3
Rev NR
The SIO4BX2 provides access to complete FIFO status to optimize data transfers. In addition to Empty and Full
indicators, each FIFO has a programmable Almost Empty Flag and a programmable Almost Full Flag. These FIFO
flags may be used as interrupt sources to monitor FIFO fill levels. In addition, real-time FIFO counters showing the
exact number of words in the FIFO are also provided for each FIFO. By utilizing these FIFO counters, data transfers
can be optimized to efficiently send and receive data.
1.3
Multiprotocol Transceivers
The SIO4BX2 data is transferred over the user interface using high-speed multiprotocol transceivers. These
multiprotocol transceivers are software selectable as RS422/RS485, or RS232 on a per channel basis. Each channel
direction may also be configured as DTE or DCE configuration. This allows for either full duplex or half duplex
configurations.
1.4
PMC/PCI Interface
The control interface to the SIO4BX2 is through the PMC/PCI interface. An industry standard PCI9056 bridge chip
from PLX Technology is used to implement PCI Specification 2.2. The PCI9056 provides the 32bit, 66MHz
(264MBit/sec) interface between the PCI bus and the Local 32 bit bus. It also provides for high-speed DMA
transfers to efficiently move data to and from the board.
1.5
General Purpose IO
Since some signals may not be used in all applications, the SIO4BX2 provides the flexibility to remap unused signals
to be used as general purpose IO. For example, this would allow support for an application requiring DTR/DSR
signals to be implemented on an unused DCD or TxAuxC signals. This also allows signals from unused channels to
be available as general purpose IO.
1.6
Connector Interface
The SIO4BX2 provides a user IO interface through a front-side card edge connector. All four serial channels
interface through this high-density, 68 pin SCSI-3 type connector, and are grouped to simplify separating the cable
into four distinct serial connectors.
Standard cables are available from General Standards in various lengths to adapt the single 68 pin SCSI-3 connector
into four DB25 connectors (one per channel). A standard cable is also available with a single 68 pin SCSI-3
connector on one end and open on the other. This allows the user to add a custom connector (or connect to a
terminal block). General Standards will also work with customers to fabricate custom cables. Consult factory for
details on custom cables.
1.7
New Features
The PCIe-SIO4BX2 has been enhanced with several new features. These include improved receive data status
recording, timestamping of data, flexible FIFO memory allocation, sync/standard channel select, and channel reset.
