2: Description
and Specifications
xPort® Pro Embedded Device Server Integration Guide
9
PCB Interface
The xPort Pro has a serial port compatible with data rates up to 921600 bps. The
serial signals (pins 4–8) are 3.3V CMOS logic level. The serial interface pins include
+3.3V, ground, and reset. The serial signals connect to an internal UART driven at
3.3V. For applications requiring an external cable running with RS-232 or RS422/485
voltage levels, the xPort Pro must interface to a serial transceiver chip. We supply an
RS-232 transceiver on the xPort Universal Demo Board for this purpose.
Note:
The standard baud rate of 460800 bps is not supported.
Table 2-2 PCB Interface Signals
Signal Name
xPort Pro
Pin #
Primary Function
GND
1
Circuit ground
3.3V
2
+3.3V power in
Reset
3
External reset in
Data Out
1
4
Serial data out (driven by built-in UART)
Data In
5
Serial data in (input to built-in UART)
CP1/RTS
(Configurable Pin 1)
6
CP1 can be configured as follows:
•
Flow control
: RTS (Request to Send)
output
driven
by the built-in UART for connection to CTS of
attached device.
•
Programmable input/output
: CP1 can be driven or
read through software control, independent of serial
port activity.
•
RS485 Transmit Enable:
In RS485 mode, CP1 is
driven by the built-in UART for connection to the
transmit enable pin of an RS485 Transceiver.
CP2/DTR
(Configurable Pin 2)
7
CP2 can be configured as follows:
•
Modem control
: DTR (Data Terminal Ready)
output
driven by the built-in UART for connection to
DCD of attached device.
•
Programmable input/output
: CP2 can be driven or
read through software control, independent of serial
port activity.
CP3/CTS/DCD
(Configurable Pin 3)
8
CP3 can be configured as follows:
•
Flow control
: CTS (Clear to Send) input read by
the built-in UART for connection to RTS of attached
device.
•
Modem control
: DCD (Data Carrier Detect)
input
read by the built-in UART for connection to DTR of
attached device.
•
Programmable input/output
: CP3 can be driven or
read through software control, independent of serial
port activity.
1
Data out will float during and immediately after power up or assertion of RESET on Pin 3. Pin 4 can be pulled
up to +3.3V with a 10K ohm or larger resistor to hold the pin high during reset.
