Adding Serial Ports - Technologic Systems TS-3200 User Manual

TS-3200 User's Manual
transmitter and receiver share a single pair of signals that are available on pins 1 and 6 of the COM1
10-pin header, as well as on the 3-pin terminal block connector.
When COM1 is configured for RS-485 usage, the COM1 RS-232 port must not be connected. Data
received on the RS-232 port will corrupt RS-485 data.
It is possible to use COM1 in RS-232 mode even when the
RS-485 option has been ordered. To disable RS-485 (and
enable RS-232) on COM1, simply remove the 8-pin RS-485
transceiver from the 8-pin socket (near the center of the
board).

5.4 Adding Serial Ports

If your project requires more than two serial ports, additional
ports may be added via the PC/104 expansion bus.
Technologic Systems currently offers a 2 serial / 1 parallel
port card, the TS-SER2, and other manufacturers sell cards
with up to four additional serial ports. Typically these would
be configured as COM3 or COM4 or be assigned other non-
standard I/O locations. Because DOS only directly supports
four serial ports, any additional ports beyond four will require
software drivers.
The PC/104 bus has IRQ3, 4, 5, 6, 7 or 9 available for additional serial ports. If IRQ3 or 4 are to be
used on a PC/104 expansion card, then care must be taken since COM2 and COM1 also use these
IRQs, respectively. For example, if IRQ4 is used for COM3 then either COM1 must be used in a non-
interrupt fashion or only one COM port can have the interrupt enabled at a time. In any case only one
COM should have the Interrupt Enable (Bit 3 of Modem Control Reg.) set at any one time if they share
the same IRQ. This is a standard problem with the PC architecture. A better solution is to simply use
interrupts other than 3 or 4 for additional serial ports.
RS-485 Quick start procedure:
1. The RS-485 option must be installed
2. Attach the RS-485 cable to pins 1 and
6 of the COM1 header or the 3-pin
RS-485 header.
3. Set the COM1 UART serial
parameters (baud rate, data, parity,
and stop bits, interrupts, etc).
4. To transmit data, assert RTS and
write the data to the UART
5. To receive data, deassert RTS and
read the data from the UART
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Technologic Systems
05/21/2009