10.4.10.1.2 Cascading Blocks

Blocks can be cascaded to create larger sizes. The software performs all the necessary cascading for achieving the desired configuration. To achieve good performance, all cascaded RAM blocks must fit within one RAM column of the selected device. Cascading RAM blocks deep is possible only up to the capacity of one RAM column.

However, if the specified configuration exceeds one RAM column, the core configurator software tries to cascade the RAM wide, up to the available RAM Blocks in the device. This results in poorer performance as the RAM blocks are not physically close to one another.

The maximum WIDTH (word length) value is 65,536. The maximum DEPTH (number of words) value is 576. The Read/Write Width/Depth can be different but the aspect ratio should be same for both. For example:

Read Width * Read Depth == Write Width * Write Depth

The write enable (WE) and read enable (RE) signals are active high or low request signals for writing and reading, respectively; you may choose not to use them. When none is selected for an enable, that operation remains enabled all the time.

For example, if WEN is chosen as none, then write operation of the RAM is enabled all the time. The RCLK and WCLK pins have independent polarity selection.