8.
COMMNICATIONS USING DEDICATED PROTOCOLS
MELSEGA
8.9
Buffer Memory Read and
Write
This function is used to read from and write to the
AJ71C24
buffer memory.
When this function is used, communications between the computer and
AJ71 C24
commences immediately when the computer sends a read or write
request, without waiting for the
PC CPU
END processing. Therefore, the
time
T1,
described
in
Section
8.5,
is always equal to zero. The
PC CPU
carries out buffer memory read and write using
TO
and
FROM
instructions.
The method for specifying the control protocol, meanings, and examples for
carrying
out
this function are shown below.
8.9.1
Commands and
buffer
memory
(1)
ACPU
common commands
Note
:
o
..........
Executable
(2)
Buffer memory
Buffer memory addresses are
OH
to
7FFH
see (see Section
34,
One address consists
of
1
word
(16
bits).
Read and write are both executed
in
word units, regardless of the
word/byte unit setting.
POINTS
1
(1)
When accessing the user area
in
buffer memory simultaneously by
using this function
in
the no-protocol mode (see Section
9)
or the
bidirectional mode (see Section
lo),
the buffer memory address in the
following area should not be designated by the command described
in item
(1)
in
Section
8.9.1.
0
No-protocol mode send area (or bidirectional mode send area)
0
No-protocol mode receive area (or bidirectional mode receive area:
0
On-demand area
(2)
Buffer addresses
100H
to
11
FH
comprise the special applications
area. The
AJ71C24
will not operate correctly
if
any operations other
than those described
in
the following sections are executed.
8-
67
.
.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
To Next Page
Loading...
