Intel GD82559ER User Manual

Page of 94
GD82559ER — Networking Silicon
58
Datasheet
MDI Control Register: 
The MDI Control register allows the CPU to read and write 
information from the PHY unit (or an external PHY component) 
through the Management Data Interface.
Receive DMA Byte Count: 
The Receive DMA Byte Count register keeps track of how many 
bytes of receive data have been passed into host memory via DMA.
Flow Control Register:
This register holds the flow control threshold value and indicates 
the flow control commands to the 82559ER.
PMDR:
The Power Management Driver Register provides an indication in 
memory and I/O space that a wake-up interrupt has occurred. The 
PMDR is described in further detail in 
Section 8.1.11, “Power 
Management Driver Register” on page 60
.
General Control:
The General Control register allows the 82559ER to enter the deep 
power-down state and provides the ability to disable the Clockrun 
functionality. The General Control register is described in further 
detail in 
Section 8.1.12, “General Control Register” on page 61
.
General Status:
The General Status register describes the status of the 82559ER’s 
duplex mode, speed, and link. The General Status register is 
detailed in 
Section 8.1.13, “General Status Register” on page 61
.
8.1.1
System Control Block Status Word
The System Control Block (SCB) Status Word contains status information relating to the 
82559ER’s Command and Receive units. 
Bits
Name
Description
15
CX
Command Unit (CU) Executed. The CX bit indicates that the CU has 
completed executing a command with its interrupt bit set.
14
FR
Frame Received. The FR bit indicates that the Receive Unit (RU) has 
finished receiving a frame.
13
CNA
CU Not Active. The CNA bit is set when the CU is no longer active and in 
either an idle or suspended state.
12
RNR
Receive Not Ready. The RNR bit is set when the RU is not in the ready 
state. This may be caused by an RU Abort command, a no resources 
situation, or set suspend bit due to a filled Receive Frame Descriptor.
11
MDI
Management Data Interrupt. The MDI bit is set when a Management Data 
Interface read or write cycle has completed. The management data interrupt 
is enabled through the interrupt enable bit (bit 29 in the Management Data 
Interface Control register in the CSR).
10
SWI
Software Interrupt. The SWI bit is set when software generates an 
interrupt.
9
ER
Early Receive. The ER bit is used for early receive interrupts.
8
FCP
Flow Control Pause. The FCP bit is used as the flow control pause bit.
7:6
CUS
Command Unit Status. The CUS field contains the status of the Command 
Unit.
5:2
RUS
Receive Unit Status. The RUS field contains the status of the Receive Unit.
1:0
Reserved
These bits are reserved and should be set to 00b.