Merge pull request #2134 from clhenry/non-bus-powered-re-enumeration

Non-bus-powered MSP430 support.
2025-03-14 13:21:13 +00:00 · 2024-04-15 23:14:10 +07:00 · 2024-04-15 23:14:10 +07:00 · fb21b6a67d
commit fb21b6a67d
parent d816a9bdf8 afb66a955c
12 changed files with 322 additions and 27 deletions
--- a/.github/workflows/build_msp430.yml
+++ b/.github/workflows/build_msp430.yml
@ -61,10 +61,11 @@ jobs:
        tar -C ~/cache/toolchain -xaf toolchain.tar.bz2

    - name: Set Toolchain Path
-      run: echo >> $GITHUB_PATH `echo ~/cache/toolchain/*/bin`
-
-    - name: Get Dependencies
-      run: python3 tools/get_deps.py ${{ matrix.family }}
+      run: |
+        echo >> $GITHUB_PATH `echo ~/cache/toolchain/*/bin`
+        sudo apt install -y ninja-build

    - name: Build
-      run: python3 tools/build_make.py ${{ matrix.family }}
+      run: |
+        python3 tools/get_deps.py ${{ matrix.family }}
+        python tools/build_cmake.py ${{ matrix.family }} -DCMAKE_BUILD_TYPE=MinSizeRel
--- a/.idea/cmake.xml
+++ b/.idea/cmake.xml
@ -2,8 +2,9 @@
 <project version="4">
  <component name="CMakeSharedSettings">
    <configurations>
-      <configuration PROFILE_NAME="pico" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=raspberry_pi_pico -DLOG=2" />
-      <configuration PROFILE_NAME="feather_rp2040" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=pico_sdk -DPICO_BOARD=adafruit_feather_rp2040 -DLOG=2 -DLOGGER=RTT -DMAX3421_HOST=1" />
+      <configuration PROFILE_NAME="pico" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=raspberry_pi_pico -DLOG=1" />
+      <configuration PROFILE_NAME="feather_rp2040" ENABLED="false" CONFIG_NAME="Debug" TOOLCHAIN_NAME="armgcc 11.2" GENERATION_OPTIONS="-DBOARD=pico_sdk -DPICO_BOARD=adafruit_feather_rp2040 -DLOG=2" />
+      <configuration PROFILE_NAME="feather_rp2040_max3421" ENABLED="false" CONFIG_NAME="Debug" TOOLCHAIN_NAME="armgcc 11.2" GENERATION_OPTIONS="-DBOARD=feather_rp2040_max3421 -DLOG=2" />
      <configuration PROFILE_NAME="metro_rp2040" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=pico_sdk -DPICO_BOARD=adafruit_metro_rp2040 -DLOG=2 -DMAX3421_HOST=1" />
      <configuration PROFILE_NAME="feather esp32s2" ENABLED="false" TOOLCHAIN_NAME="ESP-IDF" GENERATION_OPTIONS="-DBOARD=adafruit_feather_esp32s2 -DMAX3421_HOST=1 -DLOG=2">
        <ADDITIONAL_GENERATION_ENVIRONMENT>
@ -44,7 +45,7 @@
      <configuration PROFILE_NAME="metro_m0_express" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=metro_m0_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
      <configuration PROFILE_NAME="feather_m4_express" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=feather_m4_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
      <configuration PROFILE_NAME="metro_m4_express" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=metro_m4_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
-      <configuration PROFILE_NAME="feather_nrf52840_express" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=feather_nrf52840_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
+      <configuration PROFILE_NAME="feather_nrf52840_express" ENABLED="false" CONFIG_NAME="Debug" TOOLCHAIN_NAME="armgcc 11.2" GENERATION_OPTIONS="-DBOARD=feather_nrf52840_express -DLOG=3 -DLOGGER=RTT -DMAX3421_HOST=1" />
      <configuration PROFILE_NAME="pca10056" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=pca10056 -DLOG=3 -DLOGGER=RTT -DTRACE_ETM=1" />
      <configuration PROFILE_NAME="pca10095" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=pca10095 -DLOG=3 -DLOGGER=RTT -DTRACE_ETM=1" />
      <configuration PROFILE_NAME="metro m7 1011 sd" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=metro_m7_1011_sd -DLOG=3 -DLOGGER=RTT -DTRACE_ETM=1" />
@ -57,8 +58,10 @@
      <configuration PROFILE_NAME="ea4357" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=ea4357 -DLOG=3 -DLOGGER=RTT -DTRACE_ETM=1" />
      <configuration PROFILE_NAME="lpc54628" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=lpcxpresso54628 -DLOG=4 -DLOGGER=RTT" />
      <configuration PROFILE_NAME="lpc55s69" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=lpcxpresso55s69 -DLOG=4 -DLOGGER=RTT" />
-      <configuration PROFILE_NAME="mcxn947" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=mcxn947brk -DLOG=3 -DLOGGER=RTT" />
+      <configuration PROFILE_NAME="mcxn947brk" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=mcxn947brk -DLOG=3 -DLOGGER=RTT" />
+      <configuration PROFILE_NAME="frdm_mcxa153" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=frdm_mcxa153 -DLOG=3 -DLOGGER=RTT" />
      <configuration PROFILE_NAME="frdm_kl25z" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=frdm_kl25z -DLOG=3 -DLOGGER=RTT" />
+      <configuration PROFILE_NAME="frdm_k32l2a4s" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=frdm_k32l2a4s" />
      <configuration PROFILE_NAME="frdm_k64f" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=frdm_k64f -DLOG=2 -DLOGGER=RTT" />
      <configuration PROFILE_NAME="stm32f072disco" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=stm32f072disco" />
      <configuration PROFILE_NAME="stm32f103_mini_2" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=stm32f103_mini_2" />
@ -82,6 +85,7 @@
      <configuration PROFILE_NAME="uno_r4" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=uno_r4 -DLOG=4 -DLOGGER=RTT" />
      <configuration PROFILE_NAME="portenta_c33" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=portenta_c33 -DLOG=3" />
      <configuration PROFILE_NAME="lpcxpresso1769" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=lpcxpresso1769 -DLOG=3 -DLOGGER=RTT" />
+      <configuration PROFILE_NAME="msp430f5529" ENABLED="false" CONFIG_NAME="Debug" GENERATION_OPTIONS="-DBOARD=msp_exp430f5529lp" />
    </configurations>
  </component>
 </project>
--- a/examples/build_system/cmake/cpu/msp430.cmake
+++ b/examples/build_system/cmake/cpu/msp430.cmake
@ -0,0 +1,7 @@
+if (TOOLCHAIN STREQUAL "gcc")
+  set(FREERTOS_PORT GCC_MSP430F449 CACHE INTERNAL "")
+
+elseif (TOOLCHAIN STREQUAL "iar")
+  set(FREERTOS_PORT IAR_MSP430 CACHE INTERNAL "")
+
+endif ()
--- a/examples/build_system/cmake/toolchain/msp430_gcc.cmake
+++ b/examples/build_system/cmake/toolchain/msp430_gcc.cmake
@ -0,0 +1,52 @@
+set(CMAKE_SYSTEM_NAME Generic)
+
+if (NOT DEFINED CMAKE_C_COMPILER)
+  set(CMAKE_C_COMPILER "msp430-elf-gcc")
+endif ()
+
+if (NOT DEFINED CMAKE_CXX_COMPILER)
+  set(CMAKE_CXX_COMPILER "msp430-elf-g++")
+endif ()
+
+set(CMAKE_ASM_COMPILER ${CMAKE_C_COMPILER})
+
+set(CMAKE_SIZE "msp430-elf-size" CACHE FILEPATH "")
+set(CMAKE_OBJCOPY "msp430-elf-objcopy" CACHE FILEPATH "")
+set(CMAKE_OBJDUMP "msp430-elf-objdump" CACHE FILEPATH "")
+
+set_property(GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS FALSE)
+
+# Look for includes and libraries only in the target system prefix.
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+# pass TOOLCHAIN_CPU to
+set(CMAKE_TRY_COMPILE_PLATFORM_VARIABLES CMAKE_SYSTEM_PROCESSOR)
+
+include(${CMAKE_CURRENT_LIST_DIR}/../cpu/${CMAKE_SYSTEM_PROCESSOR}.cmake)
+
+# enable all possible warnings for building examples
+list(APPEND TOOLCHAIN_COMMON_FLAGS
+  -fdata-sections
+  -ffunction-sections
+  -fsingle-precision-constant
+  -fno-strict-aliasing
+  )
+
+list(APPEND TOOLCHAIN_EXE_LINKER_FLAGS
+  -Wl,--print-memory-usage
+  -Wl,--gc-sections
+  -Wl,--cref
+  )
+
+include(${CMAKE_CURRENT_LIST_DIR}/set_flags.cmake)
+
+# try_compile is cmake test compiling its own example,
+# pass -nostdlib to skip stdlib linking
+get_property(IS_IN_TRY_COMPILE GLOBAL PROPERTY IN_TRY_COMPILE)
+if (IS_IN_TRY_COMPILE)
+  set(CMAKE_C_LINK_FLAGS "${CMAKE_C_LINK_FLAGS} -nostdlib")
+  set(CMAKE_CXX_LINK_FLAGS "${CMAKE_CXX_LINK_FLAGS} -nostdlib")
+endif ()
--- a/examples/build_system/make/cpu/msp430.mk
+++ b/examples/build_system/make/cpu/msp430.mk
@ -0,0 +1,8 @@
+ifeq ($(TOOLCHAIN),gcc)
+  # nothing to add
+else ifeq ($(TOOLCHAIN),iar)
+  # nothing to add
+endif
+
+# For freeRTOS port source
+FREERTOS_PORTABLE_SRC ?= $(FREERTOS_PORTABLE_PATH)/GCC_MSP430F449
--- a/hw/bsp/family_support.cmake
+++ b/hw/bsp/family_support.cmake
@ -460,6 +460,21 @@ function(family_flash_dfu_util TARGET OPTION)
    )
 endfunction()

+function(family_flash_msp430flasher TARGET)
+  if (NOT DEFINED MSP430Flasher)
+    set(MSP430FLASHER MSP430Flasher)
+  endif ()
+
+  # set LD_LIBRARY_PATH to find libmsp430.so (directory containing MSP430Flasher)
+  find_program(MSP430FLASHER_PATH MSP430Flasher)
+  get_filename_component(MSP430FLASHER_PARENT_DIR "${MSP430FLASHER_PATH}" DIRECTORY)
+  add_custom_target(${TARGET}-msp430flasher
+    DEPENDS ${TARGET}
+    COMMAND ${CMAKE_COMMAND} -E env LD_LIBRARY_PATH=${MSP430FLASHER_PARENT_DIR}
+            ${MSP430FLASHER} -w $<TARGET_FILE_DIR:${TARGET}>/${TARGET}.hex -z [VCC]
+    )
+endfunction()
+
 #----------------------------------
 # Family specific
 #----------------------------------
--- a/hw/bsp/msp430/boards/msp_exp430f5529lp/board.cmake
+++ b/hw/bsp/msp430/boards/msp_exp430f5529lp/board.cmake
@ -0,0 +1,9 @@
+set(MCU_VARIANT msp430f5529)
+set(LD_FILE_GNU ${SDK_DIR}/msp430f5529.ld)
+
+function(update_board TARGET)
+  target_compile_definitions(${TARGET} INTERFACE
+    __MSP430F5529__
+    )
+
+endfunction()
--- a/hw/bsp/msp430/boards/msp_exp430f5529lp/board.mk
+++ b/hw/bsp/msp430/boards/msp_exp430f5529lp/board.mk
@ -0,0 +1,4 @@
+CFLAGS += \
+  -D__MSP430F5529__ \
+
+LD_FILE = ${SDK_DIR}/msp430f5529.ld
--- a/hw/bsp/msp430/family.cmake
+++ b/hw/bsp/msp430/family.cmake
@ -0,0 +1,84 @@
+include_guard()
+
+set(SDK_DIR ${TOP}/hw/mcu/ti/msp430/msp430-gcc-support-files/include)
+
+# include board specific
+include(${CMAKE_CURRENT_LIST_DIR}/boards/${BOARD}/board.cmake)
+
+# toolchain set up
+set(CMAKE_SYSTEM_PROCESSOR msp430 CACHE INTERNAL "System Processor")
+set(CMAKE_TOOLCHAIN_FILE ${TOP}/examples/build_system/cmake/toolchain/msp430_${TOOLCHAIN}.cmake)
+
+set(FAMILY_MCUS MSP430x5xx CACHE INTERNAL "")
+
+
+#------------------------------------
+# BOARD_TARGET
+#------------------------------------
+# only need to be built ONCE for all examples
+function(add_board_target BOARD_TARGET)
+  if (NOT TARGET ${BOARD_TARGET})
+    add_library(${BOARD_TARGET} INTERFACE)
+    target_compile_definitions(${BOARD_TARGET} INTERFACE
+      CFG_TUD_ENDPOINT0_SIZE=8
+      CFG_EXAMPLE_VIDEO_READONLY
+      CFG_EXAMPLE_MSC_READONLY
+      )
+    target_include_directories(${BOARD_TARGET} INTERFACE
+      ${CMAKE_CURRENT_FUNCTION_LIST_DIR}
+      ${SDK_DIR}
+      )
+
+    update_board(${BOARD_TARGET})
+
+    if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
+      target_link_options(${BOARD_TARGET} INTERFACE
+        "LINKER:--script=${LD_FILE_GNU}"
+        -L${SDK_DIR}
+        )
+    elseif (CMAKE_C_COMPILER_ID STREQUAL "IAR")
+      target_link_options(${BOARD_TARGET} INTERFACE
+        "LINKER:--config=${LD_FILE_IAR}"
+        )
+    endif ()
+  endif ()
+endfunction()
+
+
+#------------------------------------
+# Functions
+#------------------------------------
+function(family_configure_example TARGET RTOS)
+  family_configure_common(${TARGET} ${RTOS})
+
+  # Board target
+  add_board_target(board_${BOARD})
+
+  #---------- Port Specific ----------
+  # These files are built for each example since it depends on example's tusb_config.h
+  target_sources(${TARGET} PUBLIC
+    # BSP
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/family.c
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/../board.c
+    )
+  target_include_directories(${TARGET} PUBLIC
+    # family, hw, board
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/../../
+    ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/boards/${BOARD}
+    )
+
+  # Add TinyUSB target and port source
+  family_add_tinyusb(${TARGET} OPT_MCU_MSP430x5xx ${RTOS})
+  target_sources(${TARGET}-tinyusb PUBLIC
+    ${TOP}/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c
+    )
+  target_link_libraries(${TARGET}-tinyusb PUBLIC board_${BOARD})
+
+  # Link dependencies
+  target_link_libraries(${TARGET} PUBLIC board_${BOARD} ${TARGET}-tinyusb)
+
+  # Flashing
+  family_add_bin_hex(${TARGET})
+  family_flash_msp430flasher(${TARGET})
+endfunction()
--- a/hw/bsp/msp430/family.mk
+++ b/hw/bsp/msp430/family.mk
@ -2,21 +2,21 @@ CROSS_COMPILE = msp430-elf-
 DEPS_SUBMODULES += hw/mcu/ti
 SKIP_NANOLIB = 1

+SDK_DIR = hw/mcu/ti/msp430/msp430-gcc-support-files/include
+
+include $(TOP)/$(BOARD_PATH)/board.mk
+
 CFLAGS += \
-  -D__MSP430F5529__ \
  -DCFG_TUSB_MCU=OPT_MCU_MSP430x5xx \
 	-DCFG_EXAMPLE_MSC_READONLY \
 	-DCFG_TUD_ENDPOINT0_SIZE=8

-# All source paths should be relative to the top level.
-LD_FILE = hw/mcu/ti/msp430/msp430-gcc-support-files/include/msp430f5529.ld
-LDINC += $(TOP)/hw/mcu/ti/msp430/msp430-gcc-support-files/include
-LDFLAGS += $(addprefix -L,$(LDINC))
+LDFLAGS += -L${TOP}/${SDK_DIR}

 SRC_C += src/portable/ti/msp430x5xx/dcd_msp430x5xx.c

 INC += \
-	$(TOP)/hw/mcu/ti/msp430/msp430-gcc-support-files/include \
+	${TOP}/${SDK_DIR} \
 	$(TOP)/$(BOARD_PATH)

 # export for libmsp430.so to same installation
--- a/src/portable/st/stm32_fsdev/dcd_stm32_fsdev.c
+++ b/src/portable/st/stm32_fsdev/dcd_stm32_fsdev.c
@ -535,14 +535,14 @@ static void dcd_ep_ctr_rx_handler(uint32_t wIstr)
   * - Software should ensure that a small delay is included before accessing the SRAM contents. This delay
   * should be 800 ns in Full Speed mode and 6.4 μs in Low Speed mode
   * - Since H5 can run up to 250Mhz -> 1 cycle = 4ns. Per errata, we need to wait 200 cycles. Though executing code
-   * also takes time, so we'll wait 40 cycles (count = 20).
+   * also takes time, so we'll wait 60 cycles (count = 20).
   * - Since Low Speed mode is not supported/popular, we will ignore it for now.
   *
   * Note: this errata also seems to apply to G0, U5, H5 etc.
   */
  volatile uint32_t cycle_count = 20; // defined as PCD_RX_PMA_CNT in stm32 hal_driver
  while (cycle_count > 0U) {
-    cycle_count--; // each count take 2 cycle (1 cycle for sub, 1 cycle for compare/jump)
+    cycle_count--; // each count take 3 cycles (1 for sub, jump, and compare)
  }
 #endif

--- a/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c
+++ b/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c
@ -94,7 +94,8 @@ static void bus_reset(void)
  USBOEPCNT_0 &= ~NAK;
  USBIEPCNT_0 &= ~NAK;

-  USBCTL |= FEN; // Enable responding to packets.
+  // Enable responding to packets.
+  USBCTL |= FEN;

  // Dedicated buffers in hardware for SETUP and EP0, no setup needed.
  // Now safe to respond to SETUP packets.
@ -103,6 +104,28 @@ static void bus_reset(void)
  USBKEYPID = 0;
 }

+// Controls reset behavior of the USB module on receipt of a bus reset event.
+// - enable: When true, bus reset events will cause a reset the USB module.
+static void enable_functional_reset(const bool enable)
+{
+  // Check whether or not the USB configuration registers were
+  // locked prior to this function being called so that, if
+  // necessary, the lock state can be restored on exit.
+  bool unlocked = (USBKEYPID == 0xA528) ? true : false;
+
+  if(!unlocked) USBKEYPID = USBKEY;
+
+  if(enable)
+  {
+    USBCTL |= FRSTE;
+  }
+  else
+  {
+    USBCTL &= ~FRSTE;
+  }
+
+  if(!unlocked) USBKEYPID = 0;
+}

 /*------------------------------------------------------------------*/
 /* Controller API
@ -131,11 +154,14 @@ void dcd_init (uint8_t rhport)

  USBVECINT = 0;

-  // Enable reset and wait for it before continuing.
-  USBIE |= RSTRIE;
-
-  // Enable pullup.
-  USBCNF |= PUR_EN;
+  if(USBPWRCTL & USBBGVBV) {// Bus power detected?
+    USBPWRCTL |= VBOFFIE;   // Enable bus-power-removed interrupt.
+    USBIE |= RSTRIE;        // Enable reset and wait for it before continuing.
+    USBCNF |= PUR_EN;       // Enable pullup.
+  } else {
+    USBPWRCTL |= VBONIE;    // Enable bus-power-applied interrupt.
+    USBCNF &= ~USB_EN;      // Disable USB module until bus power is detected.
+  }

  USBKEYPID = 0;
 }
@ -610,14 +636,76 @@ static void handle_setup_packet(void)
    _setup_packet[i] = setup_buf[i];
  }

-  // Clearing SETUPIFG by reading USBVECINT does not set NAK, so now that we
-  // have a SETUP packet, force NAKs until tinyusb can handle the SETUP
-  // packet and prepare for a new xfer.
+  // Force NAKs until tinyusb can handle the SETUP packet and prepare for a new xfer.
  USBIEPCNT_0 |= NAK;
  USBOEPCNT_0 |= NAK;
+
+  // Clear SETUPIFG to avoid handling in the USBVECINT switch statement.
+  // When handled there the NAKs applied to the endpoints above are
+  // cleared by hardware and the host will receive stale/duplicate data.
+  //
+  // Excerpt from MSP430x5xx and MSP430x6xx Family User's Guide:
+  //
+  // "...the SETUPIFG is cleared upon reading USBIV. In addition, the NAK on
+  // input endpoint 0 and output endpoint 0 is also cleared."
+  USBIEPCNF_0 &= ~UBME; // Errata USB10 workaround.
+  USBOEPCNF_0 &= ~UBME; // Errata USB10 workaround.
+  USBIFG &= ~SETUPIFG;
+  USBIEPCNF_0 |= UBME;  // Errata USB10 workaround.
+  USBOEPCNF_0 |= UBME;  // Errata USB10 workaround.
  dcd_event_setup_received(0, (uint8_t*) &_setup_packet[0], true);
 }

+#if CFG_TUSB_OS == OPT_OS_NONE
+TU_ATTR_ALWAYS_INLINE static inline void tu_delay(uint32_t ms) {
+  // msp430 can run up to 25Mhz -> 40ns per cycle. 1 ms = 25000 cycles
+  // each loop need 4 cycle: 1 sub, 1 cmp, 1 jump, 1 nop
+  volatile uint32_t cycles = (25000 * ms) >> 2;
+  while (cycles > 0) {
+    cycles--;
+    asm("nop");
+  }
+}
+#else
+#define tu_delay(ms) osal_task_delay(ms)
+#endif
+
+static void handle_bus_power_event(void *param) {
+  (void) param;
+
+  tu_delay(5);                 // Bus power settling delay.
+
+  USBKEYPID = USBKEY;
+
+  if(USBPWRCTL & USBBGVBV) {          // Event caused by application of bus power.
+    USBPWRCTL |= VBOFFIE;             // Enable bus-power-removed interrupt.
+    USBPLLDIVB = USBPLLDIVB;          // For some reason the PLL will *NOT* lock unless the divider
+                                      // register is re-written. The assumption here is that this
+                                      // register was already properly configured during board-level
+                                      // initialization.
+    USBPLLCTL |= (UPLLEN | UPFDEN);   // Enable the PLL.
+
+    uint16_t attempts = 0;
+    do {                              // Poll the PLL, checking for a successful lock.
+      USBPLLIR = 0;
+      tu_delay(1);
+      attempts++;
+    } while ((attempts < 10) && (USBPLLIR != 0));
+
+    // A successful lock is indicated by all PLL-related interrupt flags being cleared.
+    if(!USBPLLIR) {
+      dcd_init(0);                    // Re-initialize the USB module.
+    }
+  } else {                            // Event caused by removal of bus power.
+    USBPWRCTL |= VBONIE;              // Enable bus-power-applied interrupt.
+    USBPLLCTL &= ~(UPLLEN | UPFDEN);  // Disable the PLL.
+    USBCNF = 0;                       // Disable the USB module.
+    dcd_event_bus_signal(0, DCD_EVENT_UNPLUGGED, false);
+  }
+
+  USBKEYPID = 0;
+}
+
 void dcd_int_handler(uint8_t rhport)
 {
  (void) rhport;
@ -628,6 +716,7 @@ void dcd_int_handler(uint8_t rhport)

  if(setup_status)
  {
+    enable_functional_reset(true);
    handle_setup_packet();
  }

@ -646,11 +735,32 @@ void dcd_int_handler(uint8_t rhport)

  switch(curr_vector)
  {
+    case USBVECINT_NONE:
+      break;
+
    case USBVECINT_RSTR:
+      enable_functional_reset(false); // Errata USB4 workaround.
      bus_reset();
      dcd_event_bus_reset(0, TUSB_SPEED_FULL, true);
      break;

+    case USBVECINT_PWR_VBUSOn:
+    case USBVECINT_PWR_VBUSOff: {
+      USBKEYPID = USBKEY;
+      // Prevent (possibly) unstable power from generating spurious interrupts.
+      USBPWRCTL &= ~(VBONIE | VBOFFIE);
+      USBKEYPID = 0;
+
+      dcd_event_t event;
+
+      event.rhport = 0;
+      event.event_id = USBD_EVENT_FUNC_CALL;
+      event.func_call.func = handle_bus_power_event;
+
+      dcd_event_handler(&event, true);
+      }
+      break;
+
    // Clear the (hardware-enforced) NAK on EP 0 after a SETUP packet
    // is received. At this point, even though the hardware is no longer
    // forcing NAKs, the EP0 NAK bits should still be set to avoid
@ -675,10 +785,12 @@ void dcd_int_handler(uint8_t rhport)
      break;

    case USBVECINT_INPUT_ENDPOINT0:
+      enable_functional_reset(true);
      transmit_packet(0);
      break;

    case USBVECINT_OUTPUT_ENDPOINT0:
+      enable_functional_reset(true);
      receive_packet(0);
      break;

@ -710,7 +822,6 @@ void dcd_int_handler(uint8_t rhport)

    default:
      while(true);
-      break;
  }

 }