LAN9218I-MT SMSC, LAN9218I-MT Datasheet - Page 60
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LAN9218I-MT
Manufacturer Part Number
LAN9218I-MT
Description
Ethernet ICs Indust Hi Perfrm Single-Chip
Manufacturer
SMSC
Type
Single Chip MAC and PHY Controllerr
Datasheet
1.LAN9218I-MT.pdf
(133 pages)
Specifications of LAN9218I-MT
Ethernet Connection Type
10 Base-T, 100 Base-TX
Minimum Operating Temperature
- 40 C
Mounting Style
SMD/SMT
Product
Ethernet Controllers
Number Of Transceivers
1
Standard Supported
802.3, 802.3u
Data Rate
10 Mbps, 100 Mbps
Supply Voltage (max)
3.3 V
Supply Voltage (min)
0 V
Supply Current (max)
69 mA
Maximum Operating Temperature
+ 85 C
Package / Case
TQFP-100
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
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Manufacturer:
Standard
Quantity:
1 981
Company:
Part Number:
LAN9218I-MT
Manufacturer:
SMSC
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Quantity:
20 000
Revision 2.7 (03-15-10)
4.3.4
4.3.5
4.3.6
4.4
4.4.1
4.4.2
Descrambling
The descrambler performs an inverse function to the scrambler in the transmitter and also performs
the Serial In Parallel Out (SIPO) conversion of the data.
During reception of IDLE (/I/) symbols. the descrambler synchronizes its descrambler key to the
incoming stream. Once synchronization is achieved, the descrambler locks on this key and is able to
descramble incoming data.
Special logic in the descrambler ensures synchronization with the remote PHY by searching for IDLE
symbols within a window of 4000 bytes (40us). This window ensures that a maximum packet size of
1514 bytes, allowed by the IEEE 802.3 standard, can be received with no interference. If no IDLE-
symbols are detected within this time-period, receive operation is aborted and the descrambler re-starts
the synchronization process.
The descrambler can be bypassed by setting bit 0 of register 31.
Alignment
The de-scrambled signal is then aligned into 5-bit code-groups by recognizing the /J/K/ Start-of-Stream
Delimiter (SSD) pair at the start of a packet. Once the code-word alignment is determined, it is stored
and utilized until the next start of frame.
5B/4B Decoding
The 5-bit code-groups are translated into 4-bit data nibbles according to the 4B/5B table. The SSD,
/J/K/, is translated to “0101 0101” as the first 2 nibbles of the MAC preamble. Reception of the SSD
causes the PHY to assert the internal RX_DV signal, indicating that valid data is available on the
Internal RXD bus. Successive valid code-groups are translated to data nibbles. Reception of either the
End of Stream Delimiter (ESD) consisting of the /T/R/ symbols, or at least two /I/ symbols causes the
PHY to de-assert the internal carrier sense and RX_DV.
These symbols are not translated into data.
Data to be transmitted comes from the MAC layer controller. The 10Base-T transmitter receives 4-bit
nibbles from the MII at a rate of 2.5MHz and converts them to a 10Mbps serial data stream. The data
stream is then Manchester-encoded and sent to the analog transmitter, which drives a signal onto the
twisted pair via the external magnetics.
The 10M transmitter uses the following blocks:
10M Transmit Data across the internal MII bus
The MAC controller drives the transmit data onto the internal TXD BUS. When the controller has driven
TX_EN high to indicate valid data, the data is latched by the MII block on the rising edge of TX_CLK.
The data is in the form of 4-bit wide 2.5MHz data.
Manchester Encoding
The 4-bit wide data is sent to the TX10M block. The nibbles are converted to a 10Mbps serial NRZI
data stream. The 10M PLL locks onto the external clock or internal oscillator and produces a 20MHz
10Base-T Transmit
MII (digital)
TX 10M (digital)
10M Transmitter (analog)
10M PLL (analog)
High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX and Industrial Temperature Support
DATASHEET
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SMSC LAN9218i
Datasheet