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6-4SectionUsing No-protocol Communications
104
6-4-2 TXD(––) Communications Procedure
Confirm that the Transmission Enabled Flag is ON before executing TXD(––).
The Port 1 Transmission Enabled Flag is IR 20105 and the Port 2 Transmission
Enabled Flag is IR 20113. The Transmission Enabled Flag will turn OFF while
TXD(––) is being executed and will turn ON when the send has been completed.
First source word
Control word
Number of bytes
(4 digits BCD, 0000 to 0256)
TXD(––)
S
C
N
Byte order 0: Most significant bytes first
1: Least significant bytes first
Not used. (Set to 0.)
Port 0: RS-232C port on CPU Unit
1: Port 1 on Serial Communications Board
2: Port 2 on Serial Communications Board
Not used. (Set to 0.)
15 00
00
C: Control Word
Note Do not let TXD(––) be executed unless the Transmission Enabled Flag is ON.
6-4-3 RXD(––) Communications Procedure
The Reception Completed Flag will turn ON when data reception has been com-
pleted. The Port 1 Reception Completed Flag is IR 20106 and the Port 2 Recep-
tion Completed Flag is IR 20114.
When RXD(––) is executed, the receive data is stored in the specified data with-
out any start or end code and the Reception Completed Flag is turned OFF.
Reception is started when the start code is received. If the start code is disabled,
then data is received continually.
Reception is completed when the end code is received. If the end code is dis-
abled, then reception is completed when the specified number of bytes or
259 bytes have been received.
First destination word
Control word
Number of bytes
(4 digits BCD, 0000 to 0256)
RXD(––)
D
C
N
Byte order 0: Most significant bytes first
1: Least significant bytes first
Not used. (Set to 0.)
Port 0: RS-232C port on CPU Unit
1: Port 1 on Serial Communications Board
2: Port 2 on Serial Communications Board
Not used. (Set to 0.)
15 00
00
C: Control Word
The following flags and status information are available in the IR area. All bits are
cleared when RXD(––) is executed.