SENA DirectPort-USB User Manual

Page 27

DirectPort-USB

Page 27 of 36

This page allows configuration of the basic device parameters (i.e. Baud rate, data bits, parity, stop bits

and flow control).

To access more advanced settings, click on the "Advanced… " button to display the

advanced properties page (shown below).

This page will allow the following parameters to be altered:

 COM port number
 USB buffer sizes
 Latency timer
 Alter this to correct compatibility problems for obsolete applications.
 Read and write timeout values
 You can alter this for timing of timeout event if there are no more Tx/Rx data.
 Miscellaneous options
 Serial Emulator : The function of the serial enumerator is to detect a Plug-and-Play enabled

device (such as a serial mouse or serial modem) that is attached to the USB serial port.

 Serial Printer : If enabled, serial printer will disable timeouts to allow for long delays associated

with paper loading.

 Cancel If Power Off : The Cancel If Power Off option can be used to assist with problems

encountered when going into a hibernate or suspend condition.

This will cancel any requests

received by the driver when going into hibernate or suspend.

 Event on Surprise Removal : The Event On Surprise Removal option is generally left

unselected.

If an application sets SERIAL_EV_EVENT2 (refer Windows DDK) in it's event

bitmask and this feature is enabled, the device driver will signal this event on surprise removal.

 Set RTS on Close : Selecting the Set RTS On Close option will set the RTS signal on closing

the port.

 Disable Modem Control at Startup : This option is used to control the modem control signals

DTR and RTS at startup.

In normal operation, the modem control signals at startup follow the

behavior of the legacy port.

However, due to timing differences between a legacy COM port

and a virtual COM port, a "spike" on one of these signals in the legacy port can appear as an

assertion of the signal in the virtual COM port.

 Devices that monitor these signals can enter the wrong state after an unplug-replug cycle on

USB. Note that if the "Serial Enumerator" option in the property page is selected, then the