NAiS FP Series, User Manual

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FP
Σ
9.6 Flag Operations When Using Serial Communication
9 - 33
9.6 Flag Operations When Using Serial Communication
This section explains about the operation of “reception done flag” and “transmission
done flag” when using serial communication.
9.6.1 When “STX not exist” is Set for Start Code and “CR” is Set for End
Code
When receiving data:
Relationship between the various flags “Reception done flag and Transmission done
flag” and the F159 (MTRN) instruction
External received
data
Reception
done flag
“R9038 or R9048”
F159 (MTRN)
instruction
execution
A B
C CR
D
E
F G
Transmission
done flag
“R9039 or R9049”
Transmitted data
1
2
3 CR
Duplex transmission
disabled while F159 (MTRN)
instruction is being executed
Cannot be stored when
reception done flag is on.
A
A
B
B
C
A
B
C
A
B
C
E
F
C
E
B
G
E
<1>
<2> <3>
<0>
<1>
<2> <3>
Reception
buffer
Number of recep-
tion bytes
Stored
Number of bytes received is
cleared when F159 (MTRN)
instruction is executed
on
off
on
off
on
off
* : Write pointer
Write pointer
* : Write pointer
Figure 197: FP
Σ
Flag operation when receiving data (STX not exit and CR setting)
Half-duplex transmission method should be used for general-purpose serial
communication.
Reception is disabled when the reception done flag “R9038 or R9048” is on.
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