7 Serial Communications
7 - 10
NX-series Communications Interface Units User’s Manual (W540)
The Output SID and Output SID Response are used when the CPU Unit or communications master
outputs send data to the CIF Unit. They are used in the same way as the Input SID and Input SID
Response.
If the send data size is larger than the divided data size, the send
data is separated into more than one
piece of data and sent from the CPU Unit or communications master to the CIF Unit. If the receive data
size is larger than the divided data size, the receive data is separated into more than one piece of data
and sent from the CIF Unit to the CPU Unit or communications master.
It is therefore necessary for the CPU Unit or commun
ica
tions master to tell the CIF Unit whether the
sent output data is final or if other data will follow. The same thing is true when the CIF Unit sends input
data to the CPU Unit or communications master. The following data is used for that purpose: Input Data
Type in the input notification data and Output Data Type in the output notification data.
The following table gives the meanings of bits
1
2 to 14 of the Input Data Type and bits 12 to 15 of the
Output Data Type.
The send data that the CPU Unit or communications mast
er sends to the CIF Unit is then sent to the
serial line.
The Send Completed Toggle Bit changes between TRUE and FALSE each time the send data is sent to
the ser
ial line until the final data is sent. The default value of the Send Completed Toggle Bit is FALSE.
The following table gives an operation example
for the Send Completed Toggle Bit.
Output SID and Output SID Response
7-3-3 Input Data Type and Output Data Type
Data Description
Bits 12 to 14 in the Input Data Type Presence of receive data received by the CIF Unit from the serial line
0 hex: No data received, and the end not detected.
1 hex: Data received, and the end not detected.
2 hex: The end detected.
Whether there is data received depends on
cases.
*1*2
*1. The value will be 2 hex only when the Number of Characters to Determine the End is set to a value other than
0. If the Number of Characters to Determine the End is set to 0 and there is receive data, the value will be 1 hex.
*2. If the Number of Characters to Determine the End is not set to 0, the value will be 1 hex when the last data is
received. The value will then change to 2 hex when the end is detected.
Bits 12 to 15 in the Output Data Type Presence of send data sent by the CIF Unit to the serial line
0 hex: No data sent.
1 hex: Data sent but not the last.
2 hex: Last data sent.
7-3-4 Send Completed Toggle Bit
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