Timing driven clock tree synthesis
This application discloses performing a static timing analysis on a circuit design with an unbalanced clock tree, for example, to determine data arrival timing and clock arrival timing at multiple clock-driven circuits in a circuit design, and then performing clock tree synthesis on the circuit design to initially balance the unbalanced clock tree based, at least in part, on the data arrival timing relative to the clock arrival timing at the multiple clock-driven circuits. The clock tree after initial balancing includes a clock signal path configured to provide a clock signal to each of the multiple clock-driven circuits with a new clock arrival timing that corresponds to the data arrival timing.
1. A method comprising:
determining, by a computing system, data arrival timing and clock arrival timing at multiple clock-driven circuits in a circuit design describing at least a portion of an electronic device; and
performing, by the computing system, clock tree synthesis (CTS) on the circuit design, which synthesizes an unbalanced clock tree for the circuit design and utilizes the data arrival timing relative to the clock arrival timing at the multiple clock-driven circuits to initially balance the unbalanced clock tree for the circuit design, wherein the initial balancing of the unbalanced clock tree alters a clock signal path in the unbalanced clock tree to provide a clock signal to each of the multiple clock-driven circuits with a new clock arrival timing that is synchronized with the data arrival timing for the multiple clock-driven circuits, and wherein the electronic device is capable of being manufactured based, at least in part, on the circuit design.
2. The method of claim 1 , wherein performing clock tree synthesis (CTS) for the circuit design further comprising:
establishing, by the computing system, multiple branches for the clock signal path to couple a clock source device in the circuit design to each of the multiple clock-driven circuits; and
inserting, by the computing system, buffers into the clock signal path to selectively delay the clock signal through different branches of the clock signal path.
3. The method of claim 1 , wherein performing clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design is based, at least in part, on a total negative slack (TNS).
4. The method of claim 1 , wherein performing clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design is based, at least in part, on a total hold slack (THS).
5. The method of claim 1 , wherein determining the data arrival timing at multiple clock-driven circuits further comprising:
performing, by the computing system, static timing analysis (STA) on the circuit design having an unbalanced clock tree; and
determining, by the computing system, propagation delays in data paths between the multiple clock-driven circuits based on the static timing analysis, wherein the data arrival timing at the multiple clock-driven circuits is based, at least in part, on the propagation delays in the data paths between the multiple clock-driven circuits.
6. The method of claim 1 , wherein performing clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design is independent of skew resulting from non-synchronous arrival times for the clock signals at the multiple clock-driven circuits.
7. A system comprising:
a static timing analysis tool configured to determine data arrival timing and clock arrival timing at multiple clock-driven circuits in a circuit design describing at least a portion of an electronic device; and
a clock tree synthesis unit configured to perform clock tree synthesis (CTS) on the circuit design, which synthesizes an unbalanced clock tree for the circuit design and utilizes the data arrival timing relative to the clock arrival timing at the multiple clock-driven circuits to initially balance an unbalanced clock tree for the circuit design, wherein the initial balancing of the unbalanced clock tree alters a clock signal path in the unbalanced clock tree to provide a clock signal to each of the multiple clock-driven circuits with a new clock arrival timing that is synchronized with the data arrival timing for the multiple clock-driven circuits, and wherein the electronic device is capable of being manufactured based, at least in part, on the circuit design.
8. The system of claim 7 , wherein the clock tree synthesis unit is configured to establish multiple branches for the clock signal path to couple a clock source device in the circuit design to each of the multiple clock-driven circuits, and insert buffers into the clock signal path to selectively delay the clock signal through different branches of the clock signal path.
9. The system of claim 7 , wherein the clock tree synthesis unit is configured to perform the clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design based, at least in part, on a total negative slack (TNS).
10. The system of claim 7 , wherein the clock tree synthesis unit is configured to perform the clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design based, at least in part, on a total hold slack (THS).
11. The system of claim 7 , wherein static timing analysis tool is configured to perform static timing analysis (STA) on the circuit design having an unbalanced clock tree and determine propagation delays in data paths between the multiple clock-driven circuits based on the static timing analysis, and wherein the data arrival timing at the multiple clock-driven circuits is based, at least in part, on the propagation delays in the data paths between the multiple clock-driven circuits.
12. An apparatus comprising at least one computer-readable memory device storing instructions configured to cause one or more processing devices to perform operations comprising:
generating an unbalanced clock tree for a circuit design describing at least a portion of an electronic device; and
performing clock tree synthesis (CTS) on the circuit design, which synthesizes an unbalanced clock tree for the circuit design and utilizes data arrival timing relative to clock arrival timing at multiple clock-driven circuits in the circuit design having the unbalanced clock tree to initially balance the unbalanced clock tree for the circuit design, wherein the initial balancing of the unbalanced clock tree alters a clock signal path in the unbalanced clock tree to provide a clock signal to each of the multiple clock-driven circuits with a new clock arrival timing that is synchronized with the data arrival timing for the multiple clock-driven circuits, and wherein the electronic device is capable of being manufactured based, at least in part, on the circuit design.
13. The apparatus of claim 12 , wherein performing clock tree synthesis (CTS) for the circuit design further comprising:
establishing multiple branches for the clock signal path to couple a clock source device in the circuit design to each of the multiple clock-driven circuits; and
inserting buffers into the clock signal path to selectively delay the clock signal through different branches of the clock signal path.
14. The apparatus of claim 12 , wherein performing clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design is based, at least in part, on a total negative slack (TNS).
15. The apparatus of claim 12 , wherein performing clock tree synthesis (CTS) that initially balances the unbalanced clock tree for the circuit design is based, at least in part, on a total hold slack (THS).
16. The apparatus of claim 12 , wherein the instructions configured to cause one or more processing devices to perform operations further comprising performing static timing analysis (STA) on the circuit design having the unbalanced clock tree to determine the data arrival timing and the clock arrival timing at the multiple clock-driven circuits.
17. The apparatus of claim 12 , wherein performing clock tree synthesis (CTS) describing at least a portion of an electronic device for the circuit design is independent of skew resulting from non-synchronous arrival times for the clock signals at the multiple clock-driven circuits.