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57
Networking Silicon — GD82559ER
8. Control/Status Registers
8.1 LAN (Ethernet) Control/Status Registers
The 82559ER’s Control/Status Register (CSR) is illustrated in the figure below.
NOTE:
In Figure 23 above, SCB is defined as the System Control Block of the 82559ER, and PMDR is defined
as the Power Management Driver Register.
SCB Status Word:
The 82559ER places the status of its Command and Receive units
and interrupt indications in this register for the CPU to read.
SCB Command Word:
The CPU places commands for the Command and Receive units in
this register. Interrupts are also acknowledged in this register.
SCB General Pointer:
The SCB General Pointer register points to various data structures
in main memory depending on the current SCB Command word.
PORT Interface:
The PORT interface allows the CPU to reset the 82559ER, force the
82559ER to dump information to main memory, or perform an
internal self test.
Flash Control Register:
The Flash Control register allows the CPU to enable writes to an
external Flash.
EEPROM Control Register:
The EEPROM Control register allows the CPU to read and write to
an external EEPROM.
D31 Upper Word D16 D15 Lower Word D0 Offset
SCB Command Word SCB Status Word 00H
System Control Block General Pointer 04H
PORT 08H
EEPROM Control Register Flash Control Register 0CH
Management Data Interface (MDI) Control Register 10H
Receive Direct Memory Access Byte Count 14H
PMDR Flow Control Register Early Receive Int 18H
Reserved General Status General Control 1CH
Reserved 20H
Reserved 24H
Reserved 28H
Reserved 2CH
Reserved 30H
Reserved 34H
Reserved 38H
Reserved 3CH
Figure 23. 82559ER Control/Status Register