TriMatrix Memory
When the M512 RAM block is configured as a shift register block, a shift
register of size up to 576 bits is possible.
The M512 RAM block can also be configured to support serializer and
deserializer applications. By using the mixed-width support in
combination with DDR I/O standards, the block can function as a
SERDES to support low-speed serial I/O standards using global or
regional clocks. See “I/O Structure” on page 4–96 for details on dedicated
SERDES in Stratix GX devices.
M512 RAM blocks can have different clocks on its inputs and outputs.
The wren, datain, and write address registers are all clocked together
from one of the two clocks feeding the block. The read address, rden, and
output registers can be clocked by either of the two clocks driving the
block. This allows the RAM block to operate in read/write or
input/output clock modes. Only the output register can be bypassed. The
eight labclksignals or local interconnect can drive the inclock,
outclock, wren, rden, inclr, and outclrsignals. Because of the
advanced interconnect between the LAB and M512 RAM blocks, LEs can
also control the wrenand rdensignals and the RAM clock, clock enable,
and asynchronous clear signals. Figure 4–14 shows the M512 RAM block
control signal generation logic.
The RAM blocks within Stratix GX devices have local interconnects to
allow LEs and interconnects to drive into RAM blocks. The M512 RAM
block local interconnect is driven by the R4, R8, C4, C8, and direct link
interconnects from adjacent LABs. The M512 RAM blocks can
communicate with LABs on either the left or right side through these row
interconnects or with LAB columns on the left or right side with the
column interconnects. Up to 10 direct link input connections to the M512
RAM block are possible from the left adjacent LABs and another
10 possible from the right adjacent LAB. M512 RAM outputs can also
connect to left and right LABs through 10 direct link interconnects. The
M512 RAM block has equal opportunity for access and performance to
and from LABs on either its left or right side. Figure 4–15 shows the M512
RAM block to logic array interface.
4–24
Stratix GX Device Handbook, Volume 1
Altera Corporation
February 2005
ALTERA [ ALTERA CORPORATION ]
