FOXBORO FCM100E以太网模块
此空间可用于设置保护模式PCI到VMEbus窗口（也称为PCI从属映像）。BIOS还将在该区域映射基于PCI的板载NVRAM、计时器和看门狗计时器。**该空间可以分配为共享内存（例如，在基于奔腾处理器的CPU和VMEbus Master之间）。请注意，如果加载了PMC板，则扩展BIOS可能位于该区域/O端口映射与桌面系统一样，VMIVME-7750包含特殊的输入/输出指令，用于访问驻留在I/O寻址空间（与内存寻址空间分离且不同）中的I/O外围设备。I/O地址空间中的位置称为端口。当CPU解码并执行I/O指令时，它在线A00至A15上产生一个16位I/O地址，并用M/I/O控制线识别I/O周期。因此，CPU包括一个独立的64Kbyte I/O地址空间，它可以作为字节、字或长字访问。
This space can be used to set up protected mode PCI-to-VMEbus windows (also referred
to as PCI slave images). BIOS will also map on-board PCI based NVRAM, Timers and
Watchdog Timers in this area.
** This space can be allocated as shared memory (for example, between the Pentium
processor-based CPU and VMEbus Master). Note that if a PMC board is loaded, the
expansion BIOS may be placed in this area./O Port Map
Like a desktop system, the VMIVME-7750 includes special input/output instructions
that access I/O peripherals residing in I/O addressing space (separate and distinct
from memory addressing space). Locations in I/O address space are referred to as
ports. When the CPU decodes and executes an I/O instruction, it produces a 16-bit
I/O address on lines A00 to A15 and identifies the I/O cycle with the M/I/O control
line. Thus, the CPU includes an independent 64 Kbyte I/O address space, which is
accessible as bytes, words or longwords.
