Reset Synchronization

Synchronization Circuit

Synchronization Code

Note that the three line comment below is a synthesis "pragma" for Synopsis Design Compiler and should be included verbatim in your code in order to prevent the tools from trying to add these flip-flops into the scan path.

// synopsys dc_tcl_script_begin
//   set_dont_touch [get_cells RESET_SYNC_FF*]
// synopsys dc_tcl_script_end

DFC1 RESET_SYNC_FF1 (
  .D('1),              .Q(SYNC_MID_nReset), .C(CORE_Clock), .RN(SYNC_IN_nReset)
);

DFC1 RESET_SYNC_FF2 (
   .D(SYNC_MID_nReset), .Q(CORE_nReset),    .C(CORE_Clock), .RN(SYNC_IN_nReset)
);

Which Reset Signal?

• The SYNC_IN_nReset signal in the figure above should come directly from the input pad driver cell and should connect only to these two flip-flops.

• The CORE_nReset signal in the figure above provides the global reset signal to the rest of the chip. If you have input synchronization flip-flops in your wrapper module these will use this global reset signal.