PWM Control

PoKeys devices feature a built-in PWM module operating at 25MHz clock frequency, providing high-precision timing control for servo motors, LED dimming, and motor speed control.

All PWM timing values must be expressed as clock cycles at 25MHz frequency:

use pokeys_lib::*;

fn main() -> Result<()> {
    let mut device = connect_to_device(0)?;
    
    // Configure PWM with 25MHz clock cycles
    // 20ms period = 0.020 × 25,000,000 = 500,000 cycles
    device.set_pwm_period(500000)?;
    
    // Enable PWM on pin 22 (PWM1)
    device.enable_pwm_for_pin(22, true)?;
    
    // Set duty cycle (1.5ms = 37,500 cycles for servo center)
    device.set_pwm_duty_cycle_for_pin(22, 37500)?;
    
    println!("PWM active on pin 22");
    
    // Disable PWM
    device.enable_pwm_for_pin(22, false)?;
    
    Ok(())
}

Complete servo positioning example with calibrated positions:

use pokeys_lib::*;
use std::thread;
use std::time::Duration;

fn main() -> Result<()> {
    let mut device = connect_to_device(0)?;
    
    // Configure for servo control (20ms period)
    device.set_pwm_period(500000)?;
    device.enable_pwm_for_pin(22, true)?;
    
    // Servo positions (calibrated for specific servo)
    let positions = [
        (60000, "0°"),   // Custom calibrated 0° position
        (36000, "90°"),  // Custom calibrated 90° position  
        (12000, "180°"), // Custom calibrated 180° position
    ];
    
    for (duty_cycles, angle) in positions.iter() {
        println!(\"Moving to {}\", angle);
        device.set_pwm_duty_cycle_for_pin(22, *duty_cycles)?;
        thread::sleep(Duration::from_secs(1));
    }
    
    // Return to center and disable
    device.set_pwm_duty_cycle_for_pin(22, 36000)?;
    thread::sleep(Duration::from_millis(500));
    device.enable_pwm_for_pin(22, false)?;
    
    Ok(())
}

High-level servo control with different servo types:

use pokeys_lib::*;

fn main() -> Result<()> {
    let mut device = connect_to_device(0)?;
    
    // 180-degree position servo
    let servo_180 = ServoConfig::one_eighty(22, 60000, 12000);
    device.configure_servo(servo_180.clone())?;
    device.set_servo_angle(&servo_180, 90.0)?; // Move to 90°
    
    // 360-degree position servo (multi-turn)
    let servo_360_pos = ServoConfig::three_sixty_position(20, 25000, 50000);
    device.configure_servo(servo_360_pos.clone())?;
    device.set_servo_angle(&servo_360_pos, 270.0)?; // Move to 270°
    
    // 360-degree speed servo (continuous rotation)
    // Datasheet: Counterclockwise 1-1.5ms, Stop 1.5ms, Clockwise 1.5-2ms
    let servo_speed = ServoConfig::three_sixty_speed(21, 37500, 50000, 25000);
    device.configure_servo(servo_speed.clone())?;
    device.set_servo_speed(&servo_speed, 50.0)?; // 50% clockwise
    device.stop_servo(&servo_speed)?; // Stop rotation
    
    Ok(())
}

For easier control, use percentage-based duty cycle functions:

use pokeys_lib::*;

fn main() -> Result<()> {
    let mut device = connect_to_device(0)?;
    
    // Set up PWM
    device.set_pwm_period(25000)?; // 1kHz for LED dimming
    device.enable_pwm_for_pin(22, true)?;
    
    // Fade LED from 0% to 100%
    for brightness in (0..=100).step_by(10) {
        device.set_pwm_duty_cycle_percent_for_pin(22, brightness as f32)?;
        println!(\"Brightness: {}%\", brightness);
        std::thread::sleep(std::time::Duration::from_millis(200));
    }
    
    // Turn off
    device.enable_pwm_for_pin(22, false)?;
    
    Ok(())
}

Control multiple PWM channels simultaneously:

use pokeys_lib::*;

fn main() -> Result<()> {
    let mut device = connect_to_device(0)?;
    
    // Configure PWM period (shared by all channels)
    device.set_pwm_period(500000)?; // 20ms for servo control
    
    // Enable multiple PWM channels
    let servo_pins = [22, 21, 20]; // PWM1, PWM2, PWM3
    for pin in servo_pins.iter() {
        device.enable_pwm_for_pin(*pin, true)?;
    }
    
    // Set different positions for each servo
    device.set_pwm_duty_cycle_for_pin(22, 60000)?; // Servo 1 to 0°
    device.set_pwm_duty_cycle_for_pin(21, 36000)?; // Servo 2 to 90°
    device.set_pwm_duty_cycle_for_pin(20, 12000)?; // Servo 3 to 180°
    
    println!("All servos positioned");
    
    // Disable all channels
    for pin in servo_pins.iter() {
        device.enable_pwm_for_pin(*pin, false)?;
    }
    
    Ok(())
}