FOXBORO FBM09輸入控制模塊
標(biāo)準(zhǔn)硬件電路僅為外圍設(shè)備保留1024字節(jié)的I/O尋址空間，從I/O$000到$3FF。所有標(biāo)準(zhǔn)的PC I/O外圍設(shè)備，如串行和并行端口、硬盤和軟盤驅(qū)動器控制器、視頻系統(tǒng)、實時時鐘、系統(tǒng)計時器和中斷控制器，都位于該I/O空間區(qū)域。BIOS正確初始化和配置所有這些寄存器；通常不需要直接調(diào)整這些I/O端口。I/O地址映射系統(tǒng)中斷中總結(jié)了分配的和用戶可用的I/O地址。除I/O端口地址外，I/O設(shè)備還具有單獨的硬件中斷線分配。分配給每個中斷線的是內(nèi)存中$00000至$003FF的256向量中斷表中的相應(yīng)中斷向量。表2-3列出了16個可屏蔽中斷和單個不可屏蔽中斷（NMI）及其功能。第43頁的表2-4詳細(xì)說明了中斷向量表中的向量。在第43頁的表2-4中，還定義了十六進(jìn)制和十進(jìn)制中斷數(shù)用于實模式和保護(hù)模式。
Standard hardware circuitry reserves only 1,024 byte of I/O addressing space from
I/O $000 to $3FF for peripherals. All standard PC I/O peripherals, such as serial and
parallel ports, hard and floppy drive controllers, video system, real-time clock, system
timers and interrupt controllers are addressed in this region of I/O space. The BIOS
initializes and configures all these registers properly; adjusting these I/O ports
directly is not normally necessary.
The assigned and user-available I/O addresses are summarized in the I/O Address
Map System Interrupts
In addition to an I/O port address, an I/O device has a separate hardware interrupt
line assignment. Assigned to each interrupt line is a corresponding interrupt vector in
the 256-vector interrupt table at $00000 to $003FF in memory. The 16 maskable
interrupts and the single Non-Maskable Interrupt (NMI) are listed in Table 2-3 along
with their functions. Table 2-4 on page 43 details the vectors in the interrupt vector
table. The interrupt number in HEX and decimal are also defined for real and
protected mode in Table 2-4 on page 43.
