Communication Flow Control; Flow Control During Transmit; Flow Control During Receive - Yamaha RCX240 User Manual

3. Communication specifications
3.3

Communication flow control

1
Software flow control (XON/XOFF) and hardware flow control (RTS/CTS) methods can be selected
by specifying the communication parameters.
3.3.1

Flow control during transmit

2
XON/XOFF and CTS indicate whether the other party can receive data.
Flow Control
XON/XOFF
3
RTS/CTS
n
NOTE
4
1) Transmission stops when transmission is disabled in either of XON/XOFF or RTS/CTS
2) CTS must be on during transmission regardless of flow setting. When RTS/CTS is set
5
3.3.2

Flow control during receive

6
To prevent overflow when receiving data, XOFF and RST are used to notify the other party that this
end is busy.
Flow Control
7
XON/XOFF
8
RTS/CTS
n
NOTE
9
The flow controls the functions separately. For instance, when all flow controls are
set to "Yes" and the receive buffer capacity is low, an XOFF is transmitted, and RTS is
turned off. Later, when the receive buffer capacity is restored, an XON is
transmitted, and RTS is turned on.
10
8-6
Chapter 8 RS-232C INTERFACE
Temporarily stops transmission
when XOFF is sent from the other
party.
Resumes transmission when XON
is sent.
Stops transmission while CTS is
OFF.
flow control.
to "No", the CTS should always be set on. However, if CTS is connected to RTS of
the other party, CTS may not always be on causing the transmission to halt,
depending on the other party specifications.
Transmits XOFF when available
space in receive buffer falls below
a certain capacity.
Transmits XON when receive buffer
is empty.
Turns RTS off when available
space in receive buffer falls below
a certain capacity.
Turns RTS on when receive buffer
is empty.
Yes
XON (11H) and XOFF (13H) do not
affect transmission even when they
are received.
Stops transmission while CTS is
OFF.
Yes
XON and XOFF are not transmitted.
XON and XOFF are ignored if
received.
RTS is always on.
No
No