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Data Exchange with the CPU Unit Section 2-2
2-2 Data Exchange with the CPU Unit
Data exchange with the CPU Units uses the I/O memory allocated to the
Serial Communications Board and Serial Communications Unit. For details on
allocations, refer to 2-3 I/O Memory Allocations.
2-2-1 Serial Communications Board (CS Series Only)
Note 1. Set the Serial Communications Board mode and the communications set-
tings (System Setup) in the words allocated in the DM Area. Use a Pro-
gramming Device, such as a Programming Console or the CX-
Programmer, to make these settings. The System Setup is transferred to
the Serial Communications Board at the following times:
• When the power to the CPU Unit is turned ON, when the Serial Com-
munications Board is restarted (A60800 is turned ON), or when the
STUP(237) instruction is executed.
• When the Port 1 Port Settings Change Bit (A63601) or Port 2 Port Set-
tings Change Bit (A63602) is turned ON.
2. When STUP(237) is executed, the CPU Unit automatically turns ON the
Port 1 or Port 2 Port Settings Change Bit and updates the System Setup.
For details on the STUP(237) instruction, see Appendix O Changing Com-
munications Port Settings Using STUP(237).
CPU Unit Serial Communications Board
Inner Board Area in
CIO Area
Software switch
Local memory
Status
Inner Board Area in
DM Area
System Setup (see note 1)
Auxiliary Area
Port Settings
Change Bits
(see note 2)
Restart Bits
Error Information
Local memory
(System Setup)
Error information
25 words
20 words
CIO 1900
CIO 1999
D32000
D32099
A636
A608
A424