2.7. Force-to-Zero
For example, you multiplex two M20K blocks, each supporting a maximum of 2048 bits memory depth to create a RAM block with 4096 bits memory depth. By enabling the force-to-zero feature, you can replace the OR gate with multiplexing circuitry at the output of the M20K block when performing address width stitching.
Because the MSB of the address controls the read enable signal in the force-to-zero mode, the outputs of other memory blocks are forced to zero when the read enable signal deasserts. The data output being read out is from the output of the selected memory block only.
You can turn on the Enable Force-to-Zero feature option in the parameter editors of the RAM/ROM IPs. If you turn on this option, the read enable signal does not retain previous values when the signal deasserts.