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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
7-4-4 Example for a Parity Error during Data Reception
This section gives an example of a parity error in the third character when a 6-byte string (123456) was
received.
Here, we will assume that the input notification data and output notific
ation data are in the following sta-
tus before the data is received.
Input Notification Data
7 •Confirm-
ing
sending
of
ABCD
•
Notifica-
tion of
end
de
tec-
tion
• The communications master receives
th
e inp
ut notification data given on the
right.
• The communications master knows
th
at
the CIF Unit sent ABCD to the
serial line because the Send Com-
pleted Toggle Bit in the Port Status in
th
e input notification data changed.
• The communications master knows
th
at
the CIF Unit detected the end of
the receive data because the End
Detected in the Port Status in the input
notification data is TRUE.
• The CIF Unit inputs the following input
notificatio
n data and
tells the CPU Unit or
communications master that ABCD was
sent to the serial line.
• At the same time, the CIF Unit tells the
CPU Unit or co
mmunications master that
the end of the receive data was detected.
8 Input
re
sponse
for end
detection
The communications master outputs the
following output notification
data to tell
the CIF Unit that notification of the detec-
tion of the end of the receive data was
receiv
ed normally.
• The CIF Unit receives the output notifica-
tion data given on the left.
• The CIF Unit knows that the CPU Unit or
communica
ti
ons master has normally
received the notification of the detection of
the end of the receive data because the
Input SID Response in the output notifica-
tion data is 04 hex.
*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. In this example, the end is not detected when the CIF Unit receives ABCD.
7-4-4 Example for a Parity Error during Data Reception
NX object name Value
Port Status 8012 hex
Input SID 04 hex
Output SID Response 03 hex
Input Data Type 2000 hex
Input Sub Info 0000 hex
Step Process
CPU Unit or communications master
processing
Communi-
cations
direction
*1
CIF Unit processing
Incremented.
The Send
Completed Toggle
Bit changed.
End was detected.
0 bytes
This is the final
receive data.
8012 hex
04 hex
03 hex
2000 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
03 hex
04 hex
0000 hex
0000 hex
0000 hex
00 hex,
00 hex,
00 hex,
00 hex
Set the Input
SID.
Output SID
Input SID
Response
Output Data
Type
Output Sub Info
Output Data
Length
Output Data 01