Reset type

Reset logic for registers in HDL code

Model Configuration Pane: HDL Code Generation / Global Settings

Description

The Reset type parameter specifies whether to use asynchronous or synchronous reset logic when generating HDL code for registers.

Settings

Asynchronous (default) | Synchronous
Asynchronous

Uses asynchronous reset logic. The reset logic samples the reset independently of the clock signal.

For example, this process block, generated by a Unit Delay block, uses asynchronous resets. When the reset signal asserts, the process block performs a reset without checking for a clock event.

Unit_Delay1_process : PROCESS (clk, reset)
  BEGIN
    IF reset = '1' THEN
      Unit_Delay1_out1 <= (OTHERS => '0');
    ELSIF clk'event AND clk = '1' THEN
      IF clk_enable = '1' THEN
        Unit_Delay1_out1 <= signed(x_in);
      END IF;
    END IF; 
  END PROCESS Unit_Delay1_process;

Synchronous

Uses synchronous reset logic. The reset logic samples the reset with respect to the clock signal.

For example, this process block, generated by a Unit Delay block, checks for the rising edge before performing a reset:

Unit_Delay1_process : PROCESS (clk)
  BEGIN
    IF rising_edge(clk) THEN
      IF reset = '1' THEN
        Unit_Delay1_out1 <= (OTHERS => '0');
      ELSIF clk_enable = '1' THEN
        Unit_Delay1_out1 <= signed(x_in);
      END IF;
    END IF; 
  END PROCESS Unit_Delay1_process;

Tips

To set this property, use the functions hdlset_param or makehdl. To view the property value, use the function hdlget_param.

For example, to set this property for a subsystem named symmetric_fir in a model named sfir_fixed, use one of these methods:

  • Pass the property as an argument to the makehdl function.

    makehdl("sfir_fixed/symmetric_fir", ... 
        "ResetType","async")

  • Use hdlset_param to set the parameter on the model and then generate HDL code using makehdl.

    hdlset_param("sfir_fixed","ResetType","async")
makehdl("sfir_fixed/symmetric_fir")

Programmatic Use

Parameter: ResetType
Type: character vector
Value: "async" | "sync"
Default: "async"

Version History

Introduced in R2012a

See Also

Functions