ESP32-C3 How to know if USB console (GPIO18, GPIO19) is plugged in?

[arnaudmz]

Hi there.

I'd like to adapt the behaviour of my application depending on wether the native USB console is plugged or not.

Is there a software-based way to know this?
Do I have to use an extra GPIO plugged on the VUSB (with resistors to lower the voltage) ?

Regards,

Arnaud

[ESP_Sprite]

I'm not sure if we have software for that, but the hardware makes the latest SOF received available in a register. While USB is connected, that number should increase at exactly once every millisecond. You could use that.

[arnaudmz]

@ESP_Sprite: sounds good enough, I can live with this.

Could you provide a link to some documentation where to look for this register and give it a go?

Arnaud

[arnaudmz]

Found it in the meantime:

Code: Select all

USB_SERIAL_JTAG_FRAM_NUM_REG

does the trick very well.

Thanks.

[dongrigorio]

For esp32-c3 returns zero if usb is not connected, otherwise returns a positive integer (10).

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int is_plugged_usb(void){
    uint32_t *aa = USB_SERIAL_JTAG_FRAM_NUM_REG;
    uint32_t first = *aa;
    vTaskDelay(pdMS_TO_TICKS(10));
    return (int) (*aa - first);
}

[kscheff]

With framework 5.2.1

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*(uint_32_t*)USB_SERIAL_JTAG_FRAM_NUM_REG

returns a 12-bit counter, counting down.
In my observation the counter runs in average with ~36.5ms.
When no USB was connect it shows 0, it stops counting down when USB is unplugged.

[mano1979]

For esp32-c3 returns zero if usb is not connected, otherwise returns a positive integer (10).

Code: Select all

int is_plugged_usb(void){
    uint32_t *aa = USB_SERIAL_JTAG_FRAM_NUM_REG;
    uint32_t first = *aa;
    vTaskDelay(pdMS_TO_TICKS(10));
    return (int) (*aa - first);
}

How to use this? I am trying to implement it in my arduino sketch, but i get errors.

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'USB_SERIAL_JTAG_FRAM_NUM_REG ' was not declared in this scope.

Where should it be placed?