PM3351 Datasheet, PDF (217/268 Pages) PMC-Sierra, Inc – Single-Port 10/100 Mbit/s Ethernet Switch

DATA SHEET
PMC-970113
ISSUE 3
PM3351 ELAN 1X100
SINGLE PORT FAST ETHERNET SWITCH
DSHEAD control register from TRANSMIT to DROP in the case of excess collisions
(i.e. 16 consecutive collisions) and to update collision statistics.
Register 0x44 (cr36): TX_FIFO Control register (TXF_CSR)
Bit
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
Bit 7
Bit 6
Bits 5:0
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Function
Unused
AUTO_INC_MODE
SW_WRITE_MODE
FRAME_MODE
BSWP_RWDATA
BSWP_RRDATA
WR_MCFRAME
RD_MCFRAME
EN_TXDONE_INTR
FIX_CRC
MAX_PKTS[5:0]
Default
0
1
0
0
0
0
0
0
1
0
0x1E
AUTO_INC_MODE:
Puts theTX_FIFO into auto increment mode. This feature, if set (1), results in
having various write and read pointers auto incremented for Switch Processor
frame accesses to the data ram and MAC control frame rams (that is, if the
FRAME_MODE bit is also set). This relieves firmware from having to keep
track of the read and write pointers. Affected ram address pointers: wr_ptr
and rd_ptr (for TX_FIFO data ram) and mcwptr (for MAC Ctrl frame ram).
SW_WRITE_MODE:
controls whether the TXF_DATAH and TXF_DATAL register is configured for
read or write of either the TX_FIFO data ram or MAC Ctrl ram. If this bit is
set (1) then data written to the TXF_DATAH/L registers will be written to the
selected ram; if the bit is clear (0) then data read from the selected ram may
be read by the Switch Processor in the TXF_DATAH/L register.
FRAME_MODE:
defines the type of access with respect to the data ram. If this bit is set (1)
then write accesses to the TX_FIFO data ram by the Switch Processor are
taken to be Ethernet Frame data and are formatted in the rams accordingly.
If this bit is clear (0) then the Switch Processor may arbitrarily read and write
bytes in either the data ram or the MAC control frame ram. In normal switch
applications this bit is set (1) during the firmware initialization sequence.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE 211