MTD655 Datasheet, PDF (9/18 Pages) List of Unclassifed Manufacturers – 5 Port 10M/100M Hub With 2 port Switch

MYSON
TECHNOLOGY
MTD655
2.0 MTD655 FUNCTIONAL DESCRIPTIONS
The MTD655 is conformed to IEEE802.3 chapter 9 and IEEE802.3u clause 27 specifications. The
MTD655 provides 4 Redused MII interfaces, 1 MII interface and an embedded two port switch to con-
struct a 10M/100M dual speed Hub application. Two Inter-Bus are also provided for stackable 10M/
100M dual speed Hub application. The MTD655 functions are described as followmtd655s:
2.1 Repeat and data handling
4 independent RMII ports and 1 MII port integrated with IEEE802.3 chapter 9 and IEEE802.3u clause
27 repeater functions simultaneously. MTD655 embedded two Hub cores (10M and 100M) ,and each
dedicated RMII or MII interface port can get per port’s speed information from per port speed input pin,
and then MTD655 will switch individual port to their appropriated Hub core functions (10M or 100M).
The MTD655 receive packets from each RMII and MII ports, and redirect port’s input packet to 10M or
100M Hub core according each port’s speed. The internal IEEE802.3 chapter 9 or IEEE802.3u clause
27 repeater main state machine will starts to repeat the input packet to all ports except the input port. If
larger than or equal to two ports have input packet simultaneously, this will be treated as a collision, and
MTD655 will assert an arbitrary JAM pattern to all ports’output until collision event disappear and net-
work is idle.
2.2 Partition
The MTD655 provides 10M/100M auto partition/reconnection functions to guarantee the network seg-
ment performance by means of dectecting a consecutive collisions. Each dedicated RMII or MII port
has implement a individual 10M/100M auto partition/reconnection state machine. If port’s consecutive
collision number over or equal to CClimit (10M CClimit default is 32, 100M CClimit default is 64), this
port will be partitioned. Reconnection will occurs after a larger than 512 bit time packet was received or
transmitted from this partitioned port without any collision.
When port is under partition state, MTD655 will not accept any input messages from this port (just mon-
itor input message), but will continue output repeated messages to this partition port.
Some new partition criterions are also implement, such as long_collision_partition event,
jabber_partition event. In 10M/100M partition state machine, longer than 1024 bit time continueous col-
lision will force port enter partition state. In 100M partition state machine, if port enter jabber_on state,
this port will be partitioned. In 10M, jabber_partition function is not implemented.
2.3 Jabber
The jabber protect function is used to prevent an illegally long packet reception. After the MTD655
received a longer than 65536 +/- 6.25% bit times packet, this receive port‘s receive/transmit path will be
inhibited until carrier is no longer detected.
2.4 MII Setting
Due to HUB is an half duplex device, the MTD655 need to force all connected phsical devices to work
in half duplex environment. The MTD655 will setting all PHY’s SMI register 4’s half/full duplex bit during
power on, and than restart auto-negotiation procedure to work in half duplex mode, and the PHY’s
device ID should be set by PCB maker from 5’h07 - 5’h0b(port0-4).
2.5 Inter-Bus Interface
Two Inter-Bus Interface are provided by the MTD655, One is 10M Inter-Bus Interface, the other is 100M
Inter-Bus Interface. The Inter-Bus interface is designed for stackable hub application. For each domain,
up to 4 MTD655s can be stacked through this Inter-Bus without any external arbitration logic. The Inter-
Bus Interface includes IMASTER, IDATA (100M: use IDAT<3:0>, 10M: use only IDAT), REQOUT,
REQIN0-2, ICLK, IACKB, ICOLB pins. IMASTER decide which MTD655 can arbitrate the Inter-Bus,
and only one MTD655’s IMASTER can be tie high in a stackable Hub. IDATA are synchronous with
ICLK. The MTD655 output REQOUT to inform Inter-Bus Interface that it need the Inter-Bus right. When
IACKB is asserted by Inter-Bus master after REQOUT asserted, the MTD655 which asserted
REQOUT will get the bus right and put the transmit data into IDATA. If the MTD655 did not assert
9/18
MTD655 Revision 2.0 17/03/2000