ProASICPLUS Flash Family FPGAs
v5.9
2-23
Note: Each RAM block contains a multiplexer (called DMUX) for each output signal, increasing design efficiency. These DMUX cells do not
consume any core logic tiles and connect directly to high-speed routing resources between the RAM blocks. They are used when
RAM blocks are cascaded and are automatically inserted by the software tools.
Figure 2-19 Basic FIFO Block Diagrams
Table 2-15 Memory Block FIFO Interface Signals
FIFO Signal
Bits
In/Out
Description
WCLKS
1
In
Write clock used for synchronization on write side
RCLKS
1
In
Read clock used for synchronization on read side
LEVEL <0:7>
8
In
Direct configuration implements static flag logic
RBLKB
1
In
Read block select (active Low)
RDB
1
In
Read pulse (active Low)
RESET
1
In
Reset for FIFO pointers (active Low)
WBLKB
1
In
Write block select (active Low)
DI<0:8>
9
In
Input data bits <0:8>, <8> will be generated parity if PARGEN is true
WRB
1
In
Write pulse (active Low)
FULL, EMPTY
2
Out
FIFO flags. FULL prevents write and EMPTY prevents read
EQTH, GEQTH
2
Out
EQTH is true when the FIFO holds the number of words specified by the LEVEL signal.
GEQTH is true when the FIFO holds (LEVEL) words or more
DO<0:8>
9
Out
Output data bits <0:8>. <8> will be parity output if PARGEN is true.
RPE
1
Out
Read parity error (active High)
WPE
1
Out
Write parity error (active High)
LGDEP <0:2>
3
In
Configures DEPTH of the FIFO to 2 (LGDEP+1)
PARODD
1
In
Parity generation/detect – Even when Low, odd when High
FIFO
(256x9)
LEVEL<0:7>
DO <0:8>
DI<0:8>
WRB
RDB
WBLKB
RBLKB
RPE
PARODD
WPE
LGDEP<0:2>
FULL
EMPTY
EQTH
GEQTH
WCLKS
RCLKS
RESET
RPE
WPE
FULL
EMPTY
EQTH
GEQTH
DO <0:8>
RPE
WPE
FULL
EMPTY
EQTH
GEQTH
DI <0:8>
DO <0:8>
LEVEL <0:7>
WRB
RDB
WBLKB
RBLKB
RPE
PARODD
WPE
LGDEP<0:2>
DI <0:8>
LEVEL <0:7>
WRB
RDB
WBLKB
RBLKB
PARODD
LGDEP<0:2>
FULL
EMPTY
EQTH
GEQTH
RCLKS
RESET
LEVEL<0:7>
DI<0:8>
WRB
RDB
WBLKB
RBLKB
PARODD
LGDEP<0:2>
WCLKS
DO <0:8>
FIFO
(256x9)
FIFO
(256x9)
FIFO
(256x9)
Sync Write
and
Sync Read
Ports
Sync Write
and
Async Read
Ports
Async Write
and
Sync Read
Ports
and
Async Read
Ports