24
Terminations
PCIODT_EN
1.5 K pull-down when
needed (see comments)
PCI Bus ODT Enable: is latched on the rising (deasserting) edge of
P_RST#, and determines when the PCI-X interface has On Die
Termination enabled valid on the secondary PCI bus only.
•
0 = ODT disabled on the secondary PCI bus. (Requires pull-down
resistor).
•
1 = ODT enabled on the secondary PCI bus. (Default mode).
This signal controls termination for the following signals:
S_AD[63:32], S_C/BE[7:4]#, S_PAR64, S_REQ64#, S_REQ[3:0]#,
S_ACK64#, S_FRAME#, S_IRDY#, S_DEVSEL#, S_TRDY#,
S_STOP#, S_PERR#, S_LOCK#, S_M66EN, S_SERR# and
XINT[3:0]#
NOTE: This signal is muxed onto signal A[20].
P_32BITPCI#
1.5 K pull-down when
needed (see comments)
Primary PCI-X Bus Width
: By default, identifies 80331 subsystem as
64-bit unless user attaches appropriate pull-down resistor.
0 = 32 bit wide bus. (Requires pull-down resistor).
1 = 64 bit wide bus. (Default mode).
NOTE: Muxed onto signal
A[2]
S_INT[D:A]#.
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_LOCK#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_SERR#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_TRDY#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_PERR#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_DEVSEL#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_FRAME#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_STOP#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_IRDY#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_AD[63:32]
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_C/BE[7:4]
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_PAR64
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_REQ64#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_ACK64#
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required.
S_M66EN
Refer to comments
•
When PCIODT_EN = 1 no external pull-up needed
•
When PCIODT_EN = 0, then 8.2 K pull-up is required when PCI
bus is to operate at 66 MHz. This signal is grounded for 33 MHz
operation.
Table 3.
Terminations: Pull-up/Pull-down (Sheet 2 of 4)
Signal
Pull-up or Pull-down
Resistor Value (in Ohms)
Comments
Summary of Contents for 80331
Page 1: ...Intel 80331 I O Processor Design Guide March 2005 Order Number 273823 003 ...
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Page 122: ...122 Intel 80331 I O Processor Design Guide Memory Controller ...
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