8

IDT77V106L25

PHY-ATM INTERFACE

UTOPIA Level 1 is a Physical (PHY) Layer to ATM Layer interface standardized by the ATM Forum. It is used for transferring ATM cells and has separate

transmit and receive channels and specific handshaking protocols. It is defined in ATM Forum documents af-phy-0017 and af-phy-0039.

There is a single 8-bit data bus in the transmit (ATM-to-PHY) direction, and a single 8-bit data bus in the receive (PHY-to-ATM) direction. In addition to

the data bus, each direction also includes a single optional parity bit and several handshaking signals. Please note that the transmit bus and the receive bus

operate completely independently.

4

PHY-ATM

Interface

Control -

RECV

4

5

NRZI

Decoding

RX +

RX

4

4

PRNG

Scramble

Nibble

Next

Reset

RXRef

32.0MHz

Clock

Synthesizer

&PLL

5b/4b

Decoding

Command

Byte

Detection,

Removal,

&Decode

De-

Scrambler

3505 drw 06

OSC

3 Cells

StartofCell

UTOPIA

Interface

.

The Utopia signals are summarized below:

TXDATA[7:0]

ATM to PHY

TXPARITY

ATM to PHY

TXSOC

ATM to PHY

TXEN

ATM to PHY

TXCLAV

PHY to ATM

TXCLK

ATM to PHY

RXDATA[7:0]

PHY to ATM

RXPARITY

PHY to ATM

RXSOC

PHY to ATM

RXEN

ATM to PHY

RXCLAV

PHY to ATM

RXCLK

ATM to PHY

Transmit and receive both utilize free running clocks, which are inputs to the 77V106. All utopia signals are timed to these clocks.

Figure 3. Receive Block Diagram