TMT T71L6816A

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Preliminary T71L6816A
Sixteen-port 10/100 Switch
________________________________________________________
The T71L6816A is a sixteen-port 10/100Mbps dual speed ethernet switch integrated with
a built-in 2K entries of addr ess table and supports a 4Mb external SSRAM. T71L6816A is
also a high performance Fast-Ethernet switch with fully compliance with the IEEE802.3,
802.3u and 802.3x specifications. The T71L6816A can be implemented with external PHY chips
and 4Mb pipe-line SSRAM. By default, it is targeted for applications to the stand -alone
switch for low-cost SOHO and small enterprise market.
Features
l
Support sixteen 10/100 Ethernet ports with RMII interface.
l
External memory needed for 4Mb pipe-line SSRAM.
l
Incorporating with private output buffering scheme to prevent HOL (head of line) blocking.
l
Each port support priority-based queues with 4 levels and 802.1p QoS.
l
Wire-speed store-and-forward switching with low latency.
l
Automatic address learning with filtering of local frames or illegal frames.
l
Embedded 2K entries of address look-up table.
l
Support full/half duplex operations.
l
Support auto-negotiation via MDIO to detect speed and duplex status.
l
Serial EEPROM interface for auto-configuration for features.
l
Support IEEE802.3x flow control for full-duplex operation.
l
Support Back-Pressure flow control for half-duplex operation.
l
Support port-trunking mode to aggregate the bandwidth to provide the functions of load-sharing and
link backup.
l
Support broadcast storm control scheme.
l
Maximum 3 port-based VLAN groups can be defined by user.
l
Support port-based port monitoring/snooping defined by user.
l
Only one 50Mhz oscillator needed.
l
208-pin BGA, 3.3V with .18 µm CMOS technology.
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Preliminary T71L6816A
1. General Description
The T71L6816A is a highly integ rated sixteen-port 10Base-T/100Base-TX Ethernet switch
with RMII interface and is implemented in 0.18µm CMOS technology. The T71L6816A
supports a wide variety of switch features and provides flexible configurations at
maximum performance levels with lowest number of components.
This switch supports store-and-forward switching scheme with an external memory buffer
for incoming/outgoing packets and a built-in memory for address table. The T71L6816A use
the page-based memory architecture to fully utilize the packet buffer so that it can identify
up to 2048 different MAC addresses and enable the filtering and forwarding of packets
range from 64 bytes to 1522 bytes at the non-blocking wire speed, 148800 packets/sec at
64 bytes/packet.
The function modules integrated in T71L6816A include sixteen full -duplex media access
controller(MAC) with RMII interface to PHYs, one address resolution logic(ARL), one
flow control unit and one buffer management unit(BMU).
The T71L6816A supports IEEE 802.3x flow control in full -duplex mode and back-pressure
control in half-duplex mode. Also, the T71L6816A is fully compatible to the ability
for auto-negotiation with its link partner by periodically polling the status of PHYs.
The T71L6816A provides the port-based VLAN group funct ion to help users to isolate traffic
segment by segment for the sake of security and bandwidth saving. Maximum three VLANs
can be divide by users and it is suitable for application in small office or home.
The T71L6816A also supports the port-based trunking applications. With trunking enabled,
it is possible to aggregate up to four full-duplex links to form a single channel with
400Mbit/s data rate and to provide the load sharing effect.
The T71L6816A will also support the QoS requirement for some networks. With QoS enabled
in networks which is compatible to VLAN QoS, the T71L6816A will put incoming packets into
different priority output queues by checking the QoS field in their VLAN header. If the
user’s network do not support VLAN QoS, the T71L6816A still offers an alternative way
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Preliminary T71L6816A
to give different priority to incoming traffic from pre-defined source port.
Additionally, the T71L6816A provides the configuration ability through external EEPROM
to enable or disable functionality flexibly. However, the T71L6816A can operate well
without any external setting by default.
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Preliminary T71L6816A
2. Architecture
2.1 System Diagram
2.2 Block Diagram
.
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Preliminary T71L6816A
3. Functional Description
3.1 Reset
The T71L6816A will determine some function features chosen by the content of 24LC02
serial EEPROM which was loaded after power on reset. Also, the T71L6816A will write
the abilities derived from 24LC02 or internal default value if 24LC02 is not present
to connected PHY management registers via MDC/MDIO.
3.2 RMII Interface
The T71L6816A provides the low pin count RMII (Reduced Media Independent Interface)
interface capable of supporting 10/100 Mbps data rates between PHY and T71L6816A.
A single clock, 50MHz, sourced from an external clock input is needed for receive(RX)
and transmit(TX) to provide an independent 2-bit wide (di-bit) transmit and receive
data paths. In the case of the REFCLK is 10 times the data rate, namely, 100Mbps mode,
each data di -bit must be output on TXD[1:0] and input on RXD[1:0] for ten successive
REFCLK cycles.
RMII specification signals are listed below:
Signal Name
REFCLK
Direction
(with respect to
PHY)
Input
CRSDV
RXD[1:0]
TXEN
TXD[1:0]
Output
Output
Input
Input
Direction
Use
(with respect to
T71L6816A)
Input
Synchronous clock reference for Rx,
Tx and control interface
Input
Carrier sense / receive data valid
Input
Receive data
Output
Transmit enable
Output
Transmit data
3.3 Data Reception
The port will enter the receive-state when the CRSDV signal in the RMII interface is
asserted and t hen the RMII presents the received data in two-bit(di-bit) format that are
synchronous to the RMII reference clock, namely, REFCLK. The T71L6816A
will then try
to identify the occurrence of the SFD(Start Frame Delimiter) pattern “10101011”. Once
the SFD w as identified, all preamble data prior to SFD will be discarded and the frame
data will be forwarded and stored in the buffer of the switch.
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Preliminary T71L6816A
3.4 Illegal Frames
The T71L6816A will check the errors of incoming frames and discard all illegal packets
if any non -recovered error found. The kinds of errors include FCS error, illegal packet
length, symbol error and dribble error. However, for preamble error, the T71L6816A will
try to identify the SFD even if the preamble error happened and the packet will be dropped
only if the T71L6808A can not well identify the incoming packet.
3.4.1 FCS Error
The T71L6816A will generate the 4 bytes of CRC checksum through every incoming packets
and compare the checksum with the FCS field to identify if the packet is corrupt or not.
If it is found that the CRC checksum is not matched with the FCS field, the T71L6816A
will discard this packet due to something wrong on data transmission.
3.4.2 Alignment Error
The T71L6816A will discard the packets with the frame length is of no n-integer in octet
unit. Exactly, the kind of such packet usually results in CRC checksum error and is called
as alignment error.
3.4.3 Dribble Error
Dribble error is that the packets contains some extra bit after four bytes of FCS. The
T71L6816A will drop those packets because those packets are usually similar to the FCS
error.
3.4.4 Length of Frames
The T71L6816A can recognize the legal frame with length ranges from 64 bytes to 1522
bytes including four bytes of FCS. Any packet with length smaller than 64 bytes or larger
than 1522 bytes will be discarded.
3.5 Frame Forwarding
The first six bytes(DA) and the second six bytes(SA) of every incoming packet received
by T71L6816A will be retrieved and passed to Address Resolution Logic unit(ARL). The ARL
will use the SA to update the address table and use the DA to determine which destination
port the packet should be forwarded to by address table lookup.
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Preliminary T71L6816A
3.5.1 Unicast Forwarding
If the first bit of the DA is “0”, the packet is regarded as an unicast packet and the
ARL will use the DA as an key to search for a matched entry in address table by either
hashing algorithm or direct mapping method chosen by the configuration from EEPROM.
If an matched entry is found, the ARL will return a destination port number. If the port
number returned is within the same VLAN group but not the same of incoming port, the packet
will be forwarded to the destination port, otherwise it will be discarded. Also, if the
trunking scheme is enabled and the returned port is defined as a member of trunking group,
the real output port could be any one of the trunking ports and is dependent on trunking
scheme currently used.
If ARL can’t find any entry matched in address table, the packet will be regarded as an
broadcast packet and forwarded to other ports that belong to the same VLAN group of
the incoming port.
3.5.2 Multicast Forwarding
If the first bit of the DA is “1”, the packet is regarded as a multicast packet. The packet
will be forwarded to other ports that belong to the same VLAN group of the incoming port.
3.6 Data Transmission
According to the standard of IEEE 802.3, the T71L6816A will transmit all output packets
with a guaranteed minimum IPG(Inter Packet/Frame Gap) of 96BT(bit time) even if the
incoming packets have an IPG l ess than 96BT. However, the T71L6816A will drop excess
incoming packets which input continuously with smaller IPG than 96BT due to run out of
packet buffer and result in the packet loss. The 96BT should be 96ns for 10Mbps and 960ns
for 100Mbps.
During the transmit process, the T71L6816A will read the packet data from SSRAM and forward
it to the PHY device of the destination port in di-bit format. Also, the T71L6816A will
generate seven bytes of preamble(10101010) and SFD(10101011) prior to the frame data
followed by four bytes of FCS generated by T71L6816A automatically.
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Preliminary T71L6816A
3.7 Address
3.7.1 Address Learning
The T71L6816A has a on-chip address table with 2K entries to map the MAC address to
port -ID for the operation of packet forwarding engine. The T71L681 6A use either hash
algorithm or direct mapping to locate every entry and each entry contains the information
about incoming port number, partial MAC address and age timer.
The T71L6816A learns the MAC address of attached network devices by checking the so urce
MAC address(SA) of all incoming packets and acts as follows: If the SA is an unicast address
and can’t be found in address table, the T71L6816A will allocate an entry for this address
after this packet has been received with no error detected. If the SA was found in address
table, the T71L6806A will update the aging value of the corresponding entry to zero.
The T71L6816A will disable the learning process while the incoming packet is a PAUSE command
defined by IEEE 802.3x.
3.7.2 Address Aging
If the “ AgeEn” option configured in EEPROM is set, the T71L6816A will periodically check
every entry in address table and mark the entry as invalid if its aging timer is over
300 seconds. Once a entry is marked as invalid, this entry no longer be used for address
lookup until it is remarked as valid for new address.
3.8 Broadcast Storm Control
In general, the T71L6816A will forward the broadcast packets to other ports. It’s obviously
broadcast packets will use switch resources(bandwidth and available transmit queue) much
more than normal packets. In extreme case of unstable network with something wrong, it
may produce massive broadcast packets from one mal -functional device and results in the
crash of whole network, that is so-called broadcast storm.
If the “BRDCTRL” option configured in EEPROM is set, the T71L6816A provide a scheme to
prevent the broadcast storm by temporarily discarding the broadcast/multicast packets
if the number of those kind of packets exceeds the internal threshold.
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Preliminary T71L6816A
3.9 Back-off Algorithm
For every port that operates in half-duplex mode, the T71L6816A implements the truncated
exponential back-off algorithm compliant to IEEE 802.3 standard and the collision counter
based on per port will be restarted after every 16 consecutive collision. Th at is, the
T71L6816A will guarantee no packet loss if the times of consecutive collision is less
than 16.
3.10 Buffer Management
The T71L6816A provides an interface to the external 64x64K(4Mb) SSRAM which operates in
66MHz pipeline mode as the packet storage buffer. For purpose of efficiency, the T71L6816A
divide the 4Mb space to 1K pages and each page contains 512 bytes, therefore, maximum
3 pages or minimum 1 page is needed for every Ethernet packets.
3.11 Head-of-Line Blocking
One common requirement fo r Ethernet switch is to prevent the Head-of-Blocking problem.
In other words, in case of some ports under heavy traffic or congestion, the switch must
keep all other ports function well and don’t be affected by those congested ports.
The T71L6816A provide a alternative
way to achieve above requirement while customer
disable the flow control function. Say, the T71L6816A will first check the status of
the destination port of incoming packets, the packets will be dropped if the destined
port is congested and therefore the T71L6816A can reserve the finite spaces of the packet
buffer for other normal traffic ports.
3.12 Flow Control
3.12.1 Flow Control in Full Duplex Mode
The T71L6816A support the IEEE 802.3x flow control scheme in full duplex mode. The IEEE
802.3 define the format of pause frame as follow:
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Preliminary T71L6816A
By set the “FlowCtrl_En” in EEPROM for any specific port, The T71L6816A will check the
DA field of every incoming 64 -byte packet from the specific port to see if it is the address
“0x0180c2000001” or not. If it is the legal pause frame, the T71L6816A will hold the
data forwarding to the specific port for a time period depended on the value defined in
the pause timer field, otherwise the pause frame will be dropped if its format is illegal.
Also, if fl ow control is enabled for one port, the T71L6816A will automatically send out
one pause frame with pause timer “0xffff” to that port if the free pages of T71L6816A
drop below the low watermark.
3.12.1 Flow Control in Half Duplex Mode
The T71L6816A support the back pressure congestion control scheme in half duplex mode
with two different way, force-collision and force-carrier.
By set the “BackPress_En” in EEPROM, the T71L6816A will enable the back -pressure scheme
while the free pages of T71L6816A drop belo w the low watermark. If the internal resources
is low, The T71L6816A will force collision on the incoming packet if “BackMode” is set
to be ‘0’ and will occupy the carrier signal to stop packets receiving if “BackMode” is
set to be ‘1’.
3.13 Port-based VLAN
Sometimes users want to divide some segments on their network for some reasons such as
security or traffic. The T71L6816A provide the port -based VLAN(Virtual LAN) scheme to
divide the attached devices into maximum three different segments defined by con figuring
the EEPROM. Once different VLANs
were defined, the T71L6816A will forward the traffic
within the same VLAN segment and prevent them from flowing into ports not belong to the
same VLAN. So, users can isolate traffics between any two different VLANs but the common
port.
The T71L6816A use the VLAN_1/VLAN_2 fields defined in EEPROM to determine the effective
VLANs. That is, if any bit is set to ‘1’ in VLAN_1/VLAN_2, the corresponding port is
belonging to the VLAN group 1 or 2 and all other ports without inclusion in VLAN_1 or
VLAN_2, if exists, will form the third VLAN group. If one port belongs to more than one
VLAN group, it can receive all of the traffic within those VLAN groups.
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Preliminary T71L6816A
For example, if we write VLAN_1[15:8] as “0xff”, VLAN_1[7:0] as “0x00”, VLAN_2[15:8] as
“0x0f” and VLAN_2[7:0] as “0xf0”, the T71L6816A will recognize that VLAN group 1 contains
port 15 to port 8, VLAN group 2 contains port 11 to port 4 and VLAN group 3 contains
port 3 to port 0.
3.14 Port-based Trunking
Trunking scheme allows more than two ports to be connected in parallel between two switchs
to increase the traffic bandwidth. The T71L6816A supports up to four ports to form the
trunking backbone with four different mode to balance traffic load and maximum 400Mbps
of data rate is allowed. Also, the T71L6816A supports the link-redirect scheme for trunking
so that the T71L6816A can backup the link circuit automatically while one link
is down and restore the circuit after the circuit is up.
3.15 Port Monitoring
The T71L6816A provides the simple network monitoring scheme for persons who need to snoop
the traffic input from one specific port. By set “SnoopEn” bit in EEPROM, beyond of the
normal forwarding, the T71L6816A will make a duplication of any packet input from the
specified port defined in SPID and forward this copy to another specific port defined
in MPID, i.e., only one pair of snooping/monitoring port can be defined.
3.16 Queue Priority
There are four queues supported by T71L6816A with different priorities for every output
port. In general, the T71L6816A will treat all output packets as the same and put them
into one queue with lowest priority. However, if any packet which contains the 802.1Q
tagging with 3-bit priority value larger than 0 or comes from one port defi ned as high
priority is found, those packets will be put into other three output queues with more
higher priorities. The T71L6816A will use weighted round-robin method to serve every
output queue for each port that has packets in queues.
3.17 Interface of PHY management
The T71L6816A supports the PHY management through two signal lines, MDC and MDIO. The
T71L6816A will write physical abilities to the register 4 and register 5 of connected
PHYs and restart the auto -negotiation process by polling each PHYs with PHY address
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Preliminary T71L6816A
increasing from 01000b to 01111b after power on reset. The polling process will be
performing continuously to refresh the link status and the link partner’s abilities
such as speed, duplex and flow control until power off.
The following table shows the format of MDIO management frames:
Operation Preamble
Read
1……1
Write
1……1
ST
01
01
OP
10
01
PHYaddr
AAAAA
AAAAA
REGaddr
RRRRR
RRRRR
TA
Z0
10
DATA
DDDDDDDDDDDDDDDD
DDDDDDDDDDDDDDDD
IDLE
Z
Z
3.17 Interface of 24LC02
3.17.1 Block Diagram
The 24LC02 is an EEPROM chip providing 2K bits storage space with 2 -wire I2C interface.
After power on reset, the T71L6816A will use a sequential read command to load the
configuration settings defined by user in the 24LC02 and configure the features fr om
those settings for later normal operation. Once loading completed, the T71L6816A will
tri-state the two pins SDA and SCLK to be ready for on-line updating 24LC02 through the
parallel port.
As shown above, the user can run a simple program on WinNT/Win98 to configure the external
24LC02 through the parallel port which is popular in most personal/notebook computer.
The whole system can then be reset after the external 24LC02 been reconfigured to adapt
for different environments.
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Preliminary T71L6816A
3.17.2 Timing
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Preliminary T71L6816A
4. Pin Assignment
4.1 Pin Assignment
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Preliminary T71L6816A
4.2 Pin Description
Symbol
I/O type
Pin Number
Function
RMII Interfaces
REFCLK
I
166
Reference Clock.
Reference clock with 50MHz to provide the timing
reference for CRSDV, RXD[1:0], TXEN and TXD[1:0]
TXD_A[1:0]
O
180, 181
Transmit Data.
TXD[1:0] must operate synchronously with respect
TXD_B[1:0]
186, 187
TXD_C[1:0]
193, 194
to REFCLK and the TXD[1:0] will be accepted by
TXD_D[1:0]
199, 200
PHY transmission when TXEN is asserted.
TXD_E[1:0]
206, 207
TXD_F[1:0]
6, 7
TXD_G[1:0]
12, 13
TXD_H[1:0]
18, 19
TXD_I[1:0]
24, 25
TXD_J[1:0]
30, 31
TXD_K[1:0]
38, 39
TXD_L[1:0]
44, 45
TXD_M[1:0]
50, 51
TXD_N[1:0]
56, 57
TXD_O[1:0]
62, 63
TXD_P[1:0]
70, 71
RXD_A[1:0]
I
RXD_B[1:0]
182, 183
Receive Data.
RXD[1:0] must operate synchronously with respect
RXD_C[1:0]
189, 190
to REFCLK and the RXD[1:0] will transfer 2 -bit
RXD_D[1:0]
195, 196
data recovered from PHY to MAC on every REFCLK
RXD_E[1:0]
202, 203
period while CRSDV is high.
RXD_F[1:0]
208, 3
RXD_G[1:0]
8, 9
RXD_H[1:0]
14, 15
RXD_I[1:0]
20, 21
RXD_J[1:0]
26, 27
RXD_K[1:0]
34, 35
RXD_L[1:0]
40, 41
RXD_M[1:0]
46, 47
RXD_N[1:0]
52, 53
RXD_O[1:0]
58, 59
RXD_P[1:0]
66, 67
176, 177
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Symbol
Preliminary T71L6816A
I/O type
Pin Number
Function
RMII Interfaces (cont.)
TXEN_A ~ TXEN_P
O
179, 185, 192, 198,
Transmit Enable.
205, 5, 11, 17,
TXEN indicates the MAC is presenting 2-bit data
23, 29, 37, 43,
on TXD[1:0] for transmission.
49, 55, 61, 69
CRSDV_A ~ CRSDV_P
I
178, 184, 191, 197,
Carrier Sense / Receive Data Valid.
204, 4, 10, 16,
CRSDV indicates the PHY is presenting 2 -bit data
22, 28, 36, 42,
on RXD[1:0] for transmission.
48, 54, 60, 68
SRAM Interfaces
MEM_CLK
O
127
Memory Clock.
AEN_B
O
125
Address Enable.
GWE_B
O
124
Group Write Enable.
OE_B
O
123
Output Enable.
72, 73, 74, 75,
SRAM Data Bus.
SRAM_DATA[63:0]
I/O
76, 77, 78, 79,
80, 81, 82, 83,
84, 85, 86, 87,
91, 92, 93, 94,
95, 96, 97, 98,
99, 100, 101, 102,
103, 104, 105, 106,
129, 130, 131, 132,
133, 134, 135, 136,
137, 138, 139, 140,
141, 142, 143, 144,
145, 146, 147, 148,
149, 150, 151, 152,
153, 154, 155, 156,
161, 162, 163, 164
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Symbol
Preliminary T71L6816A
I/O type
Pin Number
Function
SRAM Interfaces (Cont.)
SRAM_ADDR[15:0]
O
107, 108, 109, 110,
SRAM Address Bus.
111, 112, 113, 114,
115, 116, 117, 118,
119, 120, 121, 122
Power Pins
VCC
158, 167
Power Pins for System.
3.3V DC power.
1, 32, 64, 89, 126,
Ground Pin.
160, 165, 169, 188
DC ground.
90, 157, 201
Power Pins for Core.
2, 33, 65, 88, 128,
GND
VDD
1.8V DC power.
Serial EEPROM Interfaces
SCLK
O
Serial Clock.
172
SCLK is used to synchronize the SDA and to be
pulled high internally.
SDA
I/O
Serial Data/Access.
173
Bi- directional serial data I/O line which is
pulled high internally.
PHY Management Interfaces
MDC
O
PHY Management Interface Clock.
174
The MDC provides the reference clock for shifting
serial data in/out from PHY device on rising
edges.
MDIO
I/O
175
PHY Management Interface Data I/O.
Bi-directional serial data contains information
which is read from or written to the PHY devices.
Test Pins
TEST
I
Test Mode Enable.
171
For normal use, this pin must be tire to low.
MOD[3:0]
I
107, 108, 109, 110
Test Mode Select.
For normal use, those p ins should be tired to low.
System Interfaces
RST
I
170
Reset.
Asynchronous active low reset signal.
SYSCLK
I
168
System Clock.
50MHz clock for system.
PLL_OFF
I
159
Phase-Loop-Lock enable/disable .
High to disable the internal PLL circuit.
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Preliminary T71L6816A
5. Reference Design
Please contact our sales for more detailed information.
6. Configuration of Serial EEPROM(24LC02)
6.1 Mapping of Configuration
Bit
Byte
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
7
6
BRDCTRL HashMode
5
4
3
2
1
0
AgeEn
BackMode SnoopEn Reserved Reserved Reserved
VLAN_1[15:8]
VLAN_1[7:0]
VLAN_2[15:8]
VLAN_2[7:0]
TrunkPort[1:0]
TrunkBase[1:0]
Reserved Reserved Reserved Reserved
MPID[3:0]
SPID[3:0]
Port-base setting for port 0
Port-base setting for port 1
Port-base setting for port 2
Port-base setting for port 3
Port-base setting for port 4
Port-base setting for port 5
Port-base setting for port 6
Port-base setting for port 7
Port-base setting for port 8
Port-base setting for port 9
Port-base setting for port A
Port-base setting for port B
Port-base setting for port C
Port-base setting for port D
Port-base setting for port E
Port-base setting for port F
PauseFrameSourceAddress[47:40]
PauseFrameSourceAddress[39:32]
PauseFrameSourceAddress[31:24]
PauseFrameSourceAddress[23:16]
PauseFrameSourceAddress[15: 8]
PauseFrameSourceAddress[ 7: 0]
PauseFrameOnCRC[31:24]
PauseFrameOnCRC[23:16]
PauseFrameOnCRC[15: 8]
PauseFrameOnCRC[ 7: 0]
PauseFrameOffCRC[31:24]
PauseFrameOffCRC[23:16]
PauseFrameOffCRC[15: 8]
PauseFrameOffCRC[ 7: 0]
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Change to products or specifications without notice.
P. 18
Publication Date:Jun. 2001
Revision:0.A
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Preliminary T71L6816A
6.2 Description of Configuration
BRDCTRL:
When 0, the broadcast storm control function is disabled
When 1, the broadcast storm control function is enabled
HashMode:
When 0, the address direct mapping algorithm is used
When 1, the address hashing algorithm is used
AgeEn:
When 0, the aging-out mechanism for address table is disable
When 1, the aging-out mechanism for address table is enabled
BackMode:
W h e n 0 , c h i p g e n e r ates jam sequence to any regulated port that start
to receive a frame while the switch becoming congested
When 1, chip generates carrier signal on any regulated port that
start to receive a frame while the switch becoming congested
SnoopEn:
When 0, the snooping function is disabled
When 1, the snooping function is enabled
(also refers to MPID/SPID)
TrunkPort[1:0]: When 00, no trunking
When 01, port0 and port1 are trunking ports
When 10, port0, port1 and port2 are trunking ports
When 11, port0, port1, port2 and port3 are trunking ports
TrunkBase[1:0]: When 00, based on (DA xor SA)
When 01, based on DA only
When 10, based on SA only
When 11, based on port
MPID[3:0]:
Port ID of port used to snoop other port snooped
SPID[3:0]:
Port ID of port to be snooped
VLAN_1[15:0]:
Port mapping of ports belong to VLAN group 1
VLAN_2[15:0]:
Port mapping of ports belong to VLAN group 2
Port-base setting format
Priority[1:0] 802_En SpeedMode DuplexMode MDIO_En
Priority[1:0]:
FlowCtrl_En BackPress_En
Port -base priority level, the ‘11’ means highest level and ‘00’
means lowest level
802_En:
IEEE802.1p format, ‘1’ means enable and ‘0’ means disable
SpeedMode:
Speed mode, ‘1’ for 100Mb and ‘0’ for 10Mb
DuplexMode: Duplex mode, ‘1’ for full-duplex and ‘0’ for half-duplex
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Change to products or specifications without notice.
P. 19
Publication Date:Jun. 2001
Revision:0.A
tm
MDIO_En:
TE
CH
Preliminary T71L6816A
Auto-negoiation from MDIO, ‘1’ means enable and ‘0’ means disable
FlowCtrl_En:
Flow control, ‘1’ means enable and ‘0’ means disable
BackPress_En:
Back-pressure mechanism, ‘1’ means enable and ‘0’ means disable
7. Temperature Limit Ratings
unit :
Parameter
C
Min.
Max.
-55
+125
0
70
Conditions
Min.
0.9*V CC
Storage temperature
Operating temperature
8. DC Characteristics
Symbol
Description
VOH
Output High Level Voltage
IOH = -8mA
VOL
Output Low Level Voltage
IOL = 8mA
VIH
Input High Level Voltage
VIL
Input Low Level Voltage
IINPUT
Typ.
Max.
Unit
VCC
V
0.1*VCC
V
0.5*V CC
VCC+0.5
V
-0.5
0.3*VCC
V
Input Current
VIN = VCC
-1.0
1.0
uA
IOZ
Output Leakage Current in Tri-State
VIN = VCC
-1.0
1.0
uA
ICC
Average Operating Supply Current
IOUT = 0mA
180
mA
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Change to products or specifications without notice.
P. 20
160
Publication Date:Jun. 2001
Revision:0.A
tm
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Preliminary T71L6816A
9. AC Characteristics
9.1 RMII Timing
unit : ns
Symbol
T1
Min.
-
Typ.
20
Max.
-
Reference clock high level period
Reference clock low level period
-
10
10
-
T4
setup time for TXEN and TXD[1:0]
4
-
-
T5
hold time for TXD[1:0]
2
-
-
T6
T7
setup time for CRSDV and RXD[1:0]
hold time for RXD[1:0]
4
2
-
-
T2
T3
Description
Reference clock period
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Change to products or specifications without notice.
P. 21
Publication Date:Jun. 2001
Revision:0.A
tm
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CH
Preliminary T71L6816A
9.3 PHY Management Timing
unit : ns
Symbol
T1
Description
MDC clock period
Min.
-
Typ.
SYSCLK*32
Max.
-
-
SYSCLK*16
SYSCLK*16
-
T2
T3
MDC clock high level period
MDC clock low level period
T4
hold time for MDIO on writing
10
-
T5
setup time for MDIO on writting
10
-
-
T6
hold time for MDIO on reading
waiting time required after reset
-
-
20
-
Treset
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P. 22
Publication Date:Jun. 2001
Revision:0.A