
Applied Micro Circuits Corporation
6195 Lusk Blvd., San Diego, CA 92121 (619) 450-9333
5-11
PCI CONTROLLER
S5933
DEVICE SPECIFICATION
5.9
INTERRUPT CONTROL/STATUS
REGISTER (INTCSR)
Register Name:
Interrupt Control and Status
PCI Address Offset: 38h
Power-up value:
00000000h
Attribute:
Read/Write (R/W),
Read/Write_One_Clear (R/WC)
Size:
32 bits
This register provides the method for choosing which
conditions are to produce an interrupt on the PCI bus
interface, a method for viewing the cause of the inter-
rupt, and a method for acknowledging (removing) the
interrupt’s assertion.
Interrupt sources:
Write Transfer Terminal Count = zero
Read Transfer Terminal Count = zero
One of the Outgoing mailboxes (1,2,3 or 4)
becomes empty
One of the Incoming mailboxes (1,2,3 or 4)
becomes full.
Target Abort
Master Abort
Figure 5-6. Interrupt Control/Status Register
31
0
15 14
12
8
4
Bit
Value
16
21
23
24
FIFO and Endian Control*
0
Read Transfer
Complete (R/WC)
Write Transfer
Complete (R/WC)
Incoming Mailbox
Interrupt (R/WC)
Outgoing Mailbox
Interrupt (R/WC)
Interrupt Asserted (RO)
Target Abort (R/WC)
Master Abort (R/WC)
0
0 0 0
D4-D0 Outgoing Mailbox
(Goes empty)
D4=Enable Interrrupt
D3-D2=Mailbox #
0 0=Mailbox 1
0 1=Mailbox 2
1 0=Mailbox 3
1 1=Mailbox 4
D1-D0=Byte #
0 0=Byte 0
0 1=Byte 1
1 0=Byte 2
1 1=Byte 3
D12-D8 Incoming Mailbox (R/W)
(Becomes full)
D12=Enable Interrupt
D11-D10=Mailbox
0 0=Mailbox 1
0 1=Mailbox 2
1 0=Mailbox 3
1 1=Mailbox 4
D9-D8=Byte #
0 0=Byte 0
0 1=Byte 1
1 0=Byte 2
1 1=Byte 3
Interrupt on Write
Transfer Complete
Interrupt on Read
Transfer Complete
Interrupt Source (R/W)
Enable & Selection
Actual Interrupt
Interrupt Selection
* See Figure 4-7