Manual PCI-IDIO-16
11
Chapter 3: Address Selection
This card uses I/O addresses offset from the base address assigned by the PCI bus. The address spaces
are defined in the programming section of this manual.
PCI architecture is Plug-and-Play. This means that the BIOS or Operating System determines the
resources assigned to PCI cards rather than the user selecting those resources with switches or jumpers.
As a result, you cannot set or change the card's base address or IRQ level. You can only determine what
the system has assigned.
To determine the base address that has been assigned, run the PCIFind utility program. This utility will
display a list of all the cards detected on the PCI bus, the addresses assigned to each function on each of
the cards, and the respective IRQs.
Alternatively, Windows systems can be queried to determine which resources were assigned. In these
operating systems, you can use either PCIFind, or the Device Manager utility from the System Properties
Applet of the control panel. The card is installed in the Data Acquisition class of the Device Manager list.
Selecting the card, clicking Properties, and then selecting the Resources Tab will display a list of the
resources allocated to the card.
The PCI bus supports 64K of I/O address space, so your card's addresses may be located anywhere in
the 0000h to FFFFh range. The card occupies eight consecutive 8 bit registers in I/O address space.
PCIFind uses the Vendor ID and Device ID to search for your card, then reads the base address and
IRQ. If you want to determine the base address and IRQ without using PCIFind, use the following
information:
The Vendor ID code is 494F (ASCII for "I/O")
The Device ID code for the card is 0x0DC8
An example of how to locate PCI card resources is provided with in the PCI\SOURCE directory, under
your installation directory. This code runs in DOS, and uses the PCI defined interrupt BIOS calls to query
the PCI bus for card specific information. You will need the Device ID and Vendor ID listed above to use
this code.
