no success setting a GPIO

[mzimmers]

Hi all -

Working on the ESP32-DevKitC and trying to toggle a GPIO pin.

Here's the initialization code:

Code: Select all

#define BUZZER_NUM (GPIO_NUM_5)
#define BUZZER_PIN (GPIO_SEL_5)
...
Buzzer::Buzzer()
{
    // create the queue for receiving button push notifications.
    m_buzzerQueue = xQueueCreate(10, sizeof(BuzzerQueueEntry));
    // configure the io_conf structure.
    io_conf.pin_bit_mask = BUZZER_PIN;
    io_conf.intr_type = static_cast<gpio_int_type_t>(GPIO_PIN_INTR_DISABLE);
    io_conf.mode = GPIO_MODE_OUTPUT;
    io_conf.pull_up_en = GPIO_PULLUP_DISABLE;
    io_conf.pull_down_en = GPIO_PULLDOWN_ENABLE;
    //configure GPIO with the given settings
    esp_err_t err = gpio_config(&io_conf);
    if (err != ESP_OK)
    {
        ESP_LOGE(TAG, "error %d configuring GPIO.", err);
    }
}

Here's the code that does the work:

Code: Select all

void Buzzer::buzzer_task()
{
    BuzzerQueueEntry entry;
    esp_err_t err;
    uint32_t level;
    while (1)
    {
        entry.value = 0; // reset between queue reads.

        // look for a change request from our queue. Process if present.
        if (xQueueReceive(m_buzzerQueue, &entry, portMAX_DELAY) == pdTRUE)
        {
            if (entry.value > 0)
            {
                // turn buzzer on
                ESP_LOGI(TAG, "turning buzzer on.");
                level = 1;
                err = gpio_set_level(BUZZER_NUM, level);
                if (err != ESP_OK)
                {
                    ESP_LOGE(TAG, "error enabling GPIO.");
                }
                ESP_LOGI(TAG, "GPIO level is %d", gpio_get_level(BUZZER_NUM));
            }
            else
            {
                // turn buzzer off
                ESP_LOGI(TAG, "turning buzzer off.");
                level = 0;
                err = gpio_set_level(BUZZER_NUM, level);
                if (err != ESP_OK)
                {
                    ESP_LOGE(TAG, "error disabling GPIO.");
                }
                ESP_LOGI(TAG, "GPIO level is %d", gpio_get_level(BUZZER_NUM));
            }
        }
    }
}

and here's the call:

Code: Select all

    BuzzerQueueEntry buzz;
    buzz.value = 1;
    xQueueSendToBack(buzzQueue, &buzz, 0);
    vTaskDelay(20);
    buzz.value = 0;
    xQueueSendToBack(buzzQueue, &buzz, 0);

It produces this output:

I (386) Buzzer: turning buzzer on.
I (386) Buzzer: GPIO level is 0
I (586) Buzzer: turning buzzer off.
I (586) Buzzer: GPIO level is 0

(No error messages indicating that my get/set calls are failing.)
Any ideas what I'm doing wrong?

Thanks...

[kolban]

Its likely that the semantic for reading from a GPIO pin defined as output is undefined or simply false (0). I think I saw a post in the last few weeks asking if it were possible to read the value of a previously written GPIO pin and the answer was yes but it used some mysterious (to me) settings. Another post suggested that since you set the GPIO value previously, you already know the signal on it and could save that value in some variable and just reference it.

[mzimmers]

Bingo. I changed it to input and output, and it reads properly on the eval board. (I'll change it back on the target board.) Thanks, Neil.