Omega Vehicle Security DAQ-16 user manual I/O Base Address Selection

2.4Base Address

The DAQ-16 uses 16 consecutive I/O address locations in the range 0 to 0FFFFH. Two six-position switches (SW1 and SW2) are used to select the base address. SW1 controls address lines A15 - A10, and SW2 controls A9 - A4. Address lines A3 - A0 are used internally by the DAQ-16 to select which register to access.

When selecting a base address for the DAQ-16, an address selection switch in the "OFF" position corresponds to an address bit of "1" while a switch in the "ON" position corresponds to an address bit of "0". The base address of the DAQ-16 must be set on a 16 byte boundary, meaning A3 - A0 are "0". The address of the DAQ-16 as shipped from the factory is 0300H. This setting and other examples are shown in the Figure 2-5.

	x	x	x	x	x	x
O	1	2	3	4	5	6
N

A A A A A A 15 14 13 12 11 10

SW1

SW2

	x	x	x	x	x	x
O	1	2	3	4	5	6
N

A A A A A A 9 8 7 6 5 4

0000			xxxx	Hex
		0000 : 0
	Bit=0 Bit=1	0001 : 1
		0010 : 2
		0011 : 3
		0100 : 4

		0			3					0
0	0	0	0	0	0	1	1	0	0	0	0

O 1 2 3 4 5 6	O 1 2 3 4 5 6
N	N

Example1: Base I/O Address = 0300H

		6				A					D
0	1	1	0	1	0		1	0	1	1	0	1
O 1 2		3	4	5 6			O 1	2	3 4		5 6
N							N

00101 : 5

0110 : 6

0111 : 7

1000 : 8

1001 : 9

1010 : A

1011 : B

1100 : C

01101 : D

1110 : E

1111 : F

Example 2: Base I/O Address = 6AD0H

Figure 2-5. I/O Base Address Selection

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