TNETX3150A datasheet(20/113 Pages) TI1

20 / 113 page

TNETX3150/TNETX3150A

ThunderSWITCH™ 15-PORT 10-/100-MBIT/S ETHERNET™ SWITCH

SPWS027F – FEBRUARY 1997 – REVISED SEPTEMBER 1997

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

RX filtering of non-cut-through frames

The TNETX3150/TNETX3150A filters RX frames (CRC, alignment, jabber, etc.) that contain errors when

operating in store-and-forward mode. A frame that might be cut-through can be non-cut-through if its destination

is busy. If it contains any error, it is filtered. The error is recorded in the relevant statistic counter, with all used

buffers being recovered and returned to the free queue.

deserialization

The raw data is deserialized before further processing. The data is formed into 64-bit words. The received data

is synchronized with the internal clock of the TNETX3150/TNETX3150A.

receive control

Receiver control is partitioned into two blocks:

The frame-control block schedules all receive operations (detection and removal of the preamble,

extraction of the addresses and frame length, data handling, and CRC checking. Also included is a

jabber-detection timer to detect greater-than-maximum-length frames being received on the network.

The FIFO-control block places the received data into the FIFO buffers, while also detecting and flagging

erroneous data conditions in the flag byte.

TNETX3150/TNETX3150A MXXDUPLEX terminals

The MXXDUPLEX terminals are implemented as inputs with active pulldown circuitry, producing a

pseudo-bidirectional terminal.

An external PHY can weakly drive the DUPLEX line high, indicating an intention for duplex operation. the

TNETX3150/TNETX3150A can override this DUPLEX terminal input by pulling the line low. This is detected by

the PHY, which monitors the sense of the DUPLEX signal, causing it to operate in half-duplex mode. Thus, the

TNETX3150/TNETX3150A can force the PHY into half-duplex operation when desired (during testing for

example). See Figure 3.

PHY

Resistor

Duplex Signal

Weakly Driven

Duplex Signal

Sense Feedback

TNETX3150/TNETX3150A

Duplex

Forced HD

GND

Active

Pulldown

Input

Signal

MXXDUPLEX

Figure 3. MXXDUPLEX Signal Connection

If the PHY is driven only in half-duplex operation, a pulldown resistor should be permanently attached to the

DUPLEX signal.

If the PHY is operated in full duplex (with the option of the TNETX3150/TNETX3150A forcing half duplex), a

pullup resistor should be placed on the DUPLEX signal.

TNETX3150A Datasheet(PDF) 20 Page - Texas Instruments

TNETX3150A Datasheet(HTML) 20 Page - Texas Instruments

Html Pages

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 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL