diff --git a/ports/samd/Makefile b/ports/samd/Makefile
index 12223e6ded..95d0f3bd18 100644
--- a/ports/samd/Makefile
+++ b/ports/samd/Makefile
@@ -55,6 +55,7 @@ INC += -I$(TOP)/lib/asf4/$(MCU_SERIES_LOWER)/hpl/tc
 INC += -I$(TOP)/lib/asf4/$(MCU_SERIES_LOWER)/include
 INC += -I$(TOP)/lib/asf4/$(MCU_SERIES_LOWER)/include/pio
 INC += -I$(TOP)/lib/tinyusb/src
+INC += -I$(TOP)/shared/tinyusb/
 
 MAKE_PINS = boards/make-pins.py
 BOARD_PINS = $(BOARD_DIR)/pins.csv
@@ -117,7 +118,7 @@ SRC_C += \
 	samd_qspiflash.c \
 	samd_soc.c \
 	samd_spiflash.c \
-	tusb_port.c \
+	usbd.c \
 
 SHARED_SRC_C += \
 	drivers/dht/dht.c \
@@ -133,7 +134,8 @@ SHARED_SRC_C += \
 	shared/runtime/sys_stdio_mphal.c \
 	shared/timeutils/timeutils.c \
 	shared/tinyusb/mp_cdc_common.c \
-	shared/tinyusb/mp_usbd.c
+	shared/tinyusb/mp_usbd.c \
+	shared/tinyusb/mp_usbd_descriptor.c \
 
 ASF4_SRC_C += $(addprefix lib/asf4/$(MCU_SERIES_LOWER)/,\
 	hal/src/hal_atomic.c \
diff --git a/ports/samd/mcu/samd21/mpconfigmcu.mk b/ports/samd/mcu/samd21/mpconfigmcu.mk
index 35f442d869..b3092837cb 100644
--- a/ports/samd/mcu/samd21/mpconfigmcu.mk
+++ b/ports/samd/mcu/samd21/mpconfigmcu.mk
@@ -1,5 +1,7 @@
 CFLAGS_MCU += -mtune=cortex-m0plus -mcpu=cortex-m0plus -msoft-float
 
+CFLAGS_MCU += -DCFG_TUSB_MCU=OPT_MCU_SAMD21
+
 MPY_CROSS_MCU_ARCH = armv6m
 
 MICROPY_HW_CODESIZE ?= 184K
diff --git a/ports/samd/mcu/samd51/mpconfigmcu.mk b/ports/samd/mcu/samd51/mpconfigmcu.mk
index c706331aca..0201bacffe 100644
--- a/ports/samd/mcu/samd51/mpconfigmcu.mk
+++ b/ports/samd/mcu/samd51/mpconfigmcu.mk
@@ -1,5 +1,7 @@
 CFLAGS_MCU += -mtune=cortex-m4 -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -mfloat-abi=hard
 
+CFLAGS_MCU += -DCFG_TUSB_MCU=OPT_MCU_SAMD51
+
 MPY_CROSS_MCU_ARCH = armv7m
 
 MICROPY_HW_CODESIZE ?= 368K
diff --git a/ports/samd/mpconfigport.h b/ports/samd/mpconfigport.h
index 91a7c1a10d..497ca9a870 100644
--- a/ports/samd/mpconfigport.h
+++ b/ports/samd/mpconfigport.h
@@ -62,6 +62,13 @@
 #define MICROPY_HW_ENABLE_USBDEV            (1)
 #define MICROPY_HW_USB_CDC_1200BPS_TOUCH    (1)
 
+#if MICROPY_HW_ENABLE_USBDEV
+// Enable USB-CDC serial port
+#ifndef MICROPY_HW_USB_CDC
+#define MICROPY_HW_USB_CDC (1)
+#endif
+#endif
+
 // Control over Python builtins
 #define MICROPY_PY_BUILTINS_BYTES_HEX       (1)
 #define MICROPY_PY_BUILTINS_MEMORYVIEW      (1)
@@ -141,6 +148,15 @@
 
 #define MP_STATE_PORT MP_STATE_VM
 
+// Miscellaneous settings
+
+#ifndef MICROPY_HW_USB_VID
+#define MICROPY_HW_USB_VID (0xf055)
+#endif
+#ifndef MICROPY_HW_USB_PID
+#define MICROPY_HW_USB_PID (0x9802)
+#endif
+
 // Additional entries for use with pendsv_schedule_dispatch.
 #ifndef MICROPY_BOARD_PENDSV_ENTRIES
 #define MICROPY_BOARD_PENDSV_ENTRIES
diff --git a/ports/samd/tusb_port.c b/ports/samd/tusb_port.c
deleted file mode 100644
index e56ef0fd6a..0000000000
--- a/ports/samd/tusb_port.c
+++ /dev/null
@@ -1,122 +0,0 @@
-/*
- * This file is part of the MicroPython project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2019 Damien P. George
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#include "samd_soc.h"
-#include "tusb.h"
-
-#ifndef MICROPY_HW_USB_VID
-#define MICROPY_HW_USB_VID (0xf055)
-#define MICROPY_HW_USB_PID (0x9802)
-#endif
-
-#define USBD_DESC_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN)
-#define USBD_MAX_POWER_MA (250)
-
-#define USBD_ITF_CDC (0) // needs 2 interfaces
-#define USBD_ITF_MAX (2)
-
-#define USBD_CDC_EP_CMD (0x81)
-#define USBD_CDC_EP_OUT (0x02)
-#define USBD_CDC_EP_IN (0x82)
-#define USBD_CDC_CMD_MAX_SIZE (8)
-#define USBD_CDC_IN_OUT_MAX_SIZE (64)
-
-#define USBD_STR_0 (0x00)
-#define USBD_STR_MANUF (0x01)
-#define USBD_STR_PRODUCT (0x02)
-#define USBD_STR_SERIAL (0x03)
-#define USBD_STR_CDC (0x04)
-
-// Note: descriptors returned from callbacks must exist long enough for transfer to complete
-
-static const tusb_desc_device_t usbd_desc_device = {
-    .bLength = sizeof(tusb_desc_device_t),
-    .bDescriptorType = TUSB_DESC_DEVICE,
-    .bcdUSB = 0x0200,
-    .bDeviceClass = TUSB_CLASS_MISC,
-    .bDeviceSubClass = MISC_SUBCLASS_COMMON,
-    .bDeviceProtocol = MISC_PROTOCOL_IAD,
-    .bMaxPacketSize0 = CFG_TUD_ENDOINT0_SIZE,
-    .idVendor = MICROPY_HW_USB_VID,
-    .idProduct = MICROPY_HW_USB_PID,
-    .bcdDevice = 0x0100,
-    .iManufacturer = USBD_STR_MANUF,
-    .iProduct = USBD_STR_PRODUCT,
-    .iSerialNumber = USBD_STR_SERIAL,
-    .bNumConfigurations = 1,
-};
-
-static const uint8_t usbd_desc_cfg[USBD_DESC_LEN] = {
-    TUD_CONFIG_DESCRIPTOR(1, USBD_ITF_MAX, USBD_STR_0, USBD_DESC_LEN,
-        TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, USBD_MAX_POWER_MA),
-
-    TUD_CDC_DESCRIPTOR(USBD_ITF_CDC, USBD_STR_CDC, USBD_CDC_EP_CMD,
-        USBD_CDC_CMD_MAX_SIZE, USBD_CDC_EP_OUT, USBD_CDC_EP_IN, USBD_CDC_IN_OUT_MAX_SIZE),
-};
-
-static const char *const usbd_desc_str[] = {
-    [USBD_STR_MANUF] = "MicroPython",
-    [USBD_STR_PRODUCT] = "Board in FS mode",
-    [USBD_STR_SERIAL] = "000000000000", // TODO
-    [USBD_STR_CDC] = "Board CDC",
-};
-
-const uint8_t *tud_descriptor_device_cb(void) {
-    return (const uint8_t *)&usbd_desc_device;
-}
-
-const uint8_t *tud_descriptor_configuration_cb(uint8_t index) {
-    (void)index;
-    return usbd_desc_cfg;
-}
-
-const uint16_t *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
-    #define DESC_STR_MAX (20)
-    static uint16_t desc_str[DESC_STR_MAX];
-
-    uint8_t len;
-    if (index == 0) {
-        desc_str[1] = 0x0409; // supported language is English
-        len = 1;
-    } else {
-        if (index >= sizeof(usbd_desc_str) / sizeof(usbd_desc_str[0])) {
-            return NULL;
-        }
-        const char *str = usbd_desc_str[index];
-        for (len = 0; len < DESC_STR_MAX - 1 && str[len]; ++len) {
-            desc_str[1 + len] = str[len];
-        }
-    }
-
-    // first byte is length (including header), second byte is string type
-    desc_str[0] = (TUSB_DESC_STRING << 8) | (2 * len + 2);
-
-    return desc_str;
-}
-
-void USB_Handler_wrapper(void) {
-    tud_int_handler(0);
-}
diff --git a/ports/samd/tusb_config.h b/ports/samd/usbd.c
similarity index 64%
rename from ports/samd/tusb_config.h
rename to ports/samd/usbd.c
index 07fa680cbb..90f2e1bfd9 100644
--- a/ports/samd/tusb_config.h
+++ b/ports/samd/usbd.c
@@ -3,7 +3,7 @@
  *
  * The MIT License (MIT)
  *
- * Copyright (c) 2019 Damien P. George
+ * Copyright (c) 2023 Angus Gratton
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -23,25 +23,24 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-#ifndef MICROPY_INCLUDED_SAMD_TUSB_CONFIG_H
-#define MICROPY_INCLUDED_SAMD_TUSB_CONFIG_H
 
-// Common configuration
+#include "py/mpconfig.h"
+
+#if MICROPY_HW_ENABLE_USBDEV
+
+#include "mp_usbd.h"
+#include "string.h"
+#include "tusb.h"
+
+#define SERIAL_TODO "000000000000" // TODO
+
+void mp_usbd_port_get_serial_number(char *serial_buf) {
+    MP_STATIC_ASSERT(sizeof(SERIAL_TODO) <= MICROPY_HW_USB_DESC_STR_MAX);
+    strcpy(serial_buf, SERIAL_TODO);
+}
+
+void USB_Handler_wrapper(void) {
+    tud_int_handler(0);
+}
 
-#if defined(MCU_SAMD21)
-#define CFG_TUSB_MCU                OPT_MCU_SAMD21
-#elif defined(MCU_SAMD51)
-#define CFG_TUSB_MCU                OPT_MCU_SAMD51
 #endif
-#define CFG_TUSB_RHPORT0_MODE       OPT_MODE_DEVICE
-#define CFG_TUSB_MEM_SECTION
-#define CFG_TUSB_MEM_ALIGN          TU_ATTR_ALIGNED(4)
-
-// Device configuration
-
-#define CFG_TUD_ENDOINT0_SIZE       (64)
-#define CFG_TUD_CDC                 (1)
-#define CFG_TUD_CDC_RX_BUFSIZE      (64)
-#define CFG_TUD_CDC_TX_BUFSIZE      (64)
-
-#endif // MICROPY_INCLUDED_SAMD_TUSB_CONFIG_H