ADLINK PCI-7251 - Manual (Page 37)

Registers 29
3 Registers
Detailed descriptions of the registers are specified in this chapter.
This information is useful for programmers who wish to control the
card with low-level programming. However, we suggest users fully
understand the PCI interface before starting any low-level pro-
gramming. In addition, the contents of this chapter will also help
users understand how to use the software drivers to configure this
card.
3.1 PCI PnP Registers
This PCI card functions as a 32-bit PCI target device to any mas-
ter on the PCI bus. There are three types of registers: PCI Config-
uration Registers (PCR), Local Configuration Registers (LCR) and
725X registers.
The PCR, which is PCI-bus specification compliant, is initialized
and controlled by the Plug and Play (PnP) PCI BIOS. Users may
obtain more information on the PCI BIOS specification to better
understand the operation of the PCR. Please contact PCISIG to
acquire PCI interface specifications.
The PCI bus controller PCI-9050 is provided by PLX Technology
Inc. (www.plxtech.com). For more information about the LCR,
please visit PLX Technology’s web site to download relative infor-
mation. It is not necessary for users to fully understand the details
of the LCR if the software library provided is used. The PCI PnP
BIOS assigns the base address of the LCR. The assigned address
is located at an offset of 14h from the PCR.
The 725X registers are discussed in the next section. The base
address, which is also assigned by the PCI PnP BIOS, is located
at an offset of 18h from the PCR. Therefore, users can read the
address 18h from the PCR to obtain its base address by using the
BIOS function call. Do not attempt to modify the base address and
interrupt that have been assigned by the PCI PnP BIOS, it may
cause resource conflicts with your system.