Panasonic FP0 Series, User Manual

Page: 206 / 382

General − use Serial Communications FP0
10 − 8
10.3 Operations When Using General − use Serial Communication
10.3 Operations When Using General − use Serial
Communication
10.3.1 If “None” is Set for Start and Terminal Codes
Relationship between the flags (reception completed flag and
transmission completed flag) and the F144 (TRNS) instruction
External received
data
R9038
Reception
completed flag
F144 (TRNS)
instruction
execution
A
B
C
CR
D E F
G
R9039
Transmission
completed flag
Transmitted data 1 2 3 CR
Duplex transmission dis-
abled while F144 (TRNS) in-
struction is being executed
Cannot be stored when
reception completed
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 F144 (TRNS)
instruction is executed
on
off
on
off
on
off
Write pointer
Half − duplex transmission should be used for general − use serial communication.
Reception is disabled when the reception completed flag (R9038) is on.
Be aware that the reception completed flag (R9038) changes even while a scan is in
progress. (Example: If the reception completed flag is used multiple times as an input
condition, there is a possibility of different statuses existing within the same scan.)
When the
F144 (TRNS) instruction is executed, the error flag (R9037), reception
completed flag (R9038) and transmission completed flag (R9039) go off.
Duplex transmission is disabled while the
F144 (TRNS) instruction is being executed.
Check the transmission completed flag (R9039) to determine whether duplex
transmission is possible.