Kontron PCI-COM-8ULP, Руководство пользователя

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page 16 PCI-COM-8ULP User’s Guide
COM Port Compatibility
Eight Type 16550 compatible UARTs incorporated within a single octal UART are used
as Asynchronous Communication Elements (ACE). These include 64-byte transmit &
receive buffers to protect against lost data in multitasking operating systems, while
maintaining 100 percent compatibility with the original IBM serial port. The system
assigns the address(es).
A crystal oscillator is located on the card. This oscillator permits precise selection of
baud rate up to 115,200 or, by changing a jumper, up to 921,600 with the standard
crystal oscillator.
The driver/receiver used, the SP841 in non-RS232 modes, is capable of driving
extremely long communication lines at high baud rates. It can drive up to +60 mA on
balanced lines and receive inputs as low as 200 mV differential signal superimposed on
common mode noise of +12 V or -7 V. In case of communication conflict, the
driver/receivers feature thermal shutdown.
The driver/receiver used in RS232 mode is the SP211.
Communication Mode
The card supports Half-Duplex communications with a 2-wire cable connection. Half-
Duplex allows traffic to travel in both directions, but only one way at a time. RS485
communications commonly use the Half-Duplex mode since they share only a single
pair of wires.
Baud Rate Ranges
The card has capability for two baud rate ranges and you can select which you wish to
use for all ports on the card. One range is up to 115,200 baud and the other is up to
921,600 baud.
Note:
Refer to the Baud Rate Divisor Values table in chapter 3 of this manual.
Auto-RTS Transceiver Control
In RS485 communications, the driver must be enabled and disabled as needed,
allowing all cards to share a two wire cable. The card controls the driver automatically.
With automatic control, the driver is enabled when data is ready to be transmitted.
With this card, the driver remains enabled for an adjustable period. It may be disabled at
the completion of the transmission of the character (default), or can be set to wait up to
one additional character's transmission time after data transfer is complete and then
disabled.