Add comment on vbus_detection to all USB examples

1 files changed, 13 insertions, 0 deletions

diff --git a/examples/stm32f4/src/bin/usb_ethernet.rs b/examples/stm32f4/src/bin/usb_ethernet.rs
index d2cbeea1b..284c74564 100644
--- a/examples/stm32f4/src/bin/usb_ethernet.rs
+++ b/examples/stm32f4/src/bin/usb_ethernet.rs
@@ -40,6 +40,11 @@ bind_interrupts!(struct Irqs {
     HASH_RNG => rng::InterruptHandler<peripherals::RNG>;
 });
 
+// If you are trying this and your USB device doesn't connect, the most
+// common issues are the RCC config and vbus_detection
+//
+// 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.
 #[embassy_executor::main]
 async fn main(spawner: Spawner) {
     info!("Hello World!");
@@ -71,7 +76,15 @@ async fn main(spawner: Spawner) {
     static OUTPUT_BUFFER: StaticCell<[u8; 256]> = StaticCell::new();
     let ep_out_buffer = &mut OUTPUT_BUFFER.init([0; 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;
+
     let driver = Driver::new_fs(p.USB_OTG_FS, Irqs, p.PA12, p.PA11, ep_out_buffer, config);
 
     // Create embassy-usb Config