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3. Instructions
DRXDU
Instruction
DIRECT RECEIVE VIA
SERIAL COMMUNICATIONS
UNIT
Symbol
Applicable Program Areas
Function block
Area
definitions
Usage
OK
Operands
Operand
D
First destination word
C
First control word
N
Number of bytes 0000 to 0100 hex (0 to 256)
C: Control word
15
12
11
8
7
4
3
C
0
0
RS and ER signal control
0: No RS and ER signal control
Always 00
1: RS signal control
2: ER signal control
3: RS and ER signal control
Operand Specifications
Word addresses
Area
CIO
WR
HR
D
C
OK
OK
OK
N
868
Mnemonic
Variations
DRXDU
@DRXDU
DRXDU(261)
Block program areas
Step program areas
OK
OK
Description
0
Byte order
0: Most significant bytes first
1: Least significant bytes first
AR
T
C
DM
EM
OK
OK
OK
OK
OK
Function
code
Reads the specified number of bytes of data from
the serial port of a CJ1W-SCU22/SCU32/SCU42
Serial Communications Unit to CPU Unit memory
starting at the specified first word. The data is
read in no-protocol mode with the start code and
261
end code (if any) specified in the allocated DM
Setup Area.
This instruction reads the data from the Serial
Communications Unit as soon as the instruction is
executed to achieve high-speed data reception.
DRXDU
D
D: First destination word
C: First control word
C
N: Number of bytes
N
0000 to 0100 hex (0 to 256)
Subroutines
OK
15
12
11
8
7
4
C+1
0
Serial port number
1: Port 1
2: Port 2
Always 0
Indirect DM/EM
addresses
Con-
stants
@DM
*DM
DR
@EM
*EM
---
---
OK
OK
OK
OK
CS/CJ/NSJ Series Instructions Reference Manual (W474)
Function
SFC action or
Interrupt tasks
transition programs
OK
OK
Data type
Size
UINT
Variable
UDINT
2
UINT
1
3
0
Destination unit address (See note.)
Serial Communications Unit's unit
address (unit number + 10 hex)
Registers
Pulse
TK
CF
bits
Indirect
IR
using IR
---
OK
---
---
TR
bits
---
---
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