M7010R datasheet(46/67 Pages) STMICROELECTRONICS

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M7010R

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Mixed-sized Searches on Tables Configured with Different Width Using an M7010R Device

This subsection will cover mixed searches (x68,

x136, and x272) with tables of different widths

(x68, x136, and x272). The sample operation

shown is for a single device with CFG = 10010000,

containing three tables of x68, x136, and x272

widths. The operation can be generalized to a

block of 8 to 31 devices using four blocks; the tim-

ing and the pipeline operation is the same as de-

scribed previously for fixed searches on a table of

one-width-size.

Figure 34, page 47 shows three sequential

searches; first, a 68-bit SEARCH on a table con-

figured as x68, then a 136-bit SEARCH on a table

configured as x136, and finally a 272-bit SEARCH

on the table configured as x272. Each results in a

hit.

Note: The DQ[67:66] will be “00” in each of the two

A and B Cycles of the x68-bit SEARCH (Search1).

DQ[67:66] is “01” in each of the A and B Cycles of

the x136-bit SEARCH (Search2). DQ[67:66] is

“10” in each of the A, B, C, and D Cycles of the

x272-bit SEARCH (Search3). By having table des-

ignation bits, the M7010R device enables the cre-

ation of many tables of different widths in a bank of

search engines.

Figure 33 shows the sample table. Two bits in

each 68-bit entry need to be designated as table

number bits. One example choice might be: the

“00” values for the table configured as x68, “01”

values for tables configured as x136, and “10” val-

ues for tables configured as x272. For the above

explanation, it is further assumed that bits for

DQ[67:66] for each entry will be designed as such

table designation bits.

Figure 33. Multiwidth Configuration Example

CFG = 10010000

272

136

AI07046

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