The PCI Bridge

Interrupt pins –INT1 to –INT4 are configured as output ports and conventionally associated with doorbell bits DB3 to DB6 in the PowerSpan. Each doorbell bit, when set, will activate its corresponding interrupt pin (level = 0), and when reset will deactivate it (level =1).

Interrupt pin –INT5 is used as an input. Its state can be read in the PowerSpan Interrupt status register. As an interrupt source, it was decided not to map it to any interrupt output, so it will not generate interrupts. As an interrupt output pin, it was decided not to associate it to any interrupt source.

Interrupt pins –INTA and –INT0, used for true interrupt functions, have several other interrupt sources, such as Mailboxes interrupts, DMA interrupts, I²O interrupts, PCI bus or local bus error interrupts, etc. They are conventionally associated with a doorbell bit for software activation capability.

Table 1-21. PowerSpan Interrupt Pin Usage

PowerSpan Pin

Doorbell

Dir

Signal Name

Usage

 

 

 

 

 

±,17$

'%￿

2

±,17$

,QWHUUXSW￿IURP￿WKH￿￿￿￿￿￿WR￿WKH￿3&,￿+RVW￿FRQWUROOHG￿E\￿

 

 

 

 

VRIWZDUH￿E\￿WKH￿3RZHU48,&&￿,,￿

 

 

 

 

 

±,17￿

'%￿

2

±,17363

,QWHUUXSW￿IURP￿WKH￿SRZHU6SDQ￿WR￿WKH￿3RZHU48,&&￿,,￿

 

 

 

 

LQWHUUXSW￿LQSXW￿±,54￿

 

 

 

 

 

±,17￿

'%￿

2

±,17567

)ODVK￿PRGH￿￿:KHQ￿WKLV￿RXWSXW￿LV￿VHW￿WR￿￿￿￿WKH￿

 

 

 

 

3RZHU48,&&￿,,￿LV￿SXW￿LQ￿UHVHW￿￿LWV￿EXVVHV￿DUH￿WUL￿

 

 

 

 

VWDWHG￿￿WKH￿￿￿[￿EXV￿LV￿SDUNHG￿IRU￿WKH￿3RZHU6SDQ￿DQG￿

 

 

 

 

WKH￿VSHFLDO￿DGGUHVV￿WUDQVODWLRQ￿PRGH￿RQ￿WKH￿)/$6+￿

 

 

 

 

PHPRU\￿LV￿HQDEOHG￿

 

 

 

 

 

±,17￿

'%￿

2

±363B,17￿￿

:KHQ￿WKLV￿SLQ￿LV￿VHW￿WR￿￿￿￿WKH￿3RZHU48,&&￿,,￿

 

 

 

±+5(6(7￿

KDUGZDUH￿UHVHW￿VLJQDO￿LV￿DFWLYDWHG￿￿)RU￿,63￿(3/'￿

 

 

 

,63',

SURJUDPPLQJ￿￿WKLV￿SLQ￿VHUYHV￿DOVR￿DV￿￿6HULDO￿'DWD￿,Q￿￿

 

 

 

 

VLJQDO￿

 

 

 

 

 

±,17￿

'%￿

2

±363B,17￿￿

:KHQ￿WKLV￿SLQ￿LV￿VHW￿WR￿￿￿￿WKH￿3RZHU48,&&￿,,￿

 

 

 

±65(6(7￿

VRIWZDUH￿UHVHW￿VLJQDO￿LV￿DFWLYDWHG￿￿)RU￿,63￿(3/'￿

 

 

 

,6302'(

SURJUDPPLQJ￿￿WKLV￿SLQ￿VHUYHV￿DOVR￿DV￿￿0RGH￿￿VLJQDO￿

 

 

 

 

 

±,17￿

'%￿

2

±363B,17￿￿

￿)RU￿,63￿(3/'￿SURJUDPPLQJ￿￿WKLV￿SLQ￿VHUYHV￿DV￿

 

 

 

,63&.

￿6HULDO￿&ORFN￿￿VLJQDO￿

 

 

 

 

 

±,17￿

±

,

±363B,17￿￿

)RU￿,63￿(3/'￿SURJUDPPLQJ￿￿WKLV￿SLQ￿VHUYHV￿DV￿

 

 

 

,63'2

￿6HULDO￿'DWD￿2XW￿￿VLJQDO￿

 

 

 

 

 

PCI to Local Interrupt (ATN)

The PowerSpan Interrupt pin –INT0 is used to control the PCI-to-Local Interrupt (renamed ATN (Attention) in the software examples).

20

Interphase Corporation