Advanced Communication Board Developer Toolkit 

ABSTRACT:  DMA4.BAS

DMA4.BAS is an BASIC Language Direct Memory Access asynchronous test 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 or
WAIT/REQ on transmit for DMA channel 1. The "DMA always enabled" jumper on the
ACB must be jumpered. No additional jumpers are needed.

This program is set up for 19.2K baud, no parity, 8 data bits, and 1 stop bit.
This program will transmit or receive all characters using DMA. This program
is menu drive an will prompt your for the type of DMA transfer that you wish
to execute. 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 half duplex DMA.

Cables:

For asynchronous mode, only transmit and receive are needed. The program was
designed to  be used in a stand alone configuration with an asynchronous
terminal, however this program may be modified to work in a loop-back
configuration.

  Point to Point Cable:

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

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

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

    ACB-II
	SW1 1 On
	E? o-o o
	   o-o o
	E? ?? (DMA Enable)

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

Build Environment: Interpreter BASIC

Project Files : DMA4.BAS  (ASCII Text file)