Struct FTrig 

pub struct FTrig {
    pub clk: bool,
    pub q: bool,
    /* private fields */
}

Falling Edge Trigger (F_TRIG)

Detects a falling edge (true → false transition) on the input signal. The output q is true for exactly one cycle when the input clk transitions from true to false.

This is equivalent to the IEC 61131-3 F_TRIG function block.

Example

use autocore_std::fb::FTrig;

let mut trigger = FTrig::new();

// Signal starts low
assert_eq!(trigger.call(false), false);

// Signal goes high
assert_eq!(trigger.call(true), false);

// Falling edge detected!
assert_eq!(trigger.call(false), true);

// Signal still low, edge already passed
assert_eq!(trigger.call(false), false);

Timing Diagram

clk: _____|‾‾‾‾‾‾‾‾‾|_____|‾‾‾‾‾
  q: _______________|‾|________

Use Cases

• Detecting button releases
• Detecting signal loss
• Triggering actions when a condition ends

Fields

clk: bool

Current input value

q: bool

Output: true for one cycle on falling edge

Implementations

impl FTrig

pub fn new() -> Self

Creates a new falling edge trigger with all values initialized to false.

Example

use autocore_std::fb::FTrig;

let trigger = FTrig::new();
assert_eq!(trigger.q, false);

pub fn call(&mut self, clk: bool) -> bool

Executes the falling edge detection logic.

Call this method once per control cycle with the current input value. Returns true for exactly one cycle when a falling edge is detected.

Arguments

• clk - The current state of the input signal

Returns

true if a falling edge (true → false transition) was detected, false otherwise.

Example

use autocore_std::fb::FTrig;

let mut trigger = FTrig::new();

// Simulate button release
trigger.call(true);  // Button held
if trigger.call(false) {  // Button released
    println!("Button was just released!");
}

Trait Implementations

impl Clone for FTrig

fn clone(&self) -> FTrig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FTrig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FTrig

fn default() -> Self

Returns the “default value” for a type.