3

Registers Format

Detailed descriptions of the register's format are specified in this

chapter. This information is quite useful for the programmers who wish to handle the card through low-level programming. However, we suggest users understand more about the PCI interface before beginning any low-level

programming. In addition, the contents of this chapter can help users understand how to use a software driver to manipulate this card.

3.1PCI PnP Registers

This PCI card functions as a 32-bit PCI target device to any master on the PCI bus. There are three types of registers: PCI Configuration Registers (PCR), Local Configuration Registers (LCR) and PCIDAC 082 registers.

The PCR, which is compliant with PCI-bus specifications, is initialized and controlled by the plug & play (PnP) PCI BIOS. User's can study the PCI BIOS specification to understand the operation of the PCR.

The PCI bus controller PCI-9050 is provided by PLX technology Inc. (www.plxtech.com). For more detailed information of LCR, please visit PLX technology’s web site to download relative information. It is not necessary for users to understand the details of the LCR if you use the software library. The PCI PnP BIOS assigns the base address of the LCR. The assigned address is located at offset 14h of PCR.

The PCIDAC 0812 registers are shown in the next section. The base address, which is also assigned by the PCI PnP BIOS, is located at offset 18h of PCR. Therefore, users can read the 18h of PCR to know the base address

by using the BIOS function call.

Please do not try to modify the base address and interrupt which assigned by the PCI PnP BIOS, it may cause a resource conflict in your system.

20 ∙ Registers Format