Kontron CP346 - Manual (Page 31)

CP346 Functional Description
ID 27253, Rev. 03 © 2005 Kontron Modular Computers GmbH Page 2 - 3
P R E L I M I N A R Y
2. Functional Description
2.1 General Information
The CP346 serial communications controller board is the realization of a low cost solution for
industrial automation communication purposes and represents the implementation of a serial
communication controller board at the basic OSI levels.
The main functions implemented on the CP346 board are the OSI Layer 2 control for RS232,
RS422 and RS485 communication purposes as well as the OSI Layer 1 physical signal level
adaptation for the above mentioned interfaces, where the RS422/RS485 interface is realized
for half duplex as well as for full duplex operation.
The physical layer adaptation (OSI Layer 1) of the TTL interface signals is realized indepen-
dently for each channel via corresponding on-board RS232, RS422/RS485 transceivers where
each of the four serial communication links are configured individually for serial interface oper-
ation per hardware and software, including the serial line termination for balanced serial com-
munication.
The supply voltage for the CP346 is 5V DC. The isolated board variant is provided with one
5V/5V on-board DC/DC converter.
2.2 Specifics
The OSI Layer 2 functions for serial communication are handled entirely by the Oxford Semi-
conductor serial communication controller OX16PCI954. This controller handles all the on-
board serial communication tasks related to the OSI Layer 2, and also the data transfer to the
system host CPU over the CompactPCI bus.
Configuration of the serial communication links for the various operation types as well as serial
line termination for differential communication (RS422/RS485) is accomplished via hardware
and software. The four serial I/O channels are independent and can be configured individually
for RS232, RS422/RS485 serial communication.
Data transfer operation of the serial channels is indicated at the front panel by four, channel-
related pairs of LEDs for the indication of receive and transmit operations.
All the above mentioned communication functions including the RS232, RS422 and RS485 se-
rial I/O functions are tied to the host system via the standard PCI interface provided directly on
the Oxford semiconductor serial communication controller OX16PCI954. Logical control of the
CP346 serial communication operation is accomplished via the OX16PCI954 command and
status registers which can be accessed independently for each channel directly from the PCI
side.
The CP346 serial I/O board is provided with a 37-pin D-Sub connector providing the signals for
all four serial I/O channels. In order to provide separate serial I/O channelling, a front panel
adapter can be connected to the 37-pin frontend connector. This adapter terminates on the
user side with four, male, 9-pin, D-Sub connectors (one per serial I/O channel).
Optionally, the CP346 provides rear I/O connectivity instead of frontend connectivity, where all
serial signals are routed at TTL level to a J2 rear I/O connector.
In addition to the rear I/O variant, the CP346 is available with galvanic isolation for all four chan-
nels. This is accomplished through the use of digital isolators from Analog Devices which use
iCoupler® technology.