etisserant@0: (* Following taken directly from the IEC 61131.3 draft standard *)
etisserant@0: 
etisserant@0: (*
etisserant@0:  * An IEC 61131-3 IL and ST compiler.
etisserant@0:  *
etisserant@0:  * Based on the
etisserant@0:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
etisserant@0:  *
etisserant@0:  *)
etisserant@0: 
etisserant@0: 
etisserant@0: (*
etisserant@0:  * This is part of the library conatining the functions
etisserant@0:  * and function blocks defined in the standard.
etisserant@0:  *
etisserant@0:  * Edge detection function blocks
etisserant@0:  * ------------------------------
etisserant@0:  *)
etisserant@0: 
etisserant@0: FUNCTION_BLOCK R_TRIG
etisserant@0:      VAR_INPUT  CLK: BOOL; END_VAR
etisserant@0:      VAR_OUTPUT  Q: BOOL; END_VAR
etisserant@0:      VAR RETAIN M: BOOL; END_VAR
etisserant@0: Q := CLK AND NOT M;
etisserant@0: M := CLK;
etisserant@0: END_FUNCTION_BLOCK
etisserant@0: 
etisserant@0: FUNCTION_BLOCK F_TRIG
etisserant@0:      VAR_INPUT  CLK: BOOL; END_VAR
etisserant@0:      VAR_OUTPUT   Q: BOOL; END_VAR
etisserant@0:      VAR RETAIN M: BOOL; END_VAR
etisserant@0: Q := NOT CLK AND NOT M;
etisserant@0: M := NOT CLK;
etisserant@0: END_FUNCTION_BLOCK
etisserant@0: