Can't get motors to initialize, ledcWriteChannel() error

[sliwowitz]

I'm on ESP32, running Madflight v2.1.0. I'm compiling via PlatformIO (with pioarduino to get the latest Arduino framework for ESP). I'm trying to get a basic Quad running, but it doesn't recognize my motors.

I've tried to put some debug Serial prints to find where it gets stuck, and I think the

bool found = ledcAttachChannel(pin, freq, bits, ch);`

line in ESP32_PWM_v3.h never returns, and keeps spamming the serial console with errors:

PWM::begin(pin=33,freq=400,min_us=950.000000,max_us=2000.000000)
[191409][E][esp32-hal-ledc.c:205] ledcWriteChannel(): Channel 255 is not available (maximum 16) or not used!
[191419][E][esp32-hal-ledc.c:205] ledcWriteChannel(): Channel 255 is not available (maximum 16) or not used!
[191428][E][esp32-hal-ledc.c:205] ledcWriteChannel(): Channel 255 is not available (maximum 16) or not used!
[191438][E][esp32-hal-ledc.c:205] ledcWriteChannel(): Channel 255 is not available (maximum 16) or not used!
...

In the main file, I'm calling:

bool success = out.setupMotors(4, motor_idxs, motor_pins, 400, 950, 2000);

The pins are 33, 25, 26, 27.

The same error appears when trying to use OpenShot125 PWM::begin(pin=33,freq=2000,min_us=125.000000,max_us=250.000000), then the errors start printing endlessly.

[sliwowitz]

A test program wit OpenShot125 seems to run fine:

#include <Arduino.h>
#include <array>
#include "esp32-hal-ledc.h"
#include "led_blinker.h"

constexpr std::array<uint8_t,4>  esc_pins {33, 25, 26, 27}; // GPIO pins for ESCs
constexpr std::array<int,4>      esc_ch  {0, 1, 2, 3}; // LEDC channels for ESCs

constexpr uint8_t INTERNAL_LED_PIN = 2;                  // onboard LED

constexpr uint32_t ONESHOT_FREQ = 4000;                  // 250 µs period
constexpr uint8_t  PWM_BITS     = 10;                    // 0‑1023
constexpr uint16_t DUTY_MIN     = 512;                   // 125 µs
constexpr uint16_t DUTY_MAX     = 1023;                  // 250 µs

LedBlinker blinker(INTERNAL_LED_PIN);

void setup() {
    Serial.begin(115200);
    blinker.setup();

    for (size_t i = 0; i < esc_pins.size(); ++i) {
        bool ok = ledcAttachChannel(esc_pins[i], ONESHOT_FREQ,PWM_BITS,esc_ch[i]);
        if (!ok) {
            Serial.printf("Cannot attach pin %d to channel %d\n", esc_pins[i], esc_ch[i]);
            while (true) { blinker.start(5); }
        }
    }

    for (auto ch : esc_ch) ledcWriteChannel(ch, DUTY_MAX);
    delay(3000);
    for (auto ch : esc_ch) ledcWriteChannel(ch, DUTY_MIN);
    delay(3000);
}

void loop() {
    static uint16_t duty = DUTY_MIN;
    static int16_t  step = 4;           // ramp speed
    static uint8_t  motor0b = 0;
    static bool     atMin = true;

    duty += step;
    if (duty >= DUTY_MAX || duty <= DUTY_MIN) step = -step;

    if (duty <= DUTY_MIN && !atMin) {
        atMin = true;
        motor0b = (motor0b + 1) % esc_pins.size();
        blinker.start(motor0b + 1);                 // 1‑4 blinks
        Serial.printf("Motor %d\n", motor0b + 1);
    }
    if (duty > DUTY_MIN) atMin = false;

    ledcWriteChannel(esc_ch[motor0b], duty);

    blinker.update();

    delay(10);
}

[sliwowitz]

Hmmm. This looks like a PlatformIO issue. If I compile the same thing in Arduino IDE, it works, but I would very much like not to have to use Arduino IDE, as I'm used to my PlatformIO workflow (with remote builds and some automation which I want to later include in the project too). I'll investigate more.