972
Serial Communications Instructions
Section 3-24
Example
In this example, IOWR(223) is used to write data.
3-24 Serial Communications Instructions
This section describes instructions used for serial communications.
3-24-1 Serial Communications
There are two types of serial communications instruction. The TXD(236),
RXD(235), TXDU(256), and RXDU(255) instructions send and receive data in
no-protocol (custom) communications with an external device. PMCR(260)
sends and receives data using user-defined protocols with an external device.
The difference is shown in the following tables.
Note
1.
The TXD(236) and RXD(235) instructions transfer data only through the
CPU Unit’s built-in serial port or a serial port on a Serial Communications
Board (Ver. 1.2 or later).
2.
The TXDU(256) and RXDU(255) instructions transfer data only through a
Serial Communications Unit (Ver. 1.2 or later).
D
D+1
D
CPU Unit
When CIO 000000 is turned ON, the 10 words in D00100 to
D00109 are written to the Special I/O Unit.
Number of words
to transfer: 10
Unit number: 3
The control code (C) varies depending on the Special I/O Unit.
Special I/O Unit (Unit #3)
10 words
Instruction
Mnemonic
Function code
Page
PROTOCOL MACRO
PMCR
260
974
TRANSMIT TXD
236
983
RECEIVE RXD
235
993
TRANSMIT VIA SERIAL COMMU-
NICATIONS UNIT
TXDU
256
1005
RECEIVE VIA SERIAL COMMU-
NICATIONS UNIT
RXDU
255
1013
CHANGE SERIAL PORT SETUP
STUP
237
1021
Summary of Contents for SYSMAC CS Series
Page 2: ......
Page 4: ...iv ...
Page 30: ...xxx ...
Page 186: ...146 List of Instructions by Function Code Section 2 4 ...
Page 1320: ...1280 Model Conversion Instructions Unit Ver 3 0 or Later Section 3 35 ...
Page 1390: ...1350 CJ series Instruction Execution Times and Number of Steps Section 4 2 ...
Page 1391: ...1351 Appendix A ASCII Code Table ASCII SP Four leftmost bits Four rightmost bits ...
Page 1392: ...1352 ASCII Code Table Appendix A ...
Page 1404: ...1364 Revision History ...