Page 12 of 26
pulled high with a 10K ohm resistor to enable tri-state oscillators. The max frequency is 50MHz
which
will
result in a max
baud rate of
6.25Mbps.
Serial Port Connectors, CN4-CN11
The following sections describe the external I/O connections of the CM17320HR board. For
information on the I/O connections for the IDAN version, refer to the IDAN-CM17320HRS section
later in this manual.
First serial port, CN4
The first serial port is implemented on connector CN4. It can be configured as a PC compatible
full duplex RS-232 port, full duplex RS-422 with drivers always enabled, RS-485 with RTS driver
enable, or RS-485 with inverted RTS driver enable by the “Mode A and B” jumpers. See Table 5
– Jumper Settings for details.
RS-232 Serial Port Mode (Default)
The full-duplex RS-232 mode is the default setting on the utilityModule. With this mode enabled,
connector CN4 must be connected to RS-232 compatible devices. The following table gives the
connector pinout and shows how to connect to an external serial connector, either DB25 or DB9.
Table 1 Connector CN4 in RS-232 Mode (I)
CN4 Pin
Signal
Function
In/out
DB25
DB9
1
DCD
Data Carrier Detect
In
8
1
2
DSR
Data Set Ready
In
6
6
3
RXD
Receive Data
In
3
2
4
RTS
Request To Send
Out
4
7
5
TXD
Transmit Data
Out
2
3
6
CTS
Clear To Send
In
5
8
7
DTR
Data Terminal Ready
Out
20
4
Pin 1 OE
Pin 4 VCC
(Set by JP27)
Pin 2 GND
Pin 3 CLOCK
User Oscillator U3 Pinout
