Method to check for USB_VBUS

[jacky4566]

Is there a method to check for USB_VBUS?

I see it is tied to GPIO_PIN_PB2. I tried to read pin 27 but it just returns false.

My intention is to shutdown the device when USB is not connected.

[GrumpyOldPizza]

The USB device is shut down already as long as there is no USB_VBUS detected. So what you are asking for is already implemented.

[jacky4566]

Right but how do I check for that in my program? Otherwise nothing gets printed because the device is sleeping.

 void setup() {
   Serial.begin(9600);
 }

 void loop() {
   if (/*Check for USB*/) {
     Serial.println(STM32.getTemperature());
     delay(1000);
  } else {
     STM32.stop(1000);
   }
 }

[kriswiner]

VBUS = STM32L0.getVBUS();

On Wed, Oct 9, 2019 at 12:33 PM jacky4566 notifications@github.com wrote:

Right but how do I check for that in my program? Otherwise nothing gets printed because the device is sleeping.

void setup() { Serial.begin(9600); }

void loop() { if (/Check for USB/) { Serial.println(STM32.getTemperature()); delay(1000); } else { STM32.stop(1000); } }

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[jacky4566]

We are talking about the L4 here. That function doesn't exist in STM32.h

[jacky4566]

I found a workaround by changing the variant.cpp file for my board. Changing Null to GPIOB allows me to read the pin. Is there any disadvantage to doing this?

https://github.com/GrumpyOldPizza/arduino-STM32L4/blob/ac659033eadd50cfe001ba1590a1362b2d87bb76/variants/STM32L433CC-Butterfly/variant.cpp#L87

[kriswiner]

USBConnected = USBDevice.connected(); on L4...

[jacky4566]

Great that seems to work. This should be in the documentation.

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  digitalWrite(LED_BUILTIN, USBDevice.connected());
}