=

AST RESEARCH, INC.         TECHNICAL BULLETIN # 1261                7-26-95

=


DSP DIGISPEACH FUNCTIONS ERRATICALLY ON ASCENTIA XXXN NOTEBOOKS


PROBLEM

When the DSP Digispeach device is attached to the parallel port of an 
Ascentia 900N notebook, the sound device will fail at random intervals.


CAUSE

The "Functional Specification" for the device that controls the parallel port 
in the Ascentia XXXN notebook computer states that the "PACK" signal from the 
external device should be at least 2.5 usec. in width.  This signal 
specification complies with IEEE std. 1284-1994.  Any device that provides 
a pulse whose width is less than specified is likely to experience random 
failures.


SYSTEMS AFFECTED

All AST Ascentia XXXN notebook computers, or any system that uses the VLSI 
Technologies VL82C144 peripheral controller chip.


SOLUTION

At present there is no solution to this issue and this bulletin is provided 
for informational purposes only.  We suggest you contact the manufacturer of 
the incompatible device to see if there is currently a fix or if a fix is 
planned to alleviate the problem.

The parallel port on the Ascentia XXXN complies with the IEEE, ECP, and EPP 
specifications.  AST has made the VLSI chip's timing requirements available to 
the manufacturers of any incompatible hardware that have been reported to us.