SBPH400-3 Просмотр технического описания (PDF) - STMicroelectronics

Номер в каталоге

Компоненты Описание

Список матч

SBPH400-3

IEEE1394 3-Port 400Mbps Physical Layer

STMicroelectronics 

SBPH400-3

1 Overview

The SBPH 4 0 0-3 provides the analog transceiver functions needed to implement a 3 port

node in an IEEE 1394-1995 cable network. There are 2 differential line transceivers in each

cable port. The following main functions are included in the chip:

• Detection of connection status using line condition detection circuitry.

• Node initialization and bus arbitration.

• Reception and Transmission of Data Strobe Bit Level encoded packets

• Interface to higher level protocol devices (Link layer).

• Production test through JTAG

The interface to the Link conforms to the IEEE 1394-1995 Annex J with 2 control lines and an

8 bit data bus, as modified by the P1394a proposals.

The basic chip timing may be controlled either from a 24.596 MHz crystal controlling an

internal oscillator or from an external 24.596 MHz oscillator. The internal delay lock loop (DLL)

generates the various internal clocks for the high speed serial data transmission and

reception. Note that there is no need to provide filtering capacitors. The input clock is used to

derive the 49.152 MHz clock for the interface to a Link layer device, which provides the data

to be transmitted on the 8 bit Link data interface. The data from the Link layer device is latched

internally in the chip at 49.152 MHz. The bits are serialized and encoded in the Data Strobe

Bit Level Encoding format. The Data information is transmitted differentially on the TPB cable

pair(s) while the Strobe information is transmitted differentially on the TPA cable pair(s). Data

can be transmitted at 98.304 Mbit/s (S100 speed), 196.608 Mbit/s (S200 speed) or 393.216

Mbit/sec (S400 speed). When a packet is received by a port, the corresponding transmitters

are disabled and the receivers enabled. The received encoded Data information from TPA

cable pair and the encoded Strobe information from the TPB cable pair are decoded to extract

the receive clock signal and the data bits. The data bits are converted into a parallel format

and transmitted to the Link Layer controller and the other active cable ports after

resynchronisation to the system clock.

Figure 1.1 is a block diagram of the SBPH400-3. The portion of circuit which is circled by the

dash line is termed the Cable Media Interface. All signals between the Digital Circuit and the

Cable Media Interface are pure digital signals. The signals which are driven on and received

from the cable are analog differential and common mode signals. The differential signals on

the cable transmit data or arbitration states, while common mode signals indicate the cable

connection status or transmission rate (speed).

4/43

2

Share Link: