AR# 3733: M1.4 CPLD Hitop - Optimization disregards that control signals can have only 1 pterm.
M1.4 CPLD Hitop - Optimization disregards that control signals can have only 1 pterm.
Keywords: 1.4, cpld, hitop
The M1.4 software collapses logic into control signals disregarding that a control signal can have only 1 product term. Additional internal nodes are created to implement the collapsed logic. Each internal node occupies a macrocell and for this design we run out of resources and can't fit the design to the targeted device.
This problem is fixed in the latest M1.4 CPLD Patch available on the Xilinx support website: