2 files changed, 29 insertions, 14 deletions

diff --git a/embassy-usb/src/builder.rs b/embassy-usb/src/builder.rs
index e1bf8041f..6c42b07dc 100644
--- a/embassy-usb/src/builder.rs
+++ b/embassy-usb/src/builder.rs
@@ -10,11 +10,25 @@ use crate::{Handler, Interface, UsbDevice, MAX_INTERFACE_COUNT, STRING_INDEX_CUS
 #[derive(Debug, Copy, Clone)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[non_exhaustive]
+/// Allows Configuring the Bcd USB version below 2.1
+pub enum UsbVersion {
+    Two = 0x0200,
+    TwoOne = 0x0210,
+}
+
+#[derive(Debug, Copy, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
 /// Configuration used when creating [`UsbDevice`].
 pub struct Config<'a> {
     pub(crate) vendor_id: u16,
     pub(crate) product_id: u16,
 
+    /// Device BCD USB version.
+    ///
+    /// Default: `0x0210` ("2.1")
+    pub bcd_usb: UsbVersion,
+
     /// Device class code assigned by USB.org. Set to `0xff` for vendor-specific
     /// devices that do not conform to any class.
     ///
@@ -108,6 +122,7 @@ impl<'a> Config<'a> {
             vendor_id: vid,
             product_id: pid,
             device_release: 0x0010,
+            bcd_usb: UsbVersion::TwoOne,
             manufacturer: None,
             product: None,
             serial_number: None,
diff --git a/embassy-usb/src/descriptor.rs b/embassy-usb/src/descriptor.rs
index 06ebe0481..e9a6fd79a 100644
--- a/embassy-usb/src/descriptor.rs
+++ b/embassy-usb/src/descriptor.rs
@@ -325,12 +325,12 @@ pub(crate) fn device_descriptor(config: &Config) -> [u8; 18] {
     [
         18,   // bLength
         0x01, // bDescriptorType
-        0x10,
-        0x02,                     // bcdUSB 2.1
-        config.device_class,      // bDeviceClass
-        config.device_sub_class,  // bDeviceSubClass
-        config.device_protocol,   // bDeviceProtocol
-        config.max_packet_size_0, // bMaxPacketSize0
+        config.bcd_usb as u8,
+        (config.bcd_usb as u16 >> 8) as u8, // bcdUSB
+        config.device_class,                // bDeviceClass
+        config.device_sub_class,            // bDeviceSubClass
+        config.device_protocol,             // bDeviceProtocol
+        config.max_packet_size_0,           // bMaxPacketSize0
         config.vendor_id as u8,
         (config.vendor_id >> 8) as u8, // idVendor
         config.product_id as u8,
@@ -352,14 +352,14 @@ pub(crate) fn device_qualifier_descriptor(config: &Config) -> [u8; 10] {
     [
         10,   // bLength
         0x06, // bDescriptorType
-        0x10,
-        0x02,                     // bcdUSB 2.1
-        config.device_class,      // bDeviceClass
-        config.device_sub_class,  // bDeviceSubClass
-        config.device_protocol,   // bDeviceProtocol
-        config.max_packet_size_0, // bMaxPacketSize0
-        1,                        // bNumConfigurations
-        0,                        // Reserved
+        config.bcd_usb as u8,
+        (config.bcd_usb as u16 >> 8) as u8, // bcdUSB
+        config.device_class,                // bDeviceClass
+        config.device_sub_class,            // bDeviceSubClass
+        config.device_protocol,             // bDeviceProtocol
+        config.max_packet_size_0,           // bMaxPacketSize0
+        1,                                  // bNumConfigurations
+        0,                                  // Reserved
     ]
 }