Intel SDS2 2 64-bit, 66-MHz PCI Subsystem, 1.2 P32-A Arbitration, P32-A Arbitration Connections

I/O Subsystem Intel® Server Board SDS2

Table 5. P32-A Configuration IDs

IDSEL Value	Device
18	ATI RAGE XL Video Controller
19	Intel® 82550 Fast Ethernet Controller 1
20	Intel 82550 Fast Ethernet Controller 2
24	PCI Slot 3
25	PCI Slot 4
31	CSB5 South Bridge

4.1.1.2P32-A Arbitration

P32-A supports seven PCI masters (ATA RAGE XL, two Intel 82550s, PCI masters from slots 3 and 4, CSB5, and HE-SL). All PCI masters must arbitrate for PCI access, using resources supplied by the HE-SL. The following table defines the arbitration connections.

Table 6. P32-A Arbitration Connections

Baseboard Signals	Device
REQ_VGA / GNT_VGA	ATI* RAGE XL Video Controller
D_PCIREQL1 / D_PCIGNTL1	Intel® 82550 Fast Ethernet Controller 1
D_PCIREQL2 / D_PCIGNTL2	Intel® 82550 Fast Ethernet Controller 2
D_PCIREQL3 / D_PCIGNTL3	PCI Slot 3
D_PCIREQL4 / D_PCIGNTL4	PCI Slot 4
D_PCIREQL5 / D_PCIGNTL5	CSB5 South Bridge

4.1.264-bit, 66-MHz PCI Subsystem

There are two 64-bit, 66-MHz PCI busses directed through the CIOB20 I/O Bridge. Both segments support full-length, full-height PCI cards. The PCI cards must meet the PCI specification for height, inclusive of cable connections and memory. The two PCI segments are peer buses.

4.1.2.1Device IDs (IDSEL)

Each device under the PCI hub bridge has its IDSEL signal connected to one bit of AD [31:16], which acts as a chip select on the PCI bus segment in configuration cycles. This determines a unique PCI device ID value for use in configuration cycles. The following tables show the bit to which each IDSEL signal is attached for P64-B and P64-C devices, and corresponding device description.

12	Revision 1.2
Order Number:	A85874-002