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MTC20455

Utopia Level 2 Signals

The physical layer chip sends cell data towards the ATM layer chip. The ATM layer chip polls the status

of the FIFO of the physical layer chip. Refer to Table 6 for a list of interface signals. The cell exchange

proceeds like:

a) The physical layer chip signals the availability of a cell by asserting RxClav when polled by the ATM

chip.

b) The ATM chips selects a physical layer chip, then starts the transfer by asserting notRxEnb.

c) If the physical layer chip has data to send, it puts them on the RxData line the cycle after it sampled

notRxEnb active. It also advances the offset in the cell. If the data transferred is the first byte of a cell,

RxSOC is 1b at the time of the data transfer, 0b otherwise.

d) The ATM chip accepts the data when they are available. If RxSOC was 1b during the transfer, it resets

its internal offset pointer to the value 1, otherwise it advances the offset in the cell.

MTC20455 Utopia Level 2 MPHY Operation

Utopia level 2 MPHY operation can be done by various interface schemes. The MTC20455 supports only

the required mode, this mode is referred to as «operation with 1 TxClav and 1 RxClav.»

PHY Device Identification

The MTC20455 holds 2 PHY layer Utopia ports, one is dedicated to the fast data channel, the other one

to the interleaved data channel. The associated PHY address is specified by the PHY_ADDR_x fields the

Utopia PHY address register. Beware that an incorrect address configuration may lead to bus conflicts.

MTC20136 Transceiver Controller Interface

Table 18. All signals

Figure 12. PCLK Clock frequency

Table 19. Address with respect to ALE

Symbol

Parameter

Min

Typ

Max

Unit

tr, tf

Rise and Fall time (10% - 90%)

3

ns

Ci

Input load

10

pF

Co

Output load

20

pF

Symbol

Parameter

Min

Typ

Max

Unit

f

PCLK clock frequency

8

33

MHz

Symbol

Parameter

Min

Typ

Max

Unit

tr,tf

Rise and Fall time (10% - 90%)

4

ns

Talew

ALE pulse width

12

ns

Tavs

Address valid setup time

7

ns

Tavh

Address valid hold time

8

ns