Is the ramstyle synthesis attribute supported for VHDL memory inference when the memory is implemented using an array of natural types?

Description

Due to a problem in the Quartus® II software versions 13.0 SP1 and earlier, the ramstyle attribute is not supported when inferring memories in VHDL if the memory is implemented using an array of natural types.

Resolution

If you require the ramstyle attribute, use an array of std_logic_vector rather than natural types.

This problem is scheduled to be fixed in a future release of the Quartus II software.