ACEX1 datasheet(9/86 Pages) ETC

9 / 86 page

Altera Corporation

ACEX 1K Programmable Logic Device Family Data Sheet

Embedded Array Block

The EAB is a flexible block of RAM, with registers on the input and output

ports, that is used to implement common gate array megafunctions.

Because it is large and flexible, the EAB is suitable for functions such as

multipliers, vector scalars, and error correction circuits. These functions

can be combined in applications such as digital filters and

microcontrollers.

Logic functions are implemented by programming the EAB with a read-

only pattern during configuration, thereby creating a large LUT. With

LUTs, combinatorial functions are implemented by looking up the results

rather than by computing them. This implementation of combinatorial

functions can be faster than using algorithms implemented in general

logic, a performance advantage that is further enhanced by the fast access

times of EABs. The large capacity of EABs enables designers to implement

complex functions in a single logic level without the routing delays

associated with linked LEs or field-programmable gate array (FPGA)

RAM blocks. For example, a single EAB can implement any function with

8 inputs and 16 outputs. Parameterized functions, such as LPM functions,

can take advantage of the EAB automatically.

The ACEX 1K enhanced EAB supports dual-port RAM. The dual-port

structure is ideal for FIFO buffers with one or two clocks. The ACEX 1K

EAB can also support up to 16-bit-wide RAM blocks. The ACEX 1K EAB

can act in dual-port or single-port mode. When in dual-port mode,

separate clocks may be used for EAB read and write sections, allowing the

EAB to be written and read at different rates. It also has separate

synchronous clock enable signals for the EAB read and write sections,

which allow independent control of these sections.

The EAB can also be used for bidirectional, dual-port memory

applications where two ports read or write simultaneously. To implement

this type of dual-port memory, two EABs are used to support two

simultaneous reads or writes.

Alternatively, one clock and clock enable can be used to control the input

registers of the EAB, while a different clock and clock enable control the

output registers (see Figure 2).

ACEX1 Fiches technique(PDF) 9 Page - List of Unclassifed Manufacturers