PC104P-SIO4BX User Manual, Revision: 0
General Standards Corporation
8302A Whitesburg Drive Huntsville, AL 35802, Phone: (256) 880-8787
1.1
PMC/PCI Interface
The control interface to the SIO4BX is through the PMC/PCI interface. An industry standard PCI9080 bridge chip
from PLX Technology is used to implement PCI Specification 2.1. The PCI9080 provides the 32bit, 33MHz
(132Mbps) interface between the PCI bus and the Local 32 bit bus.
1.2
Local Control Logic
The control functions and glue logic for the board are implemented in an on-board FPGA. This custom logic defines
local space registers to provide software control over the board functions. The on-board logic adds many custom
features to compliment the Serial Controller chips. These functions include programmable oscillator setup, GPIO
functionality, transfer of data between the serial controller chips and the large external FIFOs, and functions to
simplify data transfer to/from the FIFOs.
1.3
Transmit/Receive FIFOs
Eight independent Transmit and Receive FIFOs provide up to 32kbytes of data buffering per channel for the serial
data. Each channel has a unique transmit and receive FIFO to allow the channels to operate independently. The
large FIFOs allow data transfer to continue independent of PCI interface transfers and software overhead. The
required FIFO size may depend on several factors including data transfer size, required throughput rate, and the
software overhead (which will also vary based on OS). Deep FIFOs ensure no data is lost for critical systems.
1.4
Universal Serial Controllers
Two Zilog Z16C30 Universal Serial Controllers provide the four serial data channels. The Z16C30 USCs serve as
serial/parallel converters which can be software configured to provide a variety of serial protocols. The USCs are
highly configurable to allow for a wide range of serial solutions.
1.5
Multiprotocol Transceivers
Data is transferred over the user interface using high-speed multiprotocol transceivers. These multiprotocol
transceivers can be configured as RS422/RS485, RS423, RS232, RS530, V.35, or RS422/RS423 mixed mode on a
per channel basis. Each channel may also be configured as DTE or DCE configuration.
1.6
General Purpose IO
Since some signals may not be used in all applications, the SIO4B 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 AuxC signals. This also allows signals from unused channels to be
available as general purpose IO.
1.7
Connector Interface
The SIO4BX provides a user IO interface through a front-side card edge connector. All four serial channels
interface through this high-density, 68 pin SCSI II type connector. Signals are grouped at the connector 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 SCSII connector
into four DB25 connectors (one per channel). A standard cable is also available with a single 68 pin SCSII
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.
