User manual

Page 4-1
Manual MPCI-DA12-16.Dh
Chapter 4: Address Selection
These cards use two I/O address spaces, one of 64 bytes and one of 256 bytes. The DACs occupy the
first 32 bytes of the first area. The digital I/O circuit uses the next 4 register locations. The
timer/counter chip uses 4 locations after that. The other 24 addresses are reserved. The 2nd I/O
address space of 256 bytes is used for software calibration data. These two I/O address spaces are
defined in the Port Address Selection Table 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 you 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.EXE utility program provided.
This utility will display a list of all of the ACCES cards detected on the PCI bus, the addresses
assigned to each function on each of the cards, and the respective IRQs.
Alternatively, some operating systems (Windows 9x and NT/2000) 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.
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 yourself, use the following information.
The Vendor ID for these cards is 494F. (ASCII for "IO")
The Device ID for the PCI-DA12-8 channel is 6CA8h.
The Device ID for the PCI-DA12-16 channel is 6CB0h.
The Device ID for the PCI-DA12-8 channel V is 6CA9h.
The Device ID for the PCI-DA12-16 channel V is 6CB1h.
The control / DAC / I/O / Counter/Timer base address is BaseAddresses[2] in the
PCI_COMMON_CONFIG structure, while the calibration base address is BaseAddresses[3].