If "None" Is Set For Start And Terminal Codes - Panasonic FP0 User Manual

General−use Serial Communications
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
A
External received
data
on
R9038
Reception
off
completed flag
on
F144 (TRNS)
instruction
off
execution
on
R9039
Transmission
completed flag
off
Transmitted data
Reception A
buffer
<1>
Number of recep-
tion bytes
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.
10 − 8
C
B CR
Stored
A A
B
B
C
<2> <3>
Number of bytes received is
Write pointer
cleared when F144 (TRNS)
instruction is executed
D
Cannot be stored when
reception completed
flag is on
Duplex transmission dis-
abled while F144 (TRNS) in-
struction is being executed
1 2 3
A
B
C
<0>
FP0
E F
G
CR
E E E
B
F
B
C C G
<1> <2> <3>