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2 SunSAI/P User’s Guide • November 1998
Board Operation
The SunSAI/P board is a multi channel intelligent Serial Asynchronous Interface
board for computers incorporating the PCI bus standard.
The heart of the SunSAI/P board is a 32-bit RISC processor. The board has 128 KB of
dual-ported high-speed RAM used for program code and data buffering. The
SunSAI/P board supports “preset” throughput speeds of up to 115K bps for each
asynchronous port.
The processor and dual ported RAM relieves your computer of the burden of
managing the serial ports. The computer can transfer large blocks of data directly to
the memory on the board, then move on to other tasks while the board sends the
data out the serial ports one character at a time. Similarly, the board receives input
data and stores it in buffers in its dual ported RAM, so the computer only needs to
check periodically to see if data is available.
The dual ported RAM is memory which is accessible for read and write operations
by both the board and the computer. To the computer, the dual ported RAM looks
exactly like its own memory, and can be accessed by the same high speed memory
referencing commands it uses for its internal memory. This means that a block of
data that may take a number of seconds for the SunSAI/P board to receive or
transmit to the outside world can be transferred between the board and the
computer in mere microseconds.
The SunSAI/P board’s dual ported RAM is mapped into a 4 Megabyte unused area
in the host computer’s memory address space.
Customer Assistance
Be sure to read the Release Notes that may be included with this software. The
Release Notes contain information not available at this manual’s press time.
For assistance in the United States, please call 1-800-USA-4SUN.
For information on how to get the latest patches and patch revision, please visit the
SunSolve
sm
website at
http://sunsolve.sun.com
, or contact your local Sun
Service provider. For additional information, access Sun on the World Wide Web at
http://www.sun.com
and select Sales and Service.