188.8.131.52. Mixed-Port Read-During-Write Mode
The mixed-port read-during-write mode applies to simple and true dual-port RAM modes where two ports perform read and write operations on the same memory address using the same clock—one port reading from the address, and the other port writing to it.
|Output Mode||Memory Type||Description|
A read-during-write operation to different ports causes the MLAB registered output to reflect the “new data” on the next rising edge after the data is written to the MLAB memory.
This mode is available only if the output is registered.
|"old data"||M20K, MLAB||
A read-during-write operation to different ports causes the RAM output to reflect the “old data” value at the particular address.
For MLAB, this mode is available only if the output is registered.
|"don't care"||M20K, MLAB||
The RAM outputs “don’t care” or “unknown” value.
|"constrained don't care"||MLAB||
The RAM outputs “don’t care” or “unknown” value. The Quartus® Prime Pro Edition software analyzes the timing between write and read operations in the MLAB.
In the dual-port RAM mode, the mixed-port read-during-write operation is supported if the input registers have the same clock.
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