Yamaha CEmarking RCX221, User Manual

Page: 390 / 468

7-6
Chapter
7
RS-232C INTERF
ACE
3.3 Communication flow control
Software flow control (XON/XOFF) and hardware flow control (RTS/CTS) methods can be
selected by specifying the communication parameters.
n
NOTE
When fl ow control is set to "XON/XOFF" or "none", CTS status does not affect
transmission. RTS is always on.
When fl ow control is set to "RTS/CTS" or "none", receiving XON and XOFF does
not affect transmission.
When fl ow control is set to "none", part of receive data might be lost.
3.3.1 Flow control during transmit
Data transmission temporarily stops when the other party's device is in receive busy
status.
Communication parameter Operation during transmit
XON/XOFF
Stops transmission when XOFF (13H) is received.
Resumes transmission when XON (11H) is received.
RTS/CTS Stops transmission while CTS is off.
None Does not perform flow control during transmit.
3.3.2 Flow control during receive
This notifies the other party's device that the controller is in receive busy status.
Communication parameter Operation during transmit
XON/XOFF
Transmits XOFF (13H) when available space in
receive buffer falls below a certain capacity.
Transmits XON (11H) when receive buffer is empty.
RTS/CTS
Turns RTS off when available space in receive buffer
falls below a certain capacity.
Turns RTS on when receive buffer is empty.
None Does not perform flow control during receive.
3. Communication specifications