PM7344 datasheet(75/293 Pages) PMC

75 / 293 page

PM7344 S/UNI-MPH

DATA SHEET

PMC-950449

ISSUE 6

MULTI-PHY USER NETWORK INTERFACE

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

A Saturn Compatible Interface (SCI-PHYTM) FIFO is provided. This synchronous

FIFO accepts a read clock (RFCLK) and read enable signal from the MPHY

block. The receive FIFO output bus is tristated when the read enable is inactive.

The interface indicates the start of a cell (RSOC) and the receive cell available

status (RCA) when data is read from the receive FIFO (using the rising edges of

RFCLK while read enable is active). The RCA status changes from available to

unavailable when the FIFO is 4 byte read accesses away from being empty (or

when the FIFO is empty, when REMPTY4 is logic 0).

This RXFF indicates FIFO overruns using a maskable interrupt and register bits.

The FIFO is reset on FIFO overrun, causing up to 4 cells to be lost.

9.18

Transmit ATM Cell Processor (TXCP)

The Transmit Cell Processor (TXCP) Block integrates circuitry to support ATM

cell payload scrambling, header check sequence (HCS) generation, and

idle/unassigned cell generation.

The TXCP scrambles the cell payload field using the self synchronizing

scrambler with polynomial x43 + 1. The header portion of the cells is not

scrambled. Note that cell payload scrambling is optional in the S/UNI-MPH.

The HCS is generated using the polynomial, x8 + x2 + x + 1. The coset

polynomial x6 + x4 + x2 + 1 is added (modulo 2) to the calculated HCS octet as

required by the ATM Forum UNI specification, and ITU-T Recommendation I.432.

The resultant octet optionally overwrites the HCS octet in the transmit cell.

When the transmit FIFO is empty, the TXCP inserts idle/unassigned cells. The

idle/unassigned cell header is fully programmable using five internal registers.

Similarly, the 48 octet information field is programmed with an 8 bit repeating

pattern using an internal register. The TXCP accumulates the number of

transmitted assigned cells in a saturating counter.

For T1/E1 formats, the cell octets are byte aligned with the transmission

overhead (the framing bit for the T1 format, and timeslots 0/16 for the E1 format).

For arbitrary bit rate interfaces, the cell octets are optionally aligned to the

overhead indication signal (TOHI).

9.19

Transmit ATM 4 Cell FIFO (TXFF)

The Transmit FIFO (TXFF) provides FIFO management and the S/UNI-MPH

transmit cell interface. The transmit FIFO can hold up to four cells. The FIFO

depth may be programmed to one, two, three, or four cells. The FIFO provides

the cell rate decoupling function between the transmission system physical layer

and the ATM layer.

PM7344 датащи(PDF) 75 Page - PMC-Sierra, Inc

PM7344 датащи(HTML) 75 Page - PMC-Sierra, Inc

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

датащи скачать

ссылки URL