DLATCH

Block Screenshot

Contents

• D latch flip-flop

• • Palette

  • Description

  • Data types

  • Default properties

  • Interfacing function

  • Example

  • See also

Palette

• Integer palette

Description

This block copies its input state (D) on the output (Q) when the enable input (C) is high and in this configuration it appears as transparent. The !Q output is the logical negation of Q

When the enable input goes low, the output keeps its previous state and acts like a memory.

This block can be typically used in I/O ports.

The truth table of the block is the following ones:

				No changes
				Reset
				Set

where X means "indifferent" and Qn-1 the previous state of Qn .

Data types

The block supports the following types :

• Inputs:

  • D: scalar. Scilab's int8 data type only.

  • C: scalar. Scilab's real double.

  A positive input is considered as logical 1, a negative or a null input as logical 0.

• Ouputs: scalar. Scilab's int8 data type.

Default properties

• always active: no

• direct-feedthrough: yes

• zero-crossing: no

• mode: no

• regular inputs:

  - port 1 : size [1,1] / type 5

  - port 2 : size [1,1] / type -1

• regular outputs:

  - port 1 : size [1,1] / type 5

  - port 2 : size [1,1] / type 5

• number/sizes of activation inputs: 0

• number/sizes of activation outputs: 0

• continuous-time state: no

• discrete-time state: no

• object discrete-time state: no

• name of computational function: csuper

Example

The following figure shows a simple use case of the DLATCH block with its timing diagram.

Interfacing function

• SCI/modules/scicos_blocks/macros/IntegerOp/DLATCH.sci

See also

• DFLIPFLOP — D flip-flop
• SRFLIPFLOP — SR flip-flop
• JKFLIPFLOP — JK flip-flop