Stratix II Architecture
The M4K RAM blocks allow for different clocks on their inputs and
outputs. Either of the two clocks feeding the block can clock M4K RAM
block registers (renwe, address, byte enable, datain, and output registers).
Only the output register can be bypassed. The six labclksignals or local
interconnects can drive the control signals for the A and B ports of the
M4K RAM block. ALMs can also control the clock_a, clock_b,
renwe_a, renwe_b, clr_a, clr_b, clocken_a, and clocken_b
signals, as shown in Figure 2–21.
The R4, C4, and direct link interconnects from adjacent LABs drive the
M4K RAM block local interconnect. The M4K RAM blocks can
communicate with LABs on either the left or right side through these row
resources or with LAB columns on either the right or left with the column
resources. Up to 16 direct link input connections to the M4K RAM Block
are possible from the left adjacent LABs and another 16 possible from the
right adjacent LAB. M4K RAM block outputs can also connect to left and
right LABs through direct link interconnect. Figure 2–22 shows the M4K
RAM block to logic array interface.
Figure 2–21. M4K RAM Block Control Signals
Dedicated
Row LAB
Clocks
6
Local
Interconnect
Local
Interconnect
Local
Interconnect
Local
Interconnect
Local
Interconnect
Local
Interconnect
Local
Interconnect
clocken_b
clock_b
renwe_b
aclr_b
Local
Interconnect
renwe_a
aclr_a
clock_a
clocken_a
Altera Corporation
May 2007
2–33
Stratix II Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
