Carlos Dangelo

Specification, planning, and synthesis in a VHDL design environment

Silicon 1076, a very-high-speed integrated circuit hardware description language (VHDL) design environment developed for specifying, simulating, and synthesizing digital hardware, is described. The environment integrates software tools for architectural-level design space exploration and synthesis and RTL synthesis. Silicon 1076 supports a top-down design methodology, while making use of bottom-up design information such as area and delay of modules and interconnect and routing estimates. The flexible design environment allows the user to describe separate parts of the design at different abstraction levels and to perform mixed-level VHDL simulation and synthesis. With the synthesis tools, the user can perform high-level what-if analysis and planning by constraining and exploring portions of the design space.<<ETX>>

Timing estimation for behavioral descriptions

Behavioral or high-level synthesis (HLS) generally produces a register transfer level (RTL) code which in turn is synthesized into a netlist. The RTL code that is generated by the HLS program needs to meet user constraints such as clock cycle, available function units, area, etc. This paper shows that most synthesis programs will not meet the user timing constraint in many cases. As a result, a generated design might be functionally incorrect. We present an algorithm for estimating the minimum clock cycle for a synthesized design. The algorithm considers false paths, interconnect, wire and control unit delays to derive the minimal clock cycle time. A method that uses the algorithm to synthesize behavioral descriptions that meet the user timing constraints is also given.<<ETX>>