AN00016.TXT

Advanced Communication Board Developer's Toolkit 1995


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Subject: ACB-II Full Duplex DMA Modification.


This application note describes a modification that will allow the ACB-II
to transfer data using full duplex DMA. A standard ACB-II can will only
use half duplex DMA. This modification is valid for the ACB-II revision
D or later. If there are any questions or comments, please contact
technical support at the numbers listed in the README.TXT file located in
the root directory of this diskette.

Detailed Description of Modification:

1.  Install a wire jumper at position D and E on header E5.

	E5
	    A o o
	    B o o
	    C o o
	    D o-o   <-	Add Jumpers here
	    E o-o   <-	Add Jumpers here
	    F o o
	    G o o
	    H o o
	    I o o
	    J o o
	    K o o
	    L o o

2.  Move the jumper on the left side of E3 and move the jumper on the right
    to the top two pins.

	E3
	    o o o
	    o o-o

3.  Install a 74LS08 in the unpopulated position labeled U10.

To test the modification, use the test program on TDMA.EXE in the UTIL
directory on this diskette. Assuming a base address of 238 Hex, type the
following to test the modified ACB-II:

C:\>TDMA /b:238 /d:1 /t:1 /r:3 /l <ENTER>