1012
Serial Communications Instructions
Section 3-24
Related Flags in the CPU Bus Unit Area
(n = CIO 1500 + 25
×
unit number)
Example: Flag Operation
The following diagram shows the operation of the Communications Port
Enabled Flag and TXDU Instruction Executing Flag.
Example: Sending Data
When CIO 000000 is ON, A20203 (the Communications Port Enabled Flag) is
ON, and CIO 155905 (the TXDU Instruction Executing Flag for port 1) is OFF
in the following example, TXDU(256) outputs data through serial port 1 of the
Serial Communications Unit with unit number 2. The 5 bytes of output data
are read from the DM Area beginning at the rightmost byte of D00100 and
output through logical port 3 to a general-purpose device such as a printer.
Word
Bit
Name
Status
Port 1
Port 2
n+9
n+19
05
TXDU Instruction
Executing Flag
0: TXDU(256) is not being executed.
1: TXDU(256) is being executed.
Instruction
execution
ON
OFF
Communications Port Enabled Flag
(A20200 to A20207 correspond to
communications ports 0 to 7.)
TXDU(256)
CPU Unit
TXDU Executing Flag
(Bit 5 of n+9 or n+19,
n = CIO 1500 + 25 x unit number)
ON
OFF
Send processing
Send
processing
Serial
Communications
Unit
Send starts.
Send completed.
Summary of Contents for SYSMAC CS1D-CPU**
Page 3: ...iv...
Page 29: ...xxx...
Page 185: ...146 List of Instructions by Function Code Section 2 4...
Page 1389: ...1350 CJ series Instruction Execution Times and Number of Steps Section 4 2...
Page 1390: ...1351 Appendix A ASCII Code Table ASCII SP Four leftmost bits Four rightmost bits...
Page 1391: ...1352 ASCII Code Table Appendix A...