5
Fastcom
®
: G422/X-PCIe
INTRODUCTION
The Fastcom PCIe bus, asynchronous RS-422/485 adapters
utilize the latest technology to live up to today’s
requirements for high bandwidth in communication systems. The Fastcom: 422/4-PCIe and 422/8-PCIe (referred
to hereafter as Fastcom: G422/X-PCIe) are capable of operating at virtually any baud rate up to an astounding
maximum serial data rate of 25 Mbps. There is no fine print or asterisks pointing to notes; this card is capable of
running at the maximum data rate, without any jumpers or hardware changes, right out of the box.
The Fastcom: G422/X-PCIe adapters utilize an advanced quad Universal Asynchronous Receiver and
Transmitter (UART). Each channel of the 17V35x UART is independently controlled and has its own 16C550
compatible register set. Each UART contains its own receive and transmit FIFOs of 256 bytes with
programmable trigger levels.
Each of the UART channels on the board can be independently configured as either RS-422 or RS-485 for full or
half-duplex communication. This is implemented using an automatic RS-485 transmitter enable/disable function
that permits the hardware itself to regulate data flow by only driving lines while actively transmitting. This provides
increased speed and convenience over the older software controlled method, while still allowing the use of the
software method of flow control. Optionally, in automatic RS-485 mode, the receiver can be disabled during
transmits to avoid a receive echo, common in 2-wire 485 networks.
Additionally, each board utilizes a programmable clock generator to create the UART
’s input frequency. The
clock generator is capable of generating frequencies between 6 and 50 MHz. Utilizing this feature, it is possible
to configure the board to operate at virtually any serial data rate that the user desires (up to 25 Mbits/second
maximum).
With the supplied software driver, the ports on the Fastcom: G422/X-PCIe cards will be seen as standard COM
ports and can utilize all the same functions as a standard serial device. With the addition of a few simple I/O
commands to control the unique features of the board, the standard software interface to a serial port can be used
to simplify program design. C, C++, .NET and python libraries are provided to demonstrate how to effectively use
the serial interface as well as control the board-specific features.
Overall, the Fastcom: G422/X-PCIe RS-422/485 adapters are ideal for commercial and industrial applications
demanding high data rates, reliability and ease of use.
Software drivers for Windows XP through Windows 8 and Linux are supplied. Multiple Fastcom: G422/X-PCIe
adapters can be installed in all operating systems.
