Table of Contents
Advertisement
5. HALF-DUPLEX COMMUNICATIONS USING THE RS-232C INTERFACE
M C I
cep-n
(2) AiSJ71C24 is set to
"
non-priov:*-,
"
-
SD (send data)
" L y
.
Continue data transmission
RS (send request)
1
CS (clear to send)
8eauseAlSJ71C24 knth,
'non.~~C,nv',
d a f a v v i i a n is
ivterupptedwmthec~
d g d
External device
t u r m o ~ .
CD (receive carrier
detect)
-
RD (received data)
A1 SJ71 C24
Data C
r
[Il l
Data C
l l l l l l
Data A
-
Data B
The following steps describe the operations performed by AlSJ71C24 at
every thing. The signal names are of the signals of the AlSJ71C24.
Data B
As described in (I), turn ONIOFF the RS signal of the AlSJ71C24 and do
data transmission to the external device.
Note that 5) is different
1) When not transmitting data from the external device to the
AlSJ71C24, turn the RS signal OFF.
2) When doing a data send, check the CD signal. If the CD signal
is OFF, turn the RS signal ON.
If the CD signal is ON, wait until it turns OFF. After the CD is
turned OFF, turn ON the RS signal.
3)
After turning the RS signal ON, transmit data.
4) After completing the data send, turn OFF the RS signal.
5) If the CD signal turns ON during data send, stop the data send.
Then, turn the RS signal OFF and perform data receive process-
0
ing. (This occurs when the AlSJ71C24 and an external device
start data transmission simultaneously.)
6)
After transmission from the external device is completed, resend
all data from the beginning, or transmit data remaining after the
send interruption in 5).
*1
Data set at buffer address 11 O H is not transmitted.
*2
Resend all data from the beginning, or transmit data remaining
after the send interruption according to the setting of buffer
address 11 1 H.
]REMARK/
When (a) starting or during the data transmission to the external device and (b) if the DSR(DR)
signal
of
AlSJ71C24 turns OFF or when a DC3 code is received, interrupt data transmission
until the DSR signal turns ON or until a DC1 code is received.
Advertisement
Table of Contents
