examples/stm32: do not enable vbus detect by default, it doesn't work on all boards.

1 files changed, 5 insertions, 7 deletions

diff --git a/examples/stm32l4/src/bin/usb_serial.rs b/examples/stm32l4/src/bin/usb_serial.rs
index a378cdc6b..ed9671d0f 100644
--- a/examples/stm32l4/src/bin/usb_serial.rs
+++ b/examples/stm32l4/src/bin/usb_serial.rs
@@ -47,13 +47,11 @@ async fn main(_spawner: Spawner) {
     let mut ep_out_buffer = [0u8; 256];
     let mut config = embassy_stm32::usb::Config::default();
 
-    // Enable vbus_detection
-    // Note: some boards don't have this wired up and might not require it,
-    // as they are powered through usb!
-    // If you hang on boot, try setting this to "false"!
-    // See https://embassy.dev/book/dev/faq.html#_the_usb_examples_are_not_working_on_my_board_is_there_anything_else_i_need_to_configure
-    // for more information
-    config.vbus_detection = true;
+    // Do not enable vbus_detection. This is a safe default that works in all boards.
+    // However, if your USB device is self-powered (can stay powered on if USB is unplugged), you need
+    // to enable vbus_detection to comply with the USB spec. If you enable it, the board
+    // has to support it or USB won't work at all. See docs on `vbus_detection` for details.
+    config.vbus_detection = false;
 
     let driver = Driver::new_fs(p.USB_OTG_FS, Irqs, p.PA12, p.PA11, &mut ep_out_buffer, config);