i2c - What am I doing wrong?

[jzellis]

I'm trying to create a driver for the Waveshare motor shield for Pico, which is based on the PCA9685 for PWM. Waveshare only ever gives out Python demo code rather than, y'know, useful documentation, so I've spent all day converting their MicroPython code into Kaluma code.

I've finally got it all outputting the correct stuff to the console, but it just doesn't do anything. It doesn't fail, emits no errors, just...nothing. If I reflash the board with the MicroPython interpreter and run their demo code, it works fine.

Does the i2c stuff work in Kaluma? If so, what could I be doing wrong? The MicroPython and Kaluma implementations of i2c have different parameters, so I'm not sure I'm doing this correctly.

My code:

const {
    I2C
} = require('i2c');
const {
    PWM
} = require('pwm');


class PCA9685 {
    constructor() {
        this.SCL = 21;
        this.SDA = 20;
        this.BAUDRATE = 100000;
        this.I2CADR = 0x40;
        this.SUBADR1 = 0x02;
        this.SUBADR2 = 0x03;
        this.SUBADR3 = 0x04;
        this.MODE1 = 0x00;
        this.PRESCALE = 0xFE;
        this.LED0_ON_L = 0x06;
        this.LED0_ON_H = 0x07;
        this.LED0_OFF_L = 0x08;
        this.LED0_OFF_H = 0x09;
        this.ALLLED_ON_L = 0xFA;
        this.ALLLED_ON_H = 0xFB;
        this.ALLLED_OFF_L = 0xFC;
        this.ALLLED_OFF_H = 0xFD;
        this.PWMFREQ = 50;

        let i2c = new I2C(0, {
            baudrate: 100000,
            scl: 21,
            sda: 20
        });

        this.i2c = i2c;

        const write = function (cmd, val) {
            try {
                // let valArray = new Uint8Array([parseInt(val)]);
                let valArray = parseInt(val).toString();

                let howMany = this.i2c.memWrite(valArray, this.I2CADR, cmd);
                console.log("I2C: Wrote " + howMany + " bytes: " + valArray.toString(16) + " to " + cmd + " on address " + this.I2CADR)
            } catch (e) {
                console.error(e)
            }
        }

        const read = function (reg) {
            try {

                let rdate = this.i2c.memRead(1, this.I2CADR, reg);
                if (typeof rdate != 'undefined')
                    return rdate[0]
            } catch (e) {
                console.error(e)
            }
        }


        this.write = write;
        this.read = read;

        const setPWM = function (channel, on, off) {
            console.log("Setting single PWM channel")
            this.write(this.LED0_ON_L + 4 * channel, on & 0xFF)
            this.write(this.LED0_ON_H + 4 * channel, on >> 8)
            this.write(this.LED0_OFF_L + 4 * channel, off & 0xFF)
            this.write(this.LED0_OFF_H + 4 * channel, off >> 8)
            console.log("channel " + channel + " LED_ON: " + on + " LED_OFF: " + off)
        }

        const setServoPulse = function (channel, pulse) {
            pulse = pulse * (4095 / 100);
            this.setPWM(channel, 0, parseInt(pulse));
        }

        const setLevel = function (channel, value) {
            if (value === 1) {
                this.setPWM(channel, 0, 4095)
            } else {
                this.setPWM(channel, 0, 0)
            }
        }

        this.setPWM = setPWM;
        this.setServoPulse = setServoPulse;
        this.setLevel = setLevel;


        function setPWMFreq(freq) {
            let prescaleval = 25000000.0 // 25MHz
            prescaleval /= 4096.0 // 12-bit
            prescaleval /= parseFloat(freq);
            prescaleval -= 1.0;
            let prescale = Math.floor(prescaleval + 0.5);
            let oldmode = this.read(this.MODE1);
            console.log("Oldmode: " + oldmode)
            let newmode = (oldmode & 0x7F) | 0x10;
            console.log("Newmode: " + newmode)

            this.write(this.MODE1, newmode);
            // prescale = Math.floor(prescale)
            this.write(this.PRESCALE, parseInt(prescale));

            this.write(this.MODE1, oldmode);
            delay(50)

            this.write(this.MODE1, oldmode | 0x80);
        }

        this.setPWMFreq = setPWMFreq;


    }

}

class MotorDriver {

    constructor() {
        let pwm = new PCA9685();
        pwm.setPWMFreq(50)
        this.pwm = pwm;
        this.MOTORS = {
            A: {
                on: 0,
                d1: 1,
                d2: 2
            },
            B: {
                on: 3,
                d1: 4,
                d2: 5
            },
            C: {
                on: 6,
                d1: 7,
                d2: 8
            },
            D: {
                on: 9,
                d1: 10,
                d2: 11
            }
        }


        const MotorOn = function (motor = "A", direction = "forward", speed) {
            // if (speed > 100) speed = 100;
            console.log("Motor is: " + JSON.stringify(this.MOTORS[motor]));
            console.log(`
            Turning on ${motor} to ${speed}`);
            this.pwm.setServoPulse(this.MOTORS[motor].on, speed);
            if (direction === "forward") {
                this.pwm.setLevel(this.MOTORS[motor].d1, 1);
                this.pwm.setLevel(this.MOTORS[motor].d1, 0);
            } else {
                this.pwm.setLevel(this.MOTORS[motor].d1, 0);
                this.pwm.setLevel(this.MOTORS[motor].d1, 1);
            }

        }

        const MotorOff = function (motor = "A") {
            console.log(`
            Turning off ${motor}`);
            this.pwm.setServoPulse(this.MOTORS[motor].on, 0);
            this.pwm.setLevel(this.MOTORS[motor].d1, 0);
            this.pwm.setLevel(this.MOTORS[motor].d1, 0);

        }

        this.MotorOn = MotorOn;
        this.MotorOff = MotorOff;


    }

}

const m = new MotorDriver();

m.MotorOn("A", "forward", 100)
delay(1000);
m.MotorOn("A", "forward", 50)
delay(1000)
m.MotorOff("A");

Everything looks right, nothing happens. What obvious stupid thing am I missing here?

If I can get this working I'll improve it a bit and publish it as an npm, because I think a lot of folks use these shields. I just need to get it working! 😭

[niklauslee]

It's so hard to reproduce the problem on my side. I'd appreciate it if you could simplify the code so that I can reproduce the I2C problem.