LAN9313 Datasheet, PDF (357/398 Pages) SMSC Corporation – Three Port 10/100 Managed Ethernet Switch with MII

Three Port 10/100 Managed Ethernet Switch with MII
Datasheet
13.3.4 Buffer Manager CSRs
This section details the Buffer Manager (BM) registers. These registers allow configuration and
monitoring of the switch buffer levels and usage. A list of the general switch CSRs and their
corresponding register numbers is included in Table 13.12.
13.3.4.1 Buffer Manager Configuration Register (BM_CFG)
Register #:
1C00h
Size:
32 bits
This register enables egress rate pacing and ingress rate discarding.
BITS
DESCRIPTION
31:7 RESERVED
6 BM Counter Test
When this bit is set, Buffer Manager (BM) counters that normally clear to 0
when read, will be set to 7FFF_FFFC when read.
5 Fixed Priority Queue Servicing
When set, output queues are serviced with a fixed priority ordering. When
cleared, output queues are serviced with a weighted round robin ordering.
4:2 Egress Rate Enable
When set, egress rate pacing is enabled. Bits 4,3,2 correspond to switch
ports 2,1,0 respectively.
1 Drop on Yellow
When this bit is set, packets that exceed the Ingress Committed Burst Size
(colored Yellow) are subjected to random discard.
Note:
See Section 13.3.3.26, "Switch Engine Ingress Rate Command
Register (SWE_INGRSS_RATE_CMD)," on page 340 for
information on configuring the Ingress Committed Burst Size.
0 Drop on Red
When this bit is set, packets that exceed the Ingress Excess Burst Size
(colored Red) are discarded.
Note:
See Section 13.3.3.26, "Switch Engine Ingress Rate Command
Register (SWE_INGRSS_RATE_CMD)," on page 340 for
information on configuring the Ingress Excess Burst Size.
TYPE
RO
R/W
R/W
R/W
R/W
R/W
DEFAULT
-
0b
0b
0b
0b
0b
SMSC LAN9313/LAN9313i
357
DATASHEET
Revision 1.2 (04-08-08)