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1018
Serial Communications Instructions
Section 3-24
RXDU(255) can not be executed while the Reception Completed Flag (bit 6
of n+9 or n+19, where n = CIO 1500 + 25
×
unit number) is ON. Program the
Reception Completed Flag as a normally open condition of RXDU(255).
An error will occur and the Error Flag will turn ON in the following cases.
• The Communications Port Enabled Flag for the specified logical port is
OFF when RXDU(255) is executed.
• The value of C is not within range.
• The value for N is not between 0000 and 0100 hex.
Note
1.
Reception Completed Flags (n = CIO 1500 + 25
×
unit number)
Port 1:
Bit 6 of n+9
Port 2:
Bit 6 of n+19
2.
Reception Counters (n = CIO 1500 + 25
×
unit number)
Port 1:
n+10
Port 2:
n+20
3.
Reception Overflow Flags (n = CIO 1500 + 25
×
unit number)
Port 1:
Bit 7 of n+9
Port 2:
Bit 7 of n+19
4.
Overrun Error Flags (n = CIO 1500 + 25
×
unit number)
Port 1:
Bit 4 of n+8
Port 2:
Bit 4 of n+18
5.
Transmission Error Flags (n = CIO 1500 + 25
×
unit number)
Port 1:
Bit 15 of n+8
Port 2:
Bit 15 of n+18
6.
Further data cannot be received until the received data is read from the
buffer with RXDU(255). When the Reception Completed Flag goes ON,
read that data promptly with RXDU(255) before more data is input to the
port.
7.
When RXDU(255) is used to read data that was received at one of the Se-
rial Communications Unit’s ports, the port’s reception buffer is cleared after
RXDU(255) is executed. Consequently, RXDU(255) can
not
be executed
repeatedly to read a block of data in parts.
CPU Unit
RXDU
RXDU
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...