Advanced Communication Board Developer Toolkit 

ABSTRACT:  DMA1.C

DMA1.C is an Direct Memory Access asynchronous loop-back program. The base
address is 238 Hex and no IRQ is used for this test. DMA jumpers on the ACB
card should be set for WAIT/REQ on receive for DMA channel 1 and DTR/REQ on
transmit for DMA channel 3.  The "DMA always enabled" jumper on the ACB must
be "ON". No additional jumpers are needed. To build the program, the
ACB.C and the DMA.C files must be built/included from the \LIBRARY directory.

This program is set up for 19.2K bps, no parity, 8 data bits, and 1 stop bit.
This program will transmit and receive all characters using DMA. The program
will terminate when the DMA channel 1 has reached Terminal Count or any key
on the keyboard is pressed. Keep in mind that this example is a very simple
DMA program. A combination of DMA and interrupts yields the highest throughput
on an ACB adapter.

Please note that this example uses full duplex DMA. The ACB-II only supports
half duplex DMA. Either the program or your ACB-II should be modified to use
this program. Please refer to the \APP_NOTE directory on this diskette for
details on ACB-II full duplex modifications.

Cables:

For asynchronous mode, only transmit and receive are needed. The program was
designed to  be used in a stand alone loop-back configuration, however this
program may be modified to work with another PC with an ACB card or with an
asynchronous COM: port card installed.

  For Loop-Back Plug:

     For Single Ended (RS-232, MIL-188/114)
	Connect Tx to Rx

     For Differential Interface (RS-530, V.35, MIL-188/C, etc.)
	Connect Tx+ to  Rx+
	Connect Tx- to  Rx-

Dip-Switch and Jumpers:

Note: If a jumper is not listed, that jumper is not relevant to this example.

    ACB-104             ACB-530             ACB-VI
	SW1 2,3,4,8 On      SW1 2,3,4,8 On      SW1 2,3,4,8 On
	E1 A,B,D            E2 0|0000           E9 A,B
			    E4 000000||         E15 00||0000
			    E5 00||0000         E16 000000||

    ACB-III             ACB-IV              ACB-V
	SW2 2,3,4 On        SW1 2,3,4 On        SW1 2,3,4 On
	E4 1,4              E3 1,4              E2 1,4
	E5 1,4,6            E5 1,4,6,7          E1 1,4,6,7
	E9 1


    Note 1: The ACB-II does not support Full-Duplex DMA (See file
	    APP_NOTE.TXT)

    Note 2: The ACB-MP and MAXPORT do not support DMA transfers.

Build Dependencies:

DMA1.C
 * ACB.OBJ
 * ACB.H
 * DMA.OBJ
 * DMA.H
 * Z8530.H

 * Denotes that files are located in the \LIBRARY directory.