HL2.AUG–MUSIC Semiconductors, Inc.–RM
Content-addressable memory allows associated data caching on chip
Cascadable chips allow search of large data blocks and rapid retrieval of
linked items
The MU9C1640 is a 1-K x 64-bit content-addressable memory (CAM). The user
can configure each of its 64-bit lines into CAM and RAM on any 16-bit
boundary. When the CAM search turns up a hit address, either the address
or the associated data from the RAM partition may be returned to the
output (see diagram). The device is controlled by four external control
signals along with an instruction register. Two bits appended to each data
field indicate one of four validity conditions: valid, skip, empty, and
random-access only. Two mask registers can be programmed to mask compares
or data writes. If 1,024 locations are insufficient, the MU9C1640 can be
cascaded without external logic. After a search, the status register
contains the highest-priority match. External flags indicate match and
multiple match, and these signals cascade. A cascaded string of devices
correctly executes write to first empty address just like a single chip.
The internal data path is 64 bits wide, multiplexed to a 16-bit I/O port.
Multiplexing fits the device into a 44-pin package. Memory cycles can be
write-at-next-free-address, random access, or associative access. Access
grades are 40 and 55 ns. (44-pin PLCC, 55 ns, $25 ea/1,000–available now.
) MUSIC Semiconductors, Inc. Colorado Springs, CO Bruce Threewitt
719-570-1550 Fax 719-570-1555
CAPTION:
The 1-K x 64-bit array can be partitioned on 16-bit boundaries into
content-addressable and random-access partitions.
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