3X38FTR Datasheet, PDF (32/64 Pages) Agere Systems – OCTAL-FET (Fast Ethernet Transceiver) for 10Base-T/100Base-TX/FX

3X38FTR 208-Pin SQFP
OCTAL-FET for 10Base-T/100Base-TX/FX
Preliminary Data Sheet
September 2000
Functional Description (continued)
The 3X38 supports a preamble suppression mode as
indicated by a 1 in bit 6 of the basic mode status regis-
ter (BMSR, address 01h). If the station management
entity (i.e., MAC or other management controller)
determines that all PHYs in the system support pream-
ble suppression by reading a 1 in this bit, then the sta-
tion management entity need not generate preamble
for each management transaction. The 3X38 requires a
single initialization sequence of 32 bits of preamble fol-
lowing powerup/hardware reset. This requirement is
generally met by the mandatory pull-up resistor on
MDIO or the management access made to determine
whether preamble suppression is supported. While the
3X38 will respond to management accesses without
preamble, a minimum of one IDLE bit between man-
agement transactions is required as specified in IEEE
802.3U.
Interrupt
The 3X38 implements interrupt capability that can be
used to notify the management station of certain
events. Interrupt requested by any of the eight PHYs is
combined in this pin. It generates an active-high inter-
rupt pulse on the MASK_STAT_INT output pin when-
ever one of the interrupt status registers (register
address 31) becomes set while its corresponding inter-
rupt mask register is unmasked. Reading the interrupt
status register (register 31) shows the source of the
interrupt and clears the interrupt output signal.
100Base-X Module
The 3X38 implements 100Base-X compliant PCS and PMA and 100Base-TX compliant TP-PMD as illustrated in
Figure 12. Bypass options for each of the major functional blocks within the 100Base-X PCS provide flexibility for
various applications. 100 Mbits/s PHY loopback is included for diagnostic purposes.
RXCLK
FOSD±
RXD[1:0]
CRS_DV
TXEN
TXD[1:0]
RXD[3:0]
4B/5B
DECODE
BYP_4B5B
BYP_ALIGN
CRS
RXDV
RXEN
RX STATE MACHINE
RYP_SCR
100BASE-X RECEIVER
TPIN±
COL
TXCLK
TXEN
TXER
BYP_4B5B
TX STATE MACHINE
BYP_SCR
BYP_ALIGN
MLT-3
STATE
MACHINE
10/100
TX
DRIVER
TPOUT±
100BASE-X TRANSMITTER
Figure 12. 100Base-X Data Path
5-7519(F).a.r1
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Lucent Technologies Inc.