Adds support for USB device functionality for AT90USB and

ATU2/U4 series devices.

Support tested on a PJRC TEENSY2++ board with AT90USB1286.

Signed-off-by: Rob Lippert <roblip@gmail.com>



git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@9487 35acf78f-673a-0410-8e92-d51de3d6d3f4

6 files changed, 1406 insertions, 0 deletions

diff --git a/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.c b/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.c
new file mode 100644
index 000000000..a16f25305
--- /dev/null
+++ b/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.c
@@ -0,0 +1,75 @@
+/*
+    Copyright (C) 2015 Robert Lippert
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+#include "hal.h"
+
+/**
+ * @brief   PAL setup.
+ * @details Digital I/O ports static configuration as defined in @p board.h.
+ *          This variable is used by the HAL when initializing the PAL driver.
+ */
+#if HAL_USE_PAL || defined(__DOXYGEN__)
+const PALConfig pal_default_config =
+{
+#if defined(PORTA)
+  {VAL_PORTA, VAL_DDRA},
+#endif
+#if defined(PORTB)
+  {VAL_PORTB, VAL_DDRB},
+#endif
+#if defined(PORTC)
+  {VAL_PORTC, VAL_DDRC},
+#endif
+#if defined(PORTD)
+  {VAL_PORTD, VAL_DDRD},
+#endif
+#if defined(PORTE)
+  {VAL_PORTE, VAL_DDRE},
+#endif
+#if defined(PORTF)
+  {VAL_PORTF, VAL_DDRF},
+#endif
+#if defined(PORTG)
+  {VAL_PORTG, VAL_DDRG},
+#endif
+#if defined(PORTH)
+  {VAL_PORTH, VAL_DDRH},
+#endif
+#if defined(PORTJ)
+  {VAL_PORTJ, VAL_DDRJ},
+#endif
+#if defined(PORTK)
+  {VAL_PORTK, VAL_DDRK},
+#endif
+#if defined(PORTL)
+  {VAL_PORTL, VAL_DDRL},
+#endif
+};
+#endif /* HAL_USE_PAL */
+
+/**
+ * Board-specific initialization code.
+ */
+void boardInit(void) {
+
+  /*
+   * External interrupts setup, all disabled initially.
+   */
+  EICRA  = 0x00;
+  EICRB  = 0x00;
+  EIMSK  = 0x00;
+
+}
diff --git a/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.h b/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.h
new file mode 100644
index 000000000..7b20330ee
--- /dev/null
+++ b/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.h
@@ -0,0 +1,86 @@
+/*
+    Copyright (C) 2015 Robert Lippert
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+#ifndef BOARD_H_
+#define BOARD_H_
+
+/*
+ * Setup for the PJRC Teensy2++ board.
+ */
+
+/*
+ * Board identifier.
+ */
+#define BOARD_TEENSY_2PLUSPLUS
+#define BOARD_NAME "PJRC Teensy 2++"
+
+/* All inputs with pull-ups */
+#define VAL_DDRA  0x00
+#define VAL_PORTA 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRB  0x00
+#define VAL_PORTB 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRC  0x00
+#define VAL_PORTC 0xFF
+
+/* All inputs with pull-ups, LED on D6, serial TX1 on D3 */
+#define VAL_DDRD  0x48
+#define VAL_PORTD 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRE  0x00
+#define VAL_PORTE 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRF  0x00
+#define VAL_PORTF 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRG  0x00
+#define VAL_PORTG 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRH  0x00
+#define VAL_PORTH 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRJ  0x00
+#define VAL_PORTJ 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRK  0x00
+#define VAL_PORTK 0xFF
+
+/* All inputs with pull-ups */
+#define VAL_DDRL  0x00
+#define VAL_PORTL 0xFF
+
+#define BOARD_LED1        6
+
+#if !defined(_FROM_ASM_)
+#ifdef __cplusplus
+extern "C" {
+#endif
+  void boardInit(void);
+#ifdef __cplusplus
+}
+#endif
+#endif /* _FROM_ASM_ */
+
+#endif /* BOARD_H_ */
diff --git a/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.mk b/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.mk
new file mode 100644
index 000000000..244324067
--- /dev/null
+++ b/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.mk
@@ -0,0 +1,5 @@
+# List of all the board related files.
+BOARDSRC = ${CHIBIOS}/os/hal/boards/PJRC_TEENSY_2PLUSPLUS/board.c
+
+# Required include directories
+BOARDINC = ${CHIBIOS}/os/hal/boards/PJRC_TEENSY_2PLUSPLUS
diff --git a/os/hal/ports/AVR/hal_usb_lld.c b/os/hal/ports/AVR/hal_usb_lld.c
new file mode 100644
index 000000000..e6fb42f1e
--- /dev/null
+++ b/os/hal/ports/AVR/hal_usb_lld.c
@@ -0,0 +1,841 @@
+/*
+    Copyright (C) 2015 Robert Lippert
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+/**
+ * @file    usb_lld.c
+ * @brief   AVR USB subsystem low level driver source.
+ *
+ * @addtogroup USB
+ * @{
+ */
+
+#include "hal.h"
+
+#if (HAL_USE_USB == TRUE) || defined(__DOXYGEN__)
+
+#ifndef F_USB
+#define F_USB F_CPU
+#endif
+
+/*===========================================================================*/
+/* Driver local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported variables.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   USB1 driver identifier.
+ */
+#if (AVR_USB_USE_USB1 == TRUE) || defined(__DOXYGEN__)
+USBDriver USBD1;
+#endif
+
+/*===========================================================================*/
+/* Driver local variables and types.                                         */
+/*===========================================================================*/
+
+/**
+ * @brief   EP0 state.
+ * @note    It is an union because IN and OUT endpoints are never used at the
+ *          same time for EP0.
+ */
+static union {
+  /**
+   * @brief   IN EP0 state.
+   */
+  USBInEndpointState in;
+  /**
+   * @brief   OUT EP0 state.
+   */
+  USBOutEndpointState out;
+} ep0_state;
+
+/**
+ * @brief   EP0 initialization structure.
+ */
+static const USBEndpointConfig ep0config = {
+  USB_EP_MODE_TYPE_CTRL,
+  _usb_ep0setup,
+  _usb_ep0in,
+  _usb_ep0out,
+  0x40,
+  0x40,
+  &ep0_state.in,
+  &ep0_state.out
+};
+
+/*===========================================================================*/
+/* Driver local variables and types.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions.                                                   */
+/*===========================================================================*/
+
+#ifdef AVR_USB_PLL_OFF_IN_SUSPEND
+static __attribute__((unused)) void usb_pll_off(void)  {
+  PLLCSR = 0;
+}
+#endif
+
+static void usb_pll_on(void) {
+#if (F_USB == 8000000)
+  #if (defined(__AVR_AT90USB82__) || defined(__AVR_AT90USB162__) || \
+       defined(__AVR_ATmega8U2__) || defined(__AVR_ATmega16U2__) || \
+       defined(__AVR_ATmega32U2__))
+    #define PLL_VAL                0
+  #elif (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
+    #define PLL_VAL                0
+  #elif (defined(__AVR_AT90USB646__)  || defined(__AVR_AT90USB1286__))
+    #define PLL_VAL                ((0 << PLLP2) | (1 << PLLP1) | (1 << PLLP0))
+  #elif (defined(__AVR_AT90USB647__)  || defined(__AVR_AT90USB1287__))
+    #define PLL_VAL                ((0 << PLLP2) | (1 << PLLP1) | (1 << PLLP0))
+  #endif
+#elif (F_USB == 16000000)
+  #if (defined(__AVR_AT90USB82__) || defined(__AVR_AT90USB162__) || \
+       defined(__AVR_ATmega8U2__) || defined(__AVR_ATmega16U2__) || \
+       defined(__AVR_ATmega32U2__))
+    #define PLL_VAL                ((0 << PLLP2) | (0 << PLLP1) | (1 << PLLP0))
+  #elif (defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
+    #define PLL_VAL                (1 << PINDIV)
+  #elif (defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__))
+    #define PLL_VAL                ((1 << PLLP2) | (1 << PLLP1) | (0 << PLLP0))
+  #elif (defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__))
+    #define PLL_VAL                ((1 << PLLP2) | (0 << PLLP1) | (1 << PLLP0))
+  #endif
+#endif
+
+#ifndef PLL_VAL
+#error Could not determine PLL value, unsupported AVR USB model type
+#endif
+
+#ifdef PLLFRQ
+  /* This initializes PLL on supported devices for USB 48MHz *only* */
+  PLLFRQ = (0 << PDIV3) | (1 << PDIV2) | (0 << PDIV1) | (0 << PDIV0);
+#endif
+
+  PLLCSR = PLL_VAL;
+  PLLCSR = PLL_VAL | (1 << PLLE);
+}
+
+static int usb_pll_is_locked(void) {
+  return !!(PLLCSR & (1 << PLOCK));
+}
+
+/*===========================================================================*/
+/* Driver interrupt handlers and threads.                                    */
+/*===========================================================================*/
+
+/**
+ * @brief   USB general/OTG/device management event interrupt handler.
+ *
+ * @isr
+ */
+OSAL_IRQ_HANDLER(USB_GEN_vect) {
+  uint8_t usbint, udint;
+  USBDriver * const usbp = &USBD1;
+
+  OSAL_IRQ_PROLOGUE();
+
+  usbint = USBINT;
+  udint = UDINT;
+
+  if (usbint & (1 << VBUSTI)) {
+    /* Connected. */
+#ifdef AVR_USB_PLL_OFF_IN_SUSPEND
+    usb_pll_on();
+    while (!usb_pll_is_locked()) {}
+#endif  /* AVR_USB_PLL_OFF_IN_SUSPEND */
+
+    /* Attach to bus */
+    usb_lld_connect_bus(usbp);
+    USBINT &= ~(1 << VBUSTI);
+  }
+
+  /* USB bus SUSPEND condition handling.*/
+  if (udint & (1 << SUSPI)) {
+    /* Disable suspend interrupt, enable WAKEUP interrupt */
+    UDIEN |= (1 << WAKEUPE);
+    UDINT &= ~(1 << WAKEUPI);
+    UDIEN &= ~(1 << SUSPE);
+
+    /* Freeze the clock to reduce power consumption */
+    USBCON |= (1 << FRZCLK);
+#ifdef AVR_USB_PLL_OFF_IN_SUSPEND
+    usb_pll_off();
+#endif  /* AVR_USB_PLL_OFF_IN_SUSPEND */
+
+    /* Clear the interrupt */
+    UDINT &= ~(1 << SUSPI);
+
+    _usb_isr_invoke_event_cb(usbp, USB_EVENT_SUSPEND);
+  }
+
+  /* USB bus WAKEUP condition handling.*/
+  if (udint & (1 << WAKEUPI)) {
+#ifdef AVR_USB_PLL_OFF_IN_SUSPEND
+    usb_pll_on();
+    while (!usb_pll_is_locked()) {}
+#endif  /* AVR_USB_PLL_OFF_IN_SUSPEND */
+
+    /* Unfreeze the clock */
+    USBCON &= ~(1 << FRZCLK);
+
+    /* Clear & disable wakeup interrupt, enable suspend interrupt */
+    UDINT &= ~(1 << WAKEUPI);
+    UDIEN &= ~(1 << WAKEUPE);
+    UDIEN |= (1 << SUSPE);
+
+    _usb_isr_invoke_event_cb(usbp, USB_EVENT_WAKEUP);
+  }
+
+  /* USB bus RESUME condition handling.*/
+  if (udint & (1 << EORSMI)) {
+    UDINT &= ~(1 << EORSMI);
+    UDIEN &= ~(1 << EORSME);
+  }
+
+  /* USB bus reset condition handling.*/
+  if (udint & (1 << EORSTI)) {
+    UDINT &= ~(1 << EORSTI);
+
+    /* Clear & disable suspend interrupt, enable WAKEUP interrupt */
+    UDINT &= ~(1 << SUSPI);
+    UDIEN &= ~(1 << SUSPE);
+    UDIEN |= (1 << WAKEUPE);
+
+    /* Reinitialize EP0.  This is not mentioned in the datasheet but
+     * apparently is required. */
+    usb_lld_init_endpoint(usbp, 0);
+
+    _usb_isr_invoke_event_cb(usbp, USB_EVENT_RESET);
+  }
+
+  /* Start-Of-Frame handling, only if enabled */
+  if ((UDIEN & (1 << SOFE)) && (udint & (1 << SOFI))) {
+    _usb_isr_invoke_sof_cb(usbp);
+    UDINT &= ~(1 << SOFI);
+  }
+
+  OSAL_IRQ_EPILOGUE();
+}
+
+static void usb_fifo_write(USBDriver *usbp, usbep_t ep, size_t n) {
+  const USBEndpointConfig *epcp = usbp->epc[ep];
+  USBInEndpointState *isp = epcp->in_state;
+  syssts_t sts;
+  if (n == 0) {
+    isp->last_tx_size = 0;
+    return;
+  }
+
+  if (n > epcp->in_maxsize)
+    n = epcp->in_maxsize;
+  /* i is number of bytes remaining to transmit minus 1 (to handle 256b case) */
+  uint8_t i = n - 1;
+
+  /* Must lock for entire operation to ensure nothing changes the ENUM value */
+  sts = osalSysGetStatusAndLockX();
+  UENUM = ep & 0xf;
+  do {
+    UEDATX = *isp->txbuf++;
+  } while (i--);
+  isp->last_tx_size = n;
+  osalSysRestoreStatusX(sts);
+}
+
+static void usb_fifo_read(USBDriver *usbp, usbep_t ep, size_t n) {
+  const USBEndpointConfig *epcp = usbp->epc[ep];
+  USBOutEndpointState *osp = epcp->out_state;
+  syssts_t sts;
+  if (n == 0)
+    return;
+  if (n > epcp->out_maxsize)
+    n = epcp->out_maxsize;
+  // i is number of bytes remaining to receive minus 1 (to handle 256b case)
+  uint8_t i = n - 1;
+
+  /* Must lock for entire operation to ensure nothing changes the ENUM value */
+  sts = osalSysGetStatusAndLockX();
+  UENUM = ep & 0xf;
+  do {
+    *osp->rxbuf++ = UEDATX;
+  } while (i--);
+  osalSysRestoreStatusX(sts);
+}
+
+static void ep_isr(USBDriver *usbp, usbep_t ep) {
+  const USBEndpointConfig *epcp = usbp->epc[ep];
+  size_t n;
+  UENUM = ep & 0xf;
+
+  /* TODO: if stalling is needed/expected remove this check */
+  osalDbgAssert(!(UEINTX & (1 << STALLEDI)), "Endpoint stalled!");
+
+  if ((UEIENX & (1 << TXINE)) && (UEINTX & (1 << TXINI))) {
+    /* Ready to accept more IN data to transmit to host */
+    /* Update transaction counts to reflect newly transmitted bytes */
+    epcp->in_state->txcnt += epcp->in_state->last_tx_size;
+    n = epcp->in_state->txsize - epcp->in_state->txcnt;
+    if (n > 0) {
+      /* Transfer not completed, there are more packets to send. */
+      usb_fifo_write(usbp, ep, n);
+
+      /* Clear FIFOCON to send the data in the FIFO and switch bank */
+      UEINTX &= ~((1 << TXINI) | (1 << FIFOCON));
+      /* Enable the TX complete interrupt */
+      UEIENX |= (1 << TXINE);
+    } else {
+      /* Disable TXIN interrupt */
+      UEIENX &= ~(1 << TXINE);
+      /* Handshake interrupt status */
+      UEINTX &= ~(1 << TXINI);
+      _usb_isr_invoke_in_cb(usbp, ep);
+    }
+  } else if ((UEIENX & (1 << RXSTPE)) && (UEINTX & (1 << RXSTPI))) {
+    /* Received SETUP data */
+    /* Reset transaction state for endpoint */
+    epcp->in_state->txcnt = 0;
+    epcp->in_state->txsize = 0;
+    epcp->in_state->last_tx_size = 0;
+    /* Setup packets handling, setup packets are handled using a
+       specific callback.*/
+    _usb_isr_invoke_setup_cb(usbp, ep);
+  } else if ((UEIENX & (1 << RXOUTE)) && (UEINTX & (1 << RXOUTI))) {
+    /* Received OUT data from host */
+    if (ep == 0 && usbp->ep0state == USB_EP0_WAITING_STS) {
+      /* SETUP/control transaction complete, invoke the callback. */
+      UEIENX &= ~(1 << RXOUTE);
+      UEINTX &= ~((1 << RXOUTI) | (1 << FIFOCON));
+      _usb_isr_invoke_out_cb(usbp, ep);
+    } else {
+      /* Check the FIFO byte count to see how many bytes were received */
+      n = UEBCX;
+
+      usb_fifo_read(usbp, ep, n);
+
+      /* Transaction state update */
+      epcp->out_state->rxcnt += n;
+      epcp->out_state->rxsize -= n;
+      epcp->out_state->rxpkts -= 1;
+      if (n < epcp->out_maxsize || epcp->out_state->rxpkts == 0) {
+        /* Disable OUT interrupt */
+        UEIENX &= ~(1 << RXOUTE);
+        /* Mark OUT FIFO processed to allow more data to be received */
+        UEINTX &= ~((1 << RXOUTI) | (1 << FIFOCON));
+        /* Transfer complete, invokes the callback.*/
+        _usb_isr_invoke_out_cb(usbp, ep);
+      } else {
+        /* Mark OUT FIFO processed to allow more data to be received */
+        UEINTX &= ~((1 << RXOUTI) | (1 << FIFOCON));
+      }
+    }
+  }
+}
+
+/**
+ * @brief   USB communication event interrupt handler.
+ *
+ * @isr
+ */
+OSAL_IRQ_HANDLER(USB_COM_vect) {
+  USBDriver *usbp = &USBD1;
+  const uint8_t epnum_orig = UENUM;
+  uint8_t i;
+
+  OSAL_IRQ_PROLOGUE();
+
+  /* Figure out which endpoint(s) are interrupting */
+  for (i = 0; i < USB_MAX_ENDPOINTS; ++i) {
+    if (UEINT & (1 << i)) {
+      ep_isr(usbp, i);
+    }
+  }
+
+  /* Restore endpoint selector to pre-interrupt state */
+  UENUM = epnum_orig;
+
+  OSAL_IRQ_EPILOGUE();
+}
+
+/*===========================================================================*/
+/* Driver exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Low level USB driver initialization.
+ *
+ * @notapi
+ */
+void usb_lld_init(void) {
+#if AVR_USB_USE_USB1 == TRUE
+  /* Driver initialization.*/
+  usbObjectInit(&USBD1);
+
+  /* Start and lock the USB 48MHz PLL (takes ~100ms) */
+  usb_pll_on();
+  while (!usb_pll_is_locked()) {}
+#endif
+}
+
+/**
+ * @brief   Configures and activates the USB peripheral.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ *
+ * @notapi
+ */
+void usb_lld_start(USBDriver *usbp) {
+  if (usbp->state == USB_STOP) {
+    /* Enables the peripheral.*/
+#if AVR_USB_USE_USB1 == TRUE
+    if (&USBD1 == usbp) {
+      uint8_t i;
+      /*
+       * Workaround: disable pad drivers as first step in case bootloader left
+       * it on.  Otherwise VBUS detection interrupt will not trigger later.
+       */
+      USBCON &= ~(1 << OTGPADE);
+
+      /* Enable the internal 3.3V pad regulator */
+      UHWCON |= (1 << UVREGE);
+
+      /* Reset and disable all endpoints */
+      UERST = 0x7f;
+      UERST = 0;
+      for (i = 0; i < USB_MAX_ENDPOINTS; ++i){
+        UENUM   = i;
+        UEIENX  = 0;
+        UEINTX  = 0;
+        UECFG1X = 0;
+        UECONX &= ~(1 << EPEN);
+      }
+    }
+#endif
+    /* Reset procedure enforced on driver start.*/
+    _usb_reset(usbp);
+  }
+}
+
+/**
+ * @brief   Deactivates the USB peripheral.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ *
+ * @notapi
+ */
+void usb_lld_stop(USBDriver *usbp) {
+  if (usbp->state == USB_READY) {
+    /* Disables the peripheral.*/
+#if AVR_USB_USE_USB1 == TRUE
+    if (&USBD1 == usbp) {
+      /* Disable and clear transition interrupts */
+      USBCON &= ~((1 << VBUSTE) | (1 << IDTE));
+      USBINT = 0;
+
+      /* Disable and clear device interrupts */
+      UDIEN &= ~((1 << UPRSME) | (1 << EORSME) | (1 << WAKEUPE) | (1 << EORSTE)
+          | (1 << SOFE) | (1 << SUSPE));
+      UDINT = 0;
+
+      /* Freeze clock */
+      USBCON |= (1 << FRZCLK);
+
+      /* Disable USB logic */
+      USBCON &= ~(1 << USBE);
+    }
+#endif
+  }
+}
+
+/**
+ * @brief   USB low level reset routine.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ *
+ * @notapi
+ */
+void usb_lld_reset(USBDriver *usbp) {
+  /* Post-reset initialization.*/
+  /* Reset and enable via toggling the USB macro logic overall enable bit */
+  USBCON &= ~(1 << USBE);
+  USBCON |= (1 << USBE);
+
+  /* Unfreeze clock */
+  USBCON &= ~(1 << FRZCLK);
+
+  /* Set Device mode */
+  /* TODO: Support HOST/OTG mode if needed */
+  UHWCON |= (1 << UIMOD);
+
+  /* Set FULL 12mbps speed */
+  UDCON &= ~(1 << LSM);
+
+  /* Enable device pin interrupt */
+  USBCON |= (1 << VBUSTE);
+
+  /* EP0 initialization.*/
+  UERST |= (1 << 0);
+  UERST &= ~(1 << 0);
+  usbp->epc[0] = &ep0config;
+  usb_lld_init_endpoint(usbp, 0);
+
+  /* Enable device-level event interrupts */
+  UDINT &= ~(1 << SUSPI);
+  UDIEN = (1 << UPRSME) | (1 << EORSME) | (1 << WAKEUPE) | (1 << EORSTE)
+      | (1 << SUSPE);
+  /* The SOF interrupt is only enabled if a callback is defined for
+     this service because it is a high rate source. */
+  if (usbp->config->sof_cb != NULL)
+    UDIEN |= (1 << SOFE);
+
+  /* Set OTG PAD to on which will trigger VBUS transition if plugged in. */
+  USBCON |= (1 << OTGPADE);
+}
+
+/**
+ * @brief   Sets the USB address.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ *
+ * @notapi
+ */
+void usb_lld_set_address(USBDriver *usbp) {
+  UDADDR = (UDADDR & (1 << ADDEN)) | (usbp->address & 0x7F);
+
+  UDADDR |= (1 << ADDEN);
+}
+
+/**
+ * @brief   Enables an endpoint.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_init_endpoint(USBDriver *usbp, usbep_t ep) {
+  uint16_t size = 0;
+  const USBEndpointConfig *epcp = usbp->epc[ep];
+
+  /* Select this endpoint number for subsequent commands */
+  UENUM = ep & 0xf;
+
+  /* Enable endpoint to take out of reset */
+  UECONX |= (1 << EPEN);
+
+  UECFG1X = 0;
+  /* Set the endpoint type.*/
+  switch (epcp->ep_mode & USB_EP_MODE_TYPE) {
+  case USB_EP_MODE_TYPE_ISOC:
+    UECFG0X = (0 << EPTYPE1) | (1 << EPTYPE0);
+    break;
+  case USB_EP_MODE_TYPE_BULK:
+    UECFG0X = (1 << EPTYPE1) | (0 << EPTYPE0);
+    break;
+  case USB_EP_MODE_TYPE_INTR:
+    UECFG0X = (1 << EPTYPE1) | (1 << EPTYPE0);
+    break;
+  default:
+    UECFG0X = (0 << EPTYPE1) | (0 << EPTYPE0);
+  }
+  if ((epcp->ep_mode & USB_EP_MODE_TYPE) == USB_EP_MODE_TYPE_CTRL) {
+    /* CTRL endpoint */
+    osalDbgCheck(epcp->in_maxsize == epcp->out_maxsize);
+    size = epcp->in_maxsize;
+  } else {
+    osalDbgAssert(!(epcp->in_cb != NULL && epcp->out_cb != NULL),
+                  "On AVR each endpoint can be IN or OUT not both");
+
+    /* IN endpoint? */
+    if (epcp->in_cb != NULL) {
+      UECFG0X |= (1 << EPDIR);
+      size = epcp->in_maxsize;
+    }
+
+    /* OUT endpoint? */
+    if (epcp->out_cb != NULL) {
+      UECFG0X &= ~(1 << EPDIR);
+      size = epcp->out_maxsize;
+    }
+  }
+
+  /* Endpoint size and address initialization. */
+  switch (size) {
+    case 8: UECFG1X = (0 << EPSIZE0) | (1 << ALLOC); break;
+    case 16: UECFG1X = (1 << EPSIZE0) | (1 << ALLOC); break;
+    case 32: UECFG1X = (2 << EPSIZE0) | (1 << ALLOC); break;
+    case 64: UECFG1X = (3 << EPSIZE0) | (1 << ALLOC); break;
+    case 128:
+      osalDbgAssert(ep == 1, "Endpoint size of 128 bytes only valid for EP#1");
+      UECFG1X = (4 << EPSIZE0) | (1 << ALLOC); break;
+    case 256:
+      osalDbgAssert(ep == 1, "Endpoint size of 256 bytes only valid for EP#1");
+      UECFG1X = (5 << EPSIZE0) | (1 << ALLOC); break;
+    default:
+      osalDbgAssert(false, "Invalid size for USB endpoint");
+  }
+
+  UEIENX |=  (1 << RXSTPE)/* | (1 << RXOUTE)*/ | (1 << STALLEDE) ;
+
+  osalDbgAssert((UESTA0X & (1 << CFGOK)),
+                "Hardware reports endpoint config is INVALID");
+}
+
+/**
+ * @brief   Disables all the active endpoints except the endpoint zero.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ *
+ * @notapi
+ */
+void usb_lld_disable_endpoints(USBDriver *usbp) {
+  uint8_t i;
+  for (i = 1; i <= USB_MAX_ENDPOINTS; ++i) {
+    UENUM = i;
+    UECFG1X &= ~(1 << ALLOC);
+    UECONX &= ~(1 << EPEN);
+  }
+}
+
+/**
+ * @brief   Returns the status of an OUT endpoint.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ * @return              The endpoint status.
+ * @retval EP_STATUS_DISABLED The endpoint is not active.
+ * @retval EP_STATUS_STALLED  The endpoint is stalled.
+ * @retval EP_STATUS_ACTIVE   The endpoint is active.
+ *
+ * @notapi
+ */
+usbepstatus_t usb_lld_get_status_out(USBDriver *usbp, usbep_t ep) {
+  /* Select this endpoint number for subsequent commands */
+  UENUM = ep & 0xf;
+
+  if (!(UECONX & (1 << EPEN)))
+    return EP_STATUS_DISABLED;
+  if (UECONX & (1 << STALLRQ))
+    return EP_STATUS_STALLED;
+  return EP_STATUS_ACTIVE;
+}
+
+/**
+ * @brief   Returns the status of an IN endpoint.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ * @return              The endpoint status.
+ * @retval EP_STATUS_DISABLED The endpoint is not active.
+ * @retval EP_STATUS_STALLED  The endpoint is stalled.
+ * @retval EP_STATUS_ACTIVE   The endpoint is active.
+ *
+ * @notapi
+ */
+usbepstatus_t usb_lld_get_status_in(USBDriver *usbp, usbep_t ep) {
+  return usb_lld_get_status_out(usbp, ep);
+}
+
+/**
+ * @brief   Reads a setup packet from the dedicated packet buffer.
+ * @details This function must be invoked in the context of the @p setup_cb
+ *          callback in order to read the received setup packet.
+ * @pre     In order to use this function the endpoint must have been
+ *          initialized as a control endpoint.
+ * @post    The endpoint is ready to accept another packet.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ * @param[out] buf      buffer where to copy the packet data
+ *
+ * @notapi
+ */
+void usb_lld_read_setup(USBDriver *usbp, usbep_t ep, uint8_t *buf) {
+  uint8_t i;
+  /* Select this endpoint number for subsequent commands */
+  UENUM = ep & 0xf;
+
+  for (i = 0; i < 8; ++i) {
+    *buf++ = UEDATX;
+  }
+  /* Clear FIFOCON and RXSTPI to drain the setup packet data from the FIFO */
+  UEINTX &= ~((1 << FIFOCON) | (1 << RXSTPI));
+}
+
+/**
+ * @brief   Ends a SETUP transaction
+ * @details This function must be invoked in the context of the @p setup_cb
+ *          callback in order to finish an entire setup packet.
+ * @pre     In order to use this function the endpoint must have been
+ *          initialized as a control endpoint.
+ * @post    The endpoint is ready to accept another packet.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_end_setup(USBDriver *usbp, usbep_t ep) {
+  /* Select this endpoint number for subsequent commands */
+  UENUM = ep & 0xf;
+
+  if ((usbp->setup[0] & USB_RTYPE_DIR_MASK) == USB_RTYPE_DIR_DEV2HOST) {
+    /* Enable interrupt and wait for OUT packet */
+    usbp->epc[ep]->out_state->rxsize = 0;
+    usbp->epc[ep]->out_state->rxpkts = 1;
+
+    UEINTX &= ~((1 << FIFOCON) | (1 << RXOUTI));
+    UEIENX |= (1 << RXOUTE);
+  } else {
+    /* Enable interrupt and wait for IN packet */
+    usbp->epc[ep]->in_state->last_tx_size = 0;
+    usbp->epc[ep]->in_state->txcnt = 0;
+    usbp->epc[ep]->in_state->txsize = 0;
+
+    UEINTX &= ~((1 << FIFOCON) | (1 << TXINI));
+    UEIENX |= (1 << TXINE);
+  }
+}
+
+/**
+ * @brief   Starts a receive operation on an OUT endpoint.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_start_out(USBDriver *usbp, usbep_t ep) {
+  USBOutEndpointState *osp = usbp->epc[ep]->out_state;
+  syssts_t sts;
+
+  /* Initialize transfer by recording how many packets we expect to receive. */
+  if (osp->rxsize == 0)         /* Special case for zero sized packets.*/
+    osp->rxpkts = 1;
+  else
+    osp->rxpkts = (uint8_t)((osp->rxsize + usbp->epc[ep]->out_maxsize - 1) /
+                             usbp->epc[ep]->out_maxsize);
+
+  /* Select this endpoint number for subsequent commands */
+  /* Must lock for entire operation to ensure nothing changes the ENUM value */
+  sts = osalSysGetStatusAndLockX();
+  UENUM = ep & 0xf;
+
+  UEIENX |= (1 << RXOUTE);
+  osalSysRestoreStatusX(sts);
+}
+
+/**
+ * @brief   Starts a transmit operation on an IN endpoint.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_start_in(USBDriver *usbp, usbep_t ep) {
+  USBInEndpointState *isp = usbp->epc[ep]->in_state;
+  syssts_t sts;
+
+  /* Initialize transfer by filling FIFO with passed data. */
+  usb_fifo_write(usbp, ep, isp->txsize);
+
+  /* Select this endpoint number for subsequent commands */
+  /* Must lock for entire operation to ensure nothing changes the ENUM value */
+  sts = osalSysGetStatusAndLockX();
+  UENUM = ep & 0xf;
+
+  /* Clear FIFOCON to send the data in the FIFO and switch bank */
+  UEINTX &= ~((1 << TXINI) | (1 << FIFOCON));
+
+  /* Enable the TX complete interrupt */
+  UEIENX |= (1 << TXINE);
+
+  osalSysRestoreStatusX(sts);
+}
+
+/**
+ * @brief   Brings an OUT endpoint in the stalled state.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_stall_out(USBDriver *usbp, usbep_t ep) {
+  syssts_t sts;
+  (void)usbp;
+
+  /* Select this endpoint number for subsequent commands */
+  /* Must lock for entire operation to ensure nothing changes the ENUM value */
+  sts = osalSysGetStatusAndLockX();
+  UENUM = ep & 0xf;
+
+  UECONX |= (1 << STALLRQ);
+  osalSysRestoreStatusX(sts);
+}
+
+/**
+ * @brief   Brings an IN endpoint in the stalled state.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_stall_in(USBDriver *usbp, usbep_t ep) {
+  usb_lld_stall_out(usbp, ep);
+}
+
+/**
+ * @brief   Brings an OUT endpoint in the active state.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_clear_out(USBDriver *usbp, usbep_t ep) {
+  syssts_t sts;
+  (void)usbp;
+
+  /* Select this endpoint number for subsequent commands */
+  /* Must lock for entire operation to ensure nothing changes the ENUM value */
+  sts = osalSysGetStatusAndLockX();
+  UENUM = ep & 0xf;
+
+  UECONX |= (1 << STALLRQC);
+  osalSysRestoreStatusX(sts);
+}
+
+/**
+ * @brief   Brings an IN endpoint in the active state.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ *
+ * @notapi
+ */
+void usb_lld_clear_in(USBDriver *usbp, usbep_t ep) {
+  usb_lld_clear_out(usbp, ep);
+}
+
+#endif /* HAL_USE_USB == TRUE */
+
+/** @} */
diff --git a/os/hal/ports/AVR/hal_usb_lld.h b/os/hal/ports/AVR/hal_usb_lld.h
new file mode 100644
index 000000000..e47d38425
--- /dev/null
+++ b/os/hal/ports/AVR/hal_usb_lld.h
@@ -0,0 +1,398 @@
+/*
+    Copyright (C) 2015 Robert Lippert
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+/**
+ * @file    usb_lld.h
+ * @brief   AVR USB subsystem low level driver header.
+ *
+ * @addtogroup USB
+ * @{
+ */
+
+#ifndef _USB_LLD_H_
+#define _USB_LLD_H_
+
+#if (HAL_USE_USB == TRUE) || defined(__DOXYGEN__)
+
+#include "hal_usb.h"
+
+/*===========================================================================*/
+/* Driver constants.                                                         */
+/*===========================================================================*/
+
+/**
+ * @brief   Maximum endpoint address.
+ */
+#define USB_MAX_ENDPOINTS                   7
+
+/**
+ * @brief   Status stage handling method.
+ */
+#define USB_EP0_STATUS_STAGE                USB_EP0_STATUS_STAGE_HW
+
+/**
+ * @brief   The address is changed after IN packet is received.
+ */
+#define USB_SET_ADDRESS_MODE                USB_LATE_SET_ADDRESS
+
+/**
+ * @brief   Method for set address acknowledge.
+ */
+#define USB_SET_ADDRESS_ACK_HANDLING        USB_SET_ADDRESS_ACK_SW
+
+/*===========================================================================*/
+/* Driver pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/**
+ * @name    AVR configuration options
+ * @{
+ */
+/**
+ * @brief   USB driver enable switch.
+ * @details If set to @p TRUE the support for USB1 is included.
+ * @note    The default is @p FALSE.
+ */
+#if !defined(AVR_USB_USE_USB1) || defined(__DOXYGEN__)
+#define AVR_USB_USE_USB1                  FALSE
+#endif
+/** @} */
+
+/*
+ * If compiler supports named address spaces
+ * (see https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html)
+ * then mark our TX buf pointer as able to cover flash or SRAM to allow
+ * for storing/transmitting constants like USB descriptors in flash to save
+ * previous RAM space.
+ */
+#if !defined(AVR_USB_USE_NAMED_ADDRESS_SPACES) || defined(__DOXYGEN__)
+#define AVR_USB_USE_NAMED_ADDRESS_SPACES  FALSE
+#endif
+
+#if (AVR_USB_USE_NAMED_ADDRESS_SPACES == TRUE) && defined(__MEMX)
+#define AVR_USB_TX_BUF_ADDRESS_SPACE volatile __memx
+#else
+#define AVR_USB_TX_BUF_ADDRESS_SPACE
+#endif
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver data structures and types.                                         */
+/*===========================================================================*/
+
+typedef const AVR_USB_TX_BUF_ADDRESS_SPACE uint8_t *usbbufptr_t;
+
+/**
+ * @brief   Type of an IN endpoint state structure.
+ */
+typedef struct {
+  /**
+   * @brief   Requested transmit transfer size.
+   */
+  size_t                        txsize;
+  /**
+   * @brief   Transmitted bytes so far.
+   */
+  size_t                        txcnt;
+  /**
+   * @brief   Pointer to the transmission linear buffer.
+   */
+  usbbufptr_t                   txbuf;
+#if (USB_USE_WAIT == TRUE) || defined(__DOXYGEN__)
+  /**
+   * @brief   Waiting thread.
+   */
+  thread_reference_t            thread;
+#endif
+  /* End of the mandatory fields.*/
+  /**
+   * @brief   Number of expected bytes in the most recent transmission.
+   */
+  size_t                       last_tx_size;
+} USBInEndpointState;
+
+/**
+ * @brief   Type of an OUT endpoint state structure.
+ */
+typedef struct {
+  /**
+   * @brief   Requested receive transfer size.
+   */
+  size_t                        rxsize;
+  /**
+   * @brief   Received bytes so far.
+   */
+  size_t                        rxcnt;
+  /**
+   * @brief   Pointer to the receive linear buffer.
+   */
+  uint8_t                       *rxbuf;
+#if (USB_USE_WAIT == TRUE) || defined(__DOXYGEN__)
+  /**
+   * @brief   Waiting thread.
+   */
+  thread_reference_t            thread;
+#endif
+  /* End of the mandatory fields.*/
+  uint8_t                      rxpkts;
+} USBOutEndpointState;
+
+/**
+ * @brief   Type of an USB endpoint configuration structure.
+ * @note    Platform specific restrictions may apply to endpoints.
+ */
+typedef struct {
+  /**
+   * @brief   Type and mode of the endpoint.
+   */
+  uint32_t                      ep_mode;
+  /**
+   * @brief   Setup packet notification callback.
+   * @details This callback is invoked when a setup packet has been
+   *          received.
+   * @post    The application must immediately call @p usbReadPacket() in
+   *          order to access the received packet.
+   * @note    This field is only valid for @p USB_EP_MODE_TYPE_CTRL
+   *          endpoints, it should be set to @p NULL for other endpoint
+   *          types.
+   */
+  usbepcallback_t               setup_cb;
+  /**
+   * @brief   IN endpoint notification callback.
+   * @details This field must be set to @p NULL if the IN endpoint is not
+   *          used.
+   */
+  usbepcallback_t               in_cb;
+  /**
+   * @brief   OUT endpoint notification callback.
+   * @details This field must be set to @p NULL if the OUT endpoint is not
+   *          used.
+   */
+  usbepcallback_t               out_cb;
+  /**
+   * @brief   IN endpoint maximum packet size.
+   * @details This field must be set to zero if the IN endpoint is not
+   *          used.
+   */
+  uint16_t                      in_maxsize;
+  /**
+   * @brief   OUT endpoint maximum packet size.
+   * @details This field must be set to zero if the OUT endpoint is not
+   *          used.
+   */
+  uint16_t                      out_maxsize;
+  /**
+   * @brief   @p USBEndpointState associated to the IN endpoint.
+   * @details This structure maintains the state of the IN endpoint.
+   */
+  USBInEndpointState            *in_state;
+  /**
+   * @brief   @p USBEndpointState associated to the OUT endpoint.
+   * @details This structure maintains the state of the OUT endpoint.
+   */
+  USBOutEndpointState           *out_state;
+  /* End of the mandatory fields.*/
+} USBEndpointConfig;
+
+/**
+ * @brief   Type of an USB driver configuration structure.
+ */
+typedef struct {
+  /**
+   * @brief   USB events callback.
+   * @details This callback is invoked when an USB driver event is registered.
+   */
+  usbeventcb_t                  event_cb;
+  /**
+   * @brief   Device GET_DESCRIPTOR request callback.
+   * @note    This callback is mandatory and cannot be set to @p NULL.
+   */
+  usbgetdescriptor_t            get_descriptor_cb;
+  /**
+   * @brief   Requests hook callback.
+   * @details This hook allows to be notified of standard requests or to
+   *          handle non standard requests.
+   */
+  usbreqhandler_t               requests_hook_cb;
+  /**
+   * @brief   Start Of Frame callback.
+   */
+  usbcallback_t                 sof_cb;
+  /* End of the mandatory fields.*/
+} USBConfig;
+
+/**
+ * @brief   Structure representing an USB driver.
+ */
+struct USBDriver {
+  /**
+   * @brief   Driver state.
+   */
+  usbstate_t                    state;
+  /**
+   * @brief   Current configuration data.
+   */
+  const USBConfig               *config;
+  /**
+   * @brief   Bit map of the transmitting IN endpoints.
+   */
+  uint8_t                       transmitting;
+  /**
+   * @brief   Bit map of the receiving OUT endpoints.
+   */
+  uint8_t                       receiving;
+  /**
+   * @brief   Active endpoints configurations.
+   */
+  const USBEndpointConfig       *epc[USB_MAX_ENDPOINTS + 1];
+  /**
+   * @brief   Fields available to user, it can be used to associate an
+   *          application-defined handler to an IN endpoint.
+   * @note    The base index is one, the endpoint zero does not have a
+   *          reserved element in this array.
+   */
+  void                          *in_params[USB_MAX_ENDPOINTS];
+  /**
+   * @brief   Fields available to user, it can be used to associate an
+   *          application-defined handler to an OUT endpoint.
+   * @note    The base index is one, the endpoint zero does not have a
+   *          reserved element in this array.
+   */
+  void                          *out_params[USB_MAX_ENDPOINTS];
+  /**
+   * @brief   Endpoint 0 state.
+   */
+  usbep0state_t                 ep0state;
+  /**
+   * @brief   Next position in the buffer to be transferred through endpoint 0.
+   */
+  const AVR_USB_TX_BUF_ADDRESS_SPACE uint8_t *ep0next;
+  /**
+   * @brief   Number of bytes yet to be transferred through endpoint 0.
+   */
+  size_t                        ep0n;
+  /**
+   * @brief   Endpoint 0 end transaction callback.
+   */
+  usbcallback_t                 ep0endcb;
+  /**
+   * @brief   Setup packet buffer.
+   */
+  uint8_t                       setup[8];
+  /**
+   * @brief   Current USB device status.
+   */
+  uint16_t                      status;
+  /**
+   * @brief   Assigned USB address.
+   */
+  uint8_t                       address;
+  /**
+   * @brief   Current USB device configuration.
+   */
+  uint8_t                       configuration;
+#if defined(USB_DRIVER_EXT_FIELDS)
+  USB_DRIVER_EXT_FIELDS
+#endif
+  /* End of the mandatory fields.*/
+};
+
+/*===========================================================================*/
+/* Driver macros.                                                            */
+/*===========================================================================*/
+
+/**
+ * @brief   Returns the current frame number.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @return              The current frame number.
+ *
+ * @notapi
+ */
+#define usb_lld_get_frame_number(usbp) (UDFNUM)
+
+/**
+ * @brief   Returns the exact size of a receive transaction.
+ * @details The received size can be different from the size specified in
+ *          @p usbStartReceiveI() because the last packet could have a size
+ *          different from the expected one.
+ * @pre     The OUT endpoint must have been configured in transaction mode
+ *          in order to use this function.
+ *
+ * @param[in] usbp      pointer to the @p USBDriver object
+ * @param[in] ep        endpoint number
+ * @return              Received data size.
+ *
+ * @notapi
+ */
+#define usb_lld_get_transaction_size(usbp, ep)                              \
+  ((usbp)->epc[ep]->out_state->rxcnt)
+
+/**
+ * @brief   Connects the USB device.
+ *
+ * @api
+ */
+#define usb_lld_connect_bus(usbp) (UDCON &= ~(1 << DETACH))
+
+/**
+ * @brief   Disconnect the USB device.
+ *
+ * @api
+ */
+#define usb_lld_disconnect_bus(usbp) (UDCON |= (1 << DETACH))
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#if (AVR_USB_USE_USB1 == TRUE) && !defined(__DOXYGEN__)
+extern USBDriver USBD1;
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  void usb_lld_init(void);
+  void usb_lld_start(USBDriver *usbp);
+  void usb_lld_stop(USBDriver *usbp);
+  void usb_lld_reset(USBDriver *usbp);
+  void usb_lld_set_address(USBDriver *usbp);
+  void usb_lld_enable_address(USBDriver *usbp);
+  void usb_lld_init_endpoint(USBDriver *usbp, usbep_t ep);
+  void usb_lld_disable_endpoints(USBDriver *usbp);
+  usbepstatus_t usb_lld_get_status_in(USBDriver *usbp, usbep_t ep);
+  usbepstatus_t usb_lld_get_status_out(USBDriver *usbp, usbep_t ep);
+  void usb_lld_read_setup(USBDriver *usbp, usbep_t ep, uint8_t *buf);
+  void usb_lld_end_setup(USBDriver *usbp, usbep_t ep);
+  void usb_lld_start_out(USBDriver *usbp, usbep_t ep);
+  void usb_lld_start_in(USBDriver *usbp, usbep_t ep);
+  void usb_lld_stall_out(USBDriver *usbp, usbep_t ep);
+  void usb_lld_stall_in(USBDriver *usbp, usbep_t ep);
+  void usb_lld_clear_out(USBDriver *usbp, usbep_t ep);
+  void usb_lld_clear_in(USBDriver *usbp, usbep_t ep);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* HAL_USE_USB == TRUE */
+
+#endif /* _USB_LLD_H_ */
+
+/** @} */
diff --git a/os/hal/ports/AVR/platform.mk b/os/hal/ports/AVR/platform.mk
index 7181924bc..2b20b8a80 100644
--- a/os/hal/ports/AVR/platform.mk
+++ b/os/hal/ports/AVR/platform.mk
@@ -8,6 +8,7 @@ PLATFORMSRC = ${CHIBIOS}/os/hal/ports/AVR/hal_lld.c \
               ${CHIBIOS}/os/hal/ports/AVR/hal_gpt_lld.c \

               ${CHIBIOS}/os/hal/ports/AVR/hal_pwm_lld.c \

               ${CHIBIOS}/os/hal/ports/AVR/hal_icu_lld.c \

+              ${CHIBIOS}/os/hal/ports/AVR/hal_usb_lld.c \

               ${CHIBIOS}/os/hal/ports/AVR/hal_st_lld.c

 

 # Required include directories