ABB PFEA111-20 3BSE050090R20控制模块
PCI中断外围组件互连（PCI）本地总线上的中断是可选的，并定义为“电平敏感”，使用开放漏极输出驱动器断言为低（负真）。中断线INTx#的断言和取消断言与CLK异步。当请求设备驱动程序注意时，设备断言其INTx#行。一旦INTx#信号被断言，它将保持断言，直到设备驱动程序清除未决请求。当请求被清除时，设备取消断言其INTx#信号。PCI为单个功能设备定义了一条中断线，为多功能设备或连接器定义了最多四条中断线。对于单功能设备，只能使用INTA#，而其他三条中断线没有意义。第47页图2-1描述了与VME操作和PMC站点相关的VMIVME-7750中断逻辑。多功能设备上的任何功能都可以连接到任何INTx#线。中断引脚寄存器定义函数用于请求中断的INTx#行。如果设备实现单个INTx#线，则称为INTA#；如果它实现两条线，则称为INTA#和INTB#；等等
PCI Interrupts
Interrupts on Peripheral Component Interconnect (PCI) Local Bus are optional and
defined as “level sensitive,” asserted low (negative true), using open drain output
drivers. The assertion and de-assertion of an interrupt line, INTx#, is asynchronous to
CLK. A device asserts its INTx# line when requesting attention from its device driver.
Once the INTx# signal is asserted, it remains asserted until the device driver clears the
pending request. When the request is cleared, the device de-asserts its INTx# signal.
PCI defines one interrupt line for a single function device and up to four interrupt
lines for a multifunction device or connector. For a single function device, only INTA#
may be used while the other three interrupt lines have no meaning. Figure 2-1 on
page 47 depicts the VMIVME-7750 interrupt logic pertaining to VME operations and
the PMC site.Any function on a multifunction device can be connected to any of the INTx# lines.
The Interrupt Pin register defines which INTx# line the function uses to request an
interrupt. If a device implements a single INTx# line, it is called INTA#; if it
implements two lines, they are called INTA# and INTB#; and so forth.
