const PWM = require("rpio-pwm");
let pwmCh, stepNum = 500, refresh = 50, pinBoardCode = 18

console.log("初始化 PWM 通道");
PWM.set_log_level(PWM.logLevel.debug);

const cycleTimeUs = (1000 / refresh) * 1000,
    stepTimeUs = cycleTimeUs / stepNum,
    steeringPWMCfg = {
        cycle_time_us: cycleTimeUs,
        step_time_us: stepTimeUs,
        delay_hw: 1,
    };

pwmCh = PWM.create_dma_channel(
    PWM.host_is_model_pi4() ? 5 : 12,
    steeringPWMCfg
);


const pin = pwmCh.create_pwm(pinBoardCode);

pin.set_width((256 / 100) * stepNum);

setTimeout(function () {
    // it's good idea to cleanup before exit.
    console.log('clear');
    pwmCh.shutdown();
}, 2000);