DA82562EM Intel, DA82562EM Datasheet - Page 47

• Manufacturer Part Number: DA82562EM
• Manufacturer: Intel

Specifications of DA82562EM

• Lead Free Status / Rohs Status: Not Compliant

6.3.2.3
6.3.2.4
Intel 8255x 10/100 Mbps Ethernet Controller Family Open Source Software Developer Manual
Table 14. SCB Command Word Bits Descriptions
Table 15. SCB General Pointer for the CU Command
SCB General Pointer
The SCB General Pointer is a 32-bit entity, which points to various data structures depending on
the command in the CUC or RUC field. The two tables below indicate what the SCB pointer means
for the different commands.
Statistical Counters
The 8255x provides information for network management by providing on-chip statistical counters
that track a variety of events associated with both transmit and receive. The counters are updated
by the device when it completes the processing of a frame. For example, after the completion of
transmitting a frame on the link or when receiving a frame, the counter is updated. The Statistical
Counters are reported to the software on demand by issuing the Dump Statistical Counters
command or the Dump and Reset Statistical Counters command in the SCB CUC field. The
counters are internal to the device and are listed in the table below.
Bit
Bits 18:16
RUC
Field
0
1
2
3
4
5
6
RU Command
NOP
RU Start
RU Resume
Reserved
RU Abort
Load HDS
Load RU Base
Symbol
RUC
Description
This field contains the RU Command. Valid values are:
000 NOP. NOP is a no operation command and does not alter current state of
unit.
001 RU Start. RU Start enables the receive unit. The pointer to the RFA must be
placed in the SCB General Pointer before using this command. The device pre-
fetches the first RFD in preparation of receiving incoming frames that pass its
address filtering.
010 RU Resume. The RU Resume command resumes frame reception (only
when in suspended state).
011 Receive DMA Redirect. This command is only valid for the 82558 and later
devices. The buffers are indicated by an RBD chain, which is pointed to by an
offset stored in the general pointer register (in the RU base).
100 RU Abort. The RU Abort command immediately stops RU receive
operation.
101 Load Header Data Size (HDS). After a load HDS command is issued, the
device expects to only find header RFDs or to be used in Receive DMA mode
until it is reset. This value defines the size of the header portion of the RFDs or
receive buffers. The HDS value is defined by the lower 14 bits of the SCB
General Pointer; thus, bits 15 through 31 should always be set to zeros when
using this command. The value of HDS should be an even non-zero number.
110 Load RU Base. The internal RU Base Register is loaded with the value that
was placed in the SCB General Pointer just before this command was issued.
SCB General Pointer
Don’t care
Pointer to first RFD in the Receive Frame Area
Don’t care
Don’t care
Don’t care
Header Data Size (Upper 18 bits must be zero)
32-bit Base Register for RU data structures
Host Software Interface
Added to
RU Base
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