XStream™ Advanced Programming & Configuration

XStream Advanced Programming & Configuration – Advanced Manual v4.2A
Flow Control Signal Pinouts
Pin 1 = DO2 (Data Out 2)
The DO2 pin informs the host device whether or not serial data can be sent to the
XStream Module from the host device. When Pin 1 is asserted (low), serial data is permitted to be
sent to the XStream Module. In RS-232 applications, Pin 1 is directly associated with the DI
Buffer. In RS-485/422 applications, the Pin 1 signal controls the transmit driver (TX enable) on
the RS-485 and RS-422 logic converters (on the MaxStream Interface Board or equivalent). Pin 1
utilizes a 10KΩ Pull-Up resistor that is already installed in the module. In some applications, Pin 1
may not need to be observed.
Hardware Flow Control
If the DI Buffer reaches its capacity, either the
line or XON / XOFF flow control must be
observed to prevent loss of data between the host device and the XStream Module. There are two
cases in which the DI Buffer may become full:
1. If the serial interface rate is set higher than the default baud rate for the module, the
module will receive serial data faster than it is transmitted.
2. If the XStream Module is receiving a continuous stream of data or if it is monitoring data
on a network, any serial data that arrives on the DI pin is placed in the DI Buffer. This data
will be transmitted when the module no longer detects RF data in the network.
XON Software Flow Control
XON/XOFF software flow control can be used (on Pin 3) instead of
[See FL (Software Flow Control) Command for more information]
hardware flow control.
Pin 5 = DI2 (Data In 2)
The Pin 5 signal can be configured to enable flow control recognition or binary
command programming. Use RT (DI2 Configuration) Command to adjust the parameters that
control Pin 5 flow control and binary programming options. By default, flow control is not
enabled. This pin utilizes a 10KΩ Pull-Down resistor already installed in the module.
Hardware Flow Control
If flow control is enabled, no data is sent out the DO pin when is de-asserted (high). If
flow control is implemented on the host device, RT Parameter must be set on the XStream
Module in order to recognize the signal as a flow control line.
If is asserted (low), all received RF data is placed in the DO Buffer until the line is deasserted.
Once the DO Buffer reaches capacity, any additional received RF data is lost.
XOFF Software Flow Control
XON/XOFF software flow control can be used (on Pin 4) to simulate
[See FL (Software Flow Control) Command for more information]
hardware flow control.
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