3.5.6. Systolic Registers
There are two systolic registers per variable precision DSP block. If the variable precision DSP block is not configured in systolic FIR mode, both systolic registers are bypassed.
The first systolic register has two 18-bit registers that are used to register the upper multiplier’s two 18-bit inputs. You must clock these registers with the same clock source as the output register bank.
The second set of systolic registers are used to delay the chainout output to the next variable precision DSP block.