Intel CONTROLLERS 413808 - Manual (Page 765)

Intel ® 413808 and 413812 I/O Controllers in TPER Mode
October 2007 Developer’s Manual
Order Number: 317805-001US 765
Clocking and Reset—Intel ® 413808 and 413812
17.1.1.2.1 Central Resource Mode (PCIX_EP# = ‘1’)
When operating as the Central Resource ( PCIX_EP# = 1), the bus PCI bus operating
frequency and default value in ATUX PCSR[19:16] is determined based on the sampling
of PCIXCAP , P_MODE2 , M66EN , PCIXM1_100#
, and
PCIXM2_100#
.
When PCI Express* REFCLK is the primary clock source, the CR_FREQ[1:0] pins can
be used to control the operating frequency of an external clock source for the PCI bus.
The CR_FREQ[1:0] value can be changed by setting bits[19:16] in the ATUX PCSR
register (offset x074).
Table 506. PCI Bus Frequency Initialization
a
a. 81348 does not support PCI-X 533Mhz.
P_PCIXCAP P_MODE2 P_M66EN PCIXM1_100
#
PCIXM2_100
#
PCI Bus Mode PCI Bus Frequency
ATUX
PCSR[19:16
]
< 0.11VCC – b
b. A ‘–’ in table indicates value is a ‘don’t care’ for computing bus mode/frequency. All signals must still be pulled to a valid logic
level.
Ground – – PCI 33 MHz 1111
< 0.11VCC –
Not
connected
– – PCI 66 MHz 1111
< 0.6VCC &
> 0.11 VCC
GND – – –
PCI-X
Mode 1
66 MHz 1110
< 0.6VCC &
> 0.11VCC
VCC – – GND
PCI-X
Mode 2
100 MHz
(PCI-X 200 MHz)
0101
< 0.6VCC &
> 0.11VCC
VCC – – VCC
PCI-X
Mode 2
133 MHz
(PCI-X 266 MHz)
0100
< 0.89VCC &
> 0.6VCC
– – – –
PCI-X
Mode 1
66 MHz 1110
> 0.89VCC – – GND –
PCI-X
Mode 1
100 MHz 1101
> 0.89VCC – – VCC –
PCI-X
Mode 1
133 MHz 1100
Table 507. CR_FREQ[1:0] Encoding
ATUX PCSR[19:16] (PCIX Init
Pattern)
ATUX PCSR[10]
(P_M66EN)
CR_FREQ[1:0
]
Bus Frequency Bus Mode
1111 0 11 33 MHz Conventional PCI
1111 1 10 66 MHz Conventional PCI
1110 – 10 66 MHz PCI-X
1101 – 01 100 MHz PCI-X
1100 – 00 133 MHz PCI-X