Adaptec 1737100 Programmer Manual - Page 74

AIC-6915 Ethernet LAN Controller Programmer's Manual AIC-6915 Address Space A device on a PCI bus can be accessed using different PCI command types. The AIC-6915 can be accessed using Memory, I/O and Configuration commands. The 512-KByte address space is mapped to a base address defined by the operating system at boot time. The first 256-KBytes are also mapped to the expansion ROM space. In addition, the first 256-bytes of the second 256-KBytes are mapped to Configuration and I/O space and are directly accessed using one of the three PCI command types: Memory, I/O, and Configuration. Indirect I/O commands can be used for accessing the rest of the space. The AIC-6915 address space is divided to a number of major subspaces with different characteristics. Table 7-2 describes these subspaces. Name Reserved Status Registers Ethernet Fifo General_Registers Internal_Functional_ Registers Ext_General_Purpose_ Registers [[E]EP]ROM Table 7-2. AIC-6915 PCI Address Space Byte Address Range Size (bytes) Description 0x70084 0x7FFFF 64K Reserved for future use 0x70000 0x70083 Contains status registers. 0x60000 0x6FFFF 64K Used for accessing the internal receive/transmit data FIFO 0x50100 0x5FFFF Used for accessing physical chip registers, Serial EPROM, MAC registers and additional status/debug registers. 0x50000 0x500FF 64K Used for accessing the PCI configuration header and AIC-6915 internal functional registers that are mostly accessed by the software driver during normal chip operation. 0x40000 0x4FFFF 64K Used for connecting an external device to the AIC-6915. 0x00000 0x3FFFF 256K Read/Write external [E]EPROM. This sub-space is mapped also to the PCI Expansion ROM space. AIC-6915 PCI Address Map Figure 7-1 illustrates the AIC-6915 PCI address map. 7-2