Filter
Top Products
GD82559ER — Networking Silicon
60
Datasheet
8.1.8 Receive Direct Memory Access 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.
8.1.9 Early Receive Interrupt
The Early Receive Interrupt register allows the 82559ER to generate an early interrupt depending
on the length of the frame. An early interrupt is indicated by the ER bit in the SCB Status Word and
the assertion of the INTA# signal.
8.1.10 Flow Control Register
The Flow Control Register contains the following fields:
•
Flow Control Command
The Flow Control Command field describes the action of the flow control process (for
example, pause, on, or off).
•
Flow Control Threshold
The Flow Control Threshold field contains the threshold value (in other words, the number of
free bytes in the Receive FIFO).
8.1.11 Power Management Driver Register
The 82559ER provides an indication in memory and I/O space that a wake-up event has occurred.
It is located in the PMDR.
29
Interrupt Enable.
When this bit is set to 1b by software, the 82559ER asserts an interrupt to
indicate the end of an MDI cycle.
28
Ready.
This bit is set to 1b by the 82559ER at the end of an MDI transaction. It should be
reset to 0b by software at the same time the command is written.
27:26
Opcode.
These bits define the opcode: 01 for MDI write and 10 for MDI read. All other values
(00 and 11) are reserved.
25:21
PHY Address.
This field of bits contains the PHY address (Default = 00001b).
20:16
PHY Register Address.
This field of bits contains the address of the PHY Register to be
accessed.
15:0
Data.
In a write command, software places the data bits in this field, and the 82559ER
transfers the data to the PHY unit. During a read command, the 82559ER reads these bits
serially from the PHY register (specified by bits 20:16), and software reads the data from this
location.
Bits Description
Table 11. Power Management Driver Register
Bits Default Read/Write Description
31 0b Read/Clear
Link Status Change Indication.
The link status change bit is set
following a change in link status and is cleared by writing a 1b to it.
30 0b Read
Not Supported, will always read as a ‘0’.