Order Form.
Preceding the
first
data field
and following the
last
data
field
there
must be
a leader/trailer
length of
at
least
25
null
charac-
ters.
Comments
(except for
a
colon)
may
be placed
on
the tape leader.
The format
described
below
is
readily
generated by the
Intel
Intellec
Microcomputer Development System
or
by systems
programmed
by
the
user.
1.
RECORD
MARK
FIELD: Frame
The ASCII
code for
a
colon
(:) is
used to
signal
the
start
of a record.
2.
RECORD LENGTH
FIELD: Frames
1
and
2
The number
of
data bytes
in
the record
is
representated
by two ASCII hexadecimal
digits in this field.
The
high-order
digit
is
in
frame
1.
The
maximum
number of data bytes
in a
record
is
255 (FF
in
hexadecimal).
An
end-of-file
record
contains
two ASCII
zeros
in this field.
3.
LOAD ADDRESS
FIELD:
Frames
3-6
The
four
ASCII hexadecimal
digits
in
frames
3-6
give
the address at
which
the data
is
loaded.
The
high-order
digit
is
in
frame
3,
the lower-order
digit in
frame
6.
The
first
data
byte
is
stored
in
the location indicated
by
the load address;
successive bytes are
stored
in
successive
memory
locations.
This
field in
an
end-of-file
record contains zeros or the
start-
ing
address of the
program.
4.
RECORD
TYPE
FIELD:
Frames
7
and 8
The two ASCII hexadecimal
digits in
this field
specify the record type.
The
high-order
digit
is
in
frame
7.
All
data
records are
type
0; end-of-file
records
are
type
1.
Other
possible values for this field
are reserved for
future expansion.
5.
DATA
FIELD:
Frames 9
to
9+2*(record length)~1
A
data byte
is
represented by
two frames containing the ASCII
characters
0—9
or
A—
F,
which
represent
a
hexadecimal
value
between and
FF
(0
and
255
decimal).
The
high-order
digit
is
in
the
first
frame
of
each
pair.
If
the data
is
4-bit,
then either
the high or low-order
digit
represents the data
and the other
digit o* the pair
may
be
any ASCII hexadecimal
digit.
There
are
no
data bytes
in
an end-of-file record.
A2-7