STE10A Datasheet, PDF (23/82 Pages) STMicroelectronics – PCI 10/100 Ethernet controller with integrated PHY (3.3V)

STE10/100A
Functional description
Data conversions of NRZI to NRZ and serial to parallel
After the data is recovered, it will be passed to the NRZI-to-NRZ converter to produce a
125MHz serial bit stream. This serial bit stream will be packed to parallel 5B type for further
processing. The NRZI to NRZ conversion may be bypassed by clearing ENRZI (bit 7 of
XR10) to 0.
De-scrambling and decoding of 5B/4B
The parallel 5B type data is passed to the de-scrambler and 5B/4B decoder to restore it to
its original MII nibble representation.
Carrier sensing
The carrier sense (CRS) signal is asserted when the transceiver detects any 2 non-
contiguous zeros within any 10-bit boundary of the receiving bit stream. CRS is de-asserted
when ESD code-group or Idle code-group is detected. In half duplex mode, CRS is asserted
during packet transmission or receive; in full duplex mode, CRS is asserted only during
packet reception.
10BASE-T transmission operation
The parallel-to-serial converter, Manchester Encoder, Link test, Jabber and the transmit
wave-shaper and line driver functions described in the section of “Wave-Shaper and Media
Signal Driver” of “100BASE-T Transmission Operation” are also provided for 10BASE-T
transmission. Additionally, Collision detection and SQE test for half duplex application are
provided.
10BASE-T receive operation
Carrier sense function, receiving filter, PLL for clock and data recovery, Manchester
decoder, and serial to parallel converter functions are provided to support 10BASE-T
reception.
Loop-back operation of transceiver
● The transceiver provides internal loop-back (also called transceiver loop-back)
operation for both 100BASE-TX and 10BASE-T operation. The loop-back function can
be enabled by setting XLBEN (bit 14 of XR0) to 1. In loop-back mode, the TX± and RX±
lines are isolated from the media. The transceiver also provides remote loop-back
operation for 100BASE-TX operation. The remote loop-back operation can be enabled
by setting ENRLB (bit 9 of XR10) to 1.
● In 100BASE-TX internal loop-back operation, the data is routed from the transmit
output of NRZ-to-NRZI converter and looped back to the receive input of NRZI-to-NRZ
converter.
In 100BASE-TX remote loop-back operation, data is received from RX± pins and
passed through the receive path to the output of the data and clock recovery section,
and then looped back to the input of the NRZI-to-MLT3 converter and out to the
medium via the transmit line drivers.
In 10BASE-T loop-back operation, the data is passed through the transmit path to the
output of the Manchester encoder and then looped back into the input of the phase lock
loop circuit in the receive path.
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