Altera Internal Memory (RAM and ROM) IP Core User Manual
Page 40
Parameter
Legal Values
Description
When you select With one read port and one write
port, the following option is available:
• How should the q output behave when reading a
memory location that is being written from the
other port?
When you select With two read /write ports, the
following option is available:
• How should the q_a and q_b outputs behave
when reading a memory location that is being
written from the other port?
•
Old memory
contents appear
•
I do not care
Specifies the output behavior
when read-during-write
occurs.
• Old memory contents
appear— The RAM
outputs reflect the old
data at that address before
the write operation
proceeds.
• I do not care—This
option functions
differently when you turn
it on depending on the
following memory block
type you select:
• When you set the
memory block type to
Auto, M144K, M512,
M4K, M9K, M10K,
M20K or any other
block RAM, the RAM
outputs ‘don't care’ or
“unknown” values for
read-during-write
operation without
analyzing the timing
path.
• When you set the
memory block type to
MLAB (for LUTRAM)
, the RAM outputs
‘dont care’ or
‘unknown’ values for
read-during-write
operation but analyzes
the timing path to
prevent metastability.
Do not analyze the timing between write and read
operation. Metastability issues are prevented by
never writing and reading at the same address at the
same time.
On/Off
Turn on this option when
you want the RAM to output
‘don’t care’ or unknown
values for read-during-write
operation without analyzing
the timing path. This option
is only available for
LUTRAM and is enabled
when you set memory block
type to MLAB.
Parameter Settings: Output 2 (This tab is only available when you select two read/ write ports)
UG-01068
2014.12.17
RAM: 2-Port IP Core Parameters
4-15
Embedded Memory Signals and Parameters
Altera Corporation