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2006 QuickLogic Corporation
Eclipse-E Family Data Sheet Rev. A
4
RAM Modules
The Eclipse-E family includes up to 24 dual-port 2,304-bit RAM modules for implementing RAM, ROM, and
FIFO functions. Each module is user-configurable into four different block organizations and can be cascaded
horizontally to increase their effective width, or vertically to increase their effective depth as shown in Figure 4.
Figure 3: 2,304-bit RAM Module
Using the two “mode” pins, designers can configure each module into 128 x 18 and 256 x 9. The blocks are
also easily cascadable to increase their effective width and/or depth (see Figure 4 Figure 4: Cascaded RAM Modules
The RAM modules are dual-port, with completely independent READ and WRITE ports and separate READ
and WRITE clocks. The READ ports support asynchronous and synchronous operation, while the WRITE
ports support synchronous operation. Each port has 18 data lines and 8 address lines, allowing word lengths
of up to 18 bits and address spaces of up to 256 words. Depending on the mode selected, however, some
higher order data or address lines may not be used.
The Write Enable (WE) line acts as a clock enable for synchronous write operation. The Read Enable (RE) acts
as a clock enable for synchronous READ operation (ASYNCRD input low), or as a flow-through enable for
asynchronous READ operation (ASYNCRD input high).
Designers can cascade multiple RAM modules to increase the depth or width allowed in single modules by
connecting corresponding address lines together and dividing the words between modules.
A similar technique can be used to create depths greater than 256 words. In this case address signals higher
than the MSB are encoded onto the write enable (WE) input for WRITE operations. The READ data outputs
are multiplexed together using encoded higher READ address bits for the multiplexer SELECT signals.
The RAM blocks can be loaded with data generated internally (typically for RAM or FIFO functions) or with
data from an external PROM (typically for ROM functions).
MODE[1:0]
WA[9:0]
WD[17:0]
WE
WCLK
ASYNCRD
RA[9:0]
RD[17:0]
RE
RCLK
WDATA
RDATA
WADDR
WDATA
RADDR
RAM
Module
(2,304 bits)
RAM
Module
(2,304 bits)