Information

PCI Express Interface Controller
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
Freescale Semiconductor 14-71
14.4.6.11 PCI Express Slot Capabilities Update Register (PEX_SLCAP_UPDATE)
The PCI Express slot capabilities update register shown in Figure 14-87 is used to set the values to the PCI
Express slot capabilities register in the PCI Express configuration header (offset 0x60). It can be used
when the device is configured as an End Point to make the correct slot information available to the
upstream device. This register has to be programmed before setting the config-ready bit in the PCI Express
configuration ready register so that the host reads the correct information during enumeration.
Table 14-85 shows the PCI Express slot capabilities update register fields description.
14.4.6.12 PCI Express Configuration Ready Register
The PCI Express configuration ready register, shown in Figure 14-88, indicates configuration complete
status to the transaction layer. The transaction layer handles configuration requests from external hosts
only after the CFG_READY bit is set. All the configuration requests received from external hosts before
the CFG_READY bit is set are completed with configuration request retry status (CRS). To ensure that the
Offset 0x490 Access: R/W
31 30 29 17 16 15 14 7 6 5 4 3 2 1 0
R —
PSN SPLS SPLV HPC HPS PIP AIP MRL PCP ABP
W
Reset0 0 0 00000000000 0 0 0 00001111 1 0 0 0 0 0 0
Figure 14-87. PCI Express Slot Capabilities Update Register
Table 14-85. PCI Express Slot Capabilities Update Register Fields Description
Bits Name Description
31–30 — Reserved
29–17 PSN Physical Slot Number. Physical slot number attached to the port.
16–15 SPLS Slot Power Limit Scale. Specifies the scale used for the slot power limit value. The range of
values is as follows:
00 1.0x
01 0.1x
10 0.01x
11 0.001x
14–7 SPLV Slot power limit value. In combination with the slot power limit scale value, specifies the upper
limit on power supplied by slot. The power limit (in Watts) is calculated by multiplying the value
in this field by the value in the slot power limit scale field.
6 HPC Hot plug capable
5 HPS Hot plug surprise
4 PIP Power indicator present
3 AIP Attention indicator present
2 MRL MRL sensor present
1 PCP Power controller present
0 ABP Attention button present