7 - 15
7 Serial Communications
NX-series Communications Interface Units User’s Manual (W540)
7-4 Examples of Communications between CPU Unit or Communications Master and CIF Unit
7
7-4-1 Example of Sending Data
5 Output
response
for
UVWXY
Z
• The communications master receives the
in
put notification data given on the right.
• The communications master knows that
UVWXYZ was normall
y received by the
CIF Unit because the Output SID
Response in the input notification data is
01 hex.
The CIF Unit inputs the following input noti-
fication data to tell the CPU Unit or com-
munications master that UVWXYZ was
received normally.
6 Sending
UVWXY
Z
--- The CIF Unit sends UVWXYZ to the serial
line
.
7 --
- • The communications master outputs the
followin
g output notification data.
• There is no new output data.
---
8 Confirm-
ing send-
ing of
UVWXY
Z
• The communications master receives the
in
put
notification data given on the right.
• The communications master knows that
the CIF Unit
sent UVWXYZ to the serial
line because the Send Completed Toggle
Bit in the Port Status in the input notifica-
tion data changed.
The CIF Unit inputs the following input noti-
fication data and tells the CPU Unit or com-
munications master that UVWXYZ was
sent
to the serial
line.
*1. : Output notification data is output from the CPU Unit or communications master to the CIF Unit.
: Input notification data is input from the CIF Unit to the CPU Unit or communications master.
*2. The CIF Unit sends the output data to the serial line immediately after receiving it from the CPU Unit or communications
master only when transmission buffering is disabled. If transmission buffering is enabled, all of the output data is sent at
the same time after it has been received.
Step Process
CPU Unit or communications master
processing
Communi-
cations
direction
*1
CIF Unit processing
There is data in
the send buffer.
Set the Output
SID.
0011 hex
00 hex
02 hex
0000 hex
0000 hex
0000 hex
00 hex,
00 hex,
00 hex,
00 hex
Input Data 01
Port Status
Input SID
Output SID
Response
Input Data Type
Input Sub Info
Input Data Length
02 hex
00 hex
0000 hex
0000 hex
0000 hex
00 hex,
00 hex,
00 hex,
00 hex
Not incremented.
There is no
send data.
Output SID
Input SID
Response
Output Data
Type
Output Sub Info
Output Data
Length
Output Data 01
The Send
Completed
Toggle Bit
changes.
No change
0012 hex
00 hex
02 hex
0000 hex
0000 hex
0000 hex
00 hex,
00 hex,
00 hex,
00 hex
Input Data 01
Port Status
Input SID
Output SID
Response
Input Data Type
Input Sub Info
Input Data Length
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