Omron SYSMAC CJ - REFERENCE MANUAL 08-2008

1014
Serial Communications Instructions Section 3-24
Operand Specifications
Description RXDU(255) reads data that has been received in no-protocol mode at the
Serial Communications Unit with the unit address specified in bits 0 to 7 of
C+1, through the port specified with bits 8 to 11 of C+1, and stores that data
starting at D. If fewer than N bytes of data have been received at the port, then
only the data that has been received will be stored. The logical port number
can be set to any value between 0 and 7 and is specified with bits 12 to 15 of
C+1.
Execute RXDU(255) to read the received data from the buffer when the
Reception Completed Flag (in the allocated DM Setup Area) is ON.
Up to 259 bytes can be received, including the receive data (N = 256 bytes
max.), the start code, and the end code.
The following diagram shows the order in which data is received and the con-
tents of the receive frame for various settings.
Note The logical port number can be allocated automatically by setting bits 12 to 15
of C+1 to F. For details, refer to Automatic Allocation of Communications Ports
on page 1032.
Area DCD
CIO Area CIO 0000 to CIO
6143
CIO 0000 to CIO
6142
CIO 0000 to CIO
6143
Work Area W000 to W511 W000 to W510 W000 to W511
Holding Bit Area H000 to H511 H000 to H510 H000 to H511
Auxiliary Bit Area A000 to A959 A000 to A958 A000 to A959
Timer Area T0000 to T4095 T0000 to T4094 T0000 to T4095
Counter Area C0000 to C4095 C0000 to C4094 C0000 to C4095
DM Area D00000 to
D32767
D00000 to
D32766
D00000 to
D32767
EM Area without bank E00000 to
E32767
E00000 to
E32766
E00000 to
E32767
EM Area with bank En_00000 to
En_32767
(n = 0 to C)
En_00000 to
En_32766
(n = 0 to C)
En_00000 to
En_32767
(n = 0 to C)
Indirect DM/EM
addresses in binary
@ D00000 to @ D32767
@ E00000 to @ E32767
@ En_00000 to @ En_32767
(n = 0 to C)
Indirect DM/EM
addresses in BCD
*D00000 to *D32767
*E00000 to *E32767
*En_00000 to *En_32767
(n = 0 to C)
Constants --- Specified values
only
#0000 to #0100
(binary) or &0 to
&256 (decimal)
Data Registers --- --- DR0 to DR15
Index Registers ---
Indirect addressing
using Index Registers
,IR0 to ,IR15
–2048 to +2047 ,IR0 to –2048 to +2047 ,IR15
DR0 to DR15, IR0 to IR15
,IR0+(++) to ,IR15+(++)
,–(– –)IR0 to, –(– –)IR15