Chapter 3: Hardware Configuation and Installation
Manual Number: 00650-014-4
Page 3-3
Selecting and Setting the Base Address
The following section shows you how to select and set the address.
Selecting a Base Address
You need to select an unused segment of eight consecutive I/O addresses. The base address will be
the first address in this segment. The base address may be selected anywhere on a 8-bit boundary
within the I/O address range 200-3FF hex (excluding 1F0 through 1F8 in ATs) providing that it
does not overlap with other functions. The following procedure will show you how to select the
base I/O address.
1. Check the tables in FIGURES 3-2 AND 3-3 for lists of standard address assignments and then
check what addresses are used by any other I/O peripherals that are installed in your computer.
(Memory addressing is separate from I/O addressing, so there is no possible conflict with any
add-on memory that may be installed in your computer.) We urge that you carefully review the
address assignment table before selecting a card address. If the addresses of two installed
functions overlap, unpredictable computer behavior will result.
2. From this list (or using the FINDBASE program on diskette), select an unused portion of eight
consecutive I/O address. Note from the tables that the sections 280-2EF and 330-36F are
unused. This address space is good area to select a base address from. Also, if you are not
using a given device in listed in the tables, then you may use that base address as well. For
example, most computers do not have a prototype card installed. If your computer does not
have one, then base address 300 hex is a good choice for a base address.
3. Finally make sure that the base address you have chosen has the last digit as 0 or 8. This
insures that your base address is on an 8-byte boundary.
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