Intel 82540EP/EM Network Card User Manual


 
84 Software Developer’s Manual
PCI Local Bus Interface
4.1.3.1.3 Message Control
15 8 7 6 4 3 1 0
Reserved 64b
Multiple
Enable
Multiple
Capable
En
Bits
Read/
Write
Initial
Value
Description
0R 0b
MSI Enable. If 1b, Message Signaled Interrupts
a
are enabled and the
Ethernet controller generates Message Signaled Interrupts instead of
asserting INTA#.
3:1 R 0b
Multiple Message Capable. Indicates the number of messages
requested. The Ethernet controller only requests one message.
Register
Number of messages
0 1
1 2
2 4
3 8
4 16
5 32
6 Reserved
7 Reserved
6:4 RW 0b
Multiple Message Enable. Written by the system to indicate the
number of messages allocated. Since the Ethernet controller only
supports one message, the system should never write a value other
than 0b.
7R 1b
64-bit capable. A value of 1b indicates that the Ethernet controller is
capable of generating 64-bit message addresses.
15:8 R 0b Reserved. Reads as 0b.
a. Not applicable to the 82541xx or 82547GI/EI.