- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄1912 > DP83848CVVX/NOPB (National Semiconductor)TXRX ETHERNET PHYTER 48LQFP PDF資料下載
參數(shù)資料
| 型號： | DP83848CVVX/NOPB |
| 廠商： | National Semiconductor |
| 文件頁數(shù)： | 26/86頁 |
| 文件大?。?/td> | 0K |
| 描述： | TXRX ETHERNET PHYTER 48LQFP |
| 產(chǎn)品培訓(xùn)模塊： | PHYTER® Family |
| 標(biāo)準(zhǔn)包裝： | 1 |
| 系列： | * |
| 其它名稱： | DP83848CVVX/NOPBDKR |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁當(dāng)前第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁
31
www.national.com
DP
83
84
8
C
4.3.2 Smart Squelch
The smart squelch is responsible for determining when
valid data is present on the differential receive inputs. The
DP83848C implements an intelligent receive squelch to
ensure that impulse noise on the receive inputs will not be
mistaken for a valid signal. Smart squelch operation is
independent of the 10BASE-T operational mode.
The squelch circuitry employs a combination of amplitude
and timing measurements (as specified in the IEEE 802.3
10BSE-T standard) to determine the validity of data on the
twisted pair inputs (refer to Figure 10).
The signal at the start of a packet is checked by the smart
squelch and any pulses not exceeding the squelch level
(either positive or negative, depending upon polarity) will
be rejected. Once this first squelch level is overcome cor-
rectly, the opposite squelch level must then be exceeded
within 150 ns. Finally the signal must again exceed the
original squelch level within a 150 ns to ensure that the
input waveform will not be rejected. This checking proce-
dure results in the loss of typically three preamble bits at
the beginning of each packet.
Only after all these conditions have been satisfied will a
control signal be generated to indicate to the remainder of
the circuitry that valid data is present. At this time, the
smart squelch circuitry is reset.
Valid data is considered to be present until the squelch
level has not been generated for a time longer than 150 ns,
indicating the End of Packet. Once good data has been
detected, the squelch levels are reduced to minimize the
effect of noise causing premature End of Packet detection.
4.3.3 Collision Detection and SQE
When in Half Duplex, a 10BASE-T collision is detected
when the receive and transmit channels are active simulta-
neously. Collisions are reported by the COL signal on the
MII. Collisions are also reported when a jabber condition is
detected.
The COL signal remains set for the duration of the collision.
If the PHY is receiving when a collision is detected it is
reported immediately (through the COL pin).
When heartbeat is enabled, approximately 1
s after the
transmission of each packet, a Signal Quality Error (SQE)
signal of approximately 10-bit times is generated to indi-
cate successful transmission. SQE is reported as a pulse
on the COL signal of the MII.
The SQE test is inhibited when the PHY is set in full duplex
mode. SQE can also be inhibited by setting the
HEARTBEAT_DIS bit in the 10BTSCR register.
4.3.4 Carrier Sense
Carrier Sense (CRS) may be asserted due to receive activ-
ity once valid data is detected via the squelch function.
For 10 Mb/s Half Duplex operation, CRS is asserted during
either packet transmission or reception.
For 10 Mb/s Full Duplex operation, CRS is asserted only
during receive activity.
CRS is deasserted following an end of packet.
4.3.5 Normal Link Pulse Detection/Generation
The link pulse generator produces pulses as defined in the
IEEE 802.3 10BASE-T standard. Each link pulse is nomi-
nally 100 ns in duration and transmitted every 16 ms in the
absence of transmit data.
Link pulses are used to check the integrity of the connec-
tion with the remote end. If valid link pulses are not
received, the link detector disables the 10BASE-T twisted
pair transmitter, receiver and collision detection functions.
When
the
link
integrity
function
is
disabled
(FORCE_LINK_10 of the 10BTSCR register), a good link is
forced and the 10BASE-T transceiver will operate regard-
less of the presence of link pulses.
end of packet
start of packet
VSQ-(reduced)
VSQ-
VSQ+(reduced)
VSQ+
<150 ns
>150 ns
Figure 10. 10BASE-T Twisted Pair Smart Squelch Operation
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DP83848HSQ/NOPB | IC TXRX ETHERNET PHYTER 40-LLP |
| DP83848YB/NOPB | IC TXRX ETHERNET PHYTERA 48-LQFP |
| DRM4000-N00-232 | DRM 4000 MODULE |
| DRM4000L-N00-232 | MODULE DEAD RECKONING RS-232 |
| DS100BR111SQE/NOPB | IC REPEATER 10.3GBPS 2CH 24LLP |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DP83848EVV/NOPB | 功能描述:以太網(wǎng) IC RoHS:否 制造商:Micrel 產(chǎn)品:Ethernet Switches 收發(fā)器數(shù)量:2 數(shù)據(jù)速率:10 Mb/s, 100 Mb/s 電源電壓-最大:1.25 V, 3.45 V 電源電壓-最小:1.15 V, 3.15 V 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-64 封裝:Tray |
| DP83848EVVX/NOPB | 功能描述:以太網(wǎng) IC 10/100 ETHERNET PHY RoHS:否 制造商:Micrel 產(chǎn)品:Ethernet Switches 收發(fā)器數(shù)量:2 數(shù)據(jù)速率:10 Mb/s, 100 Mb/s 電源電壓-最大:1.25 V, 3.45 V 電源電壓-最小:1.15 V, 3.15 V 最大工作溫度:+ 85 C 封裝 / 箱體:QFN-64 封裝:Tray |
| DP83848H | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:DP83848H PHYTER㈢ Mini - Extreme Single 10/100 Ethernet |
| DP83848H_07 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:DP83848H PHYTER㈢ Mini - Extreme Single 10/100 Ethernet |
| DP83848H_08 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:DP83848H PHYTER? Mini - Extreme Single 10/100 Ethernet Transceiver |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。