Merge pull request #194 from cr1901/msp430f5529

[WIP] MSP430 Support

17 files changed, 933 insertions, 14 deletions

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8005c114d..a663f3ceb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -39,8 +39,11 @@ jobs:
         npm install --global xpm
         xpm install --global @xpack-dev-tools/arm-none-eabi-gcc@latest
         xpm install --global @xpack-dev-tools/riscv-none-embed-gcc@latest
+        wget http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/MSPGCC/8_3_0_0/exports/msp430-gcc-8.3.0.16_linux64.tar.bz2 -O /tmp/msp430-gcc.tar.bz2
+        tar -C $HOME -xaf /tmp/msp430-gcc.tar.bz2
         echo "::add-path::`echo $HOME/opt/xPacks/@xpack-dev-tools/arm-none-eabi-gcc/*/.content/bin`"
         echo "::add-path::`echo $HOME/opt/xPacks/@xpack-dev-tools/riscv-none-embed-gcc/*/.content/bin`"
+        echo "::add-path::`echo $HOME/msp430-gcc-*_linux64/bin`"
       
     - name: Checkout TinyUSB
       uses: actions/checkout@v2
diff --git a/examples/device/board_test/src/tusb_config.h b/examples/device/board_test/src/tusb_config.h
index 2f2a4deeb..1a52cc348 100644
--- a/examples/device/board_test/src/tusb_config.h
+++ b/examples/device/board_test/src/tusb_config.h
@@ -64,7 +64,9 @@
 // DEVICE CONFIGURATION
 //--------------------------------------------------------------------
 
+#ifndef CFG_TUD_ENDPOINT0_SIZE
 #define CFG_TUD_ENDPOINT0_SIZE   64
+#endif
 
 //------------- CLASS -------------//
 #define CFG_TUD_CDC             0
diff --git a/examples/device/cdc_msc_freertos/.skip.MCU_MSP430x5xx b/examples/device/cdc_msc_freertos/.skip.MCU_MSP430x5xx
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/examples/device/cdc_msc_freertos/.skip.MCU_MSP430x5xx
diff --git a/examples/device/dfu_rt/src/tusb_config.h b/examples/device/dfu_rt/src/tusb_config.h
index 96c3a2468..d1efcdab5 100644
--- a/examples/device/dfu_rt/src/tusb_config.h
+++ b/examples/device/dfu_rt/src/tusb_config.h
@@ -51,7 +51,9 @@
 // DEVICE CONFIGURATION
 //--------------------------------------------------------------------
 
+#ifndef CFG_TUD_ENDPOINT0_SIZE
 #define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
 
 //------------- CLASS -------------//
 
diff --git a/examples/device/net_lwip_webserver/.skip.MCU_MSP430x5xx b/examples/device/net_lwip_webserver/.skip.MCU_MSP430x5xx
new file mode 100644
index 000000000..17600f062
--- /dev/null
+++ b/examples/device/net_lwip_webserver/.skip.MCU_MSP430x5xx
@@ -0,0 +1 @@
+too many warnings for 16-bit integer overflow
diff --git a/examples/device/net_lwip_webserver/Makefile b/examples/device/net_lwip_webserver/Makefile
index a153c30be..fa93cf87f 100644
--- a/examples/device/net_lwip_webserver/Makefile
+++ b/examples/device/net_lwip_webserver/Makefile
@@ -17,6 +17,8 @@ INC += \
 # Example source
 EXAMPLE_SOURCE += $(wildcard src/*.c)
 SRC_C += $(addprefix $(CURRENT_PATH)/, $(EXAMPLE_SOURCE))
+
+# lwip sources
 SRC_C += \
   lib/lwip/src/core/altcp.c \
   lib/lwip/src/core/altcp_alloc.c \
diff --git a/examples/device/usbtmc/src/tusb_config.h b/examples/device/usbtmc/src/tusb_config.h
index 5dddc2c46..b6a40355e 100644
--- a/examples/device/usbtmc/src/tusb_config.h
+++ b/examples/device/usbtmc/src/tusb_config.h
@@ -51,7 +51,9 @@
 // DEVICE CONFIGURATION
 //--------------------------------------------------------------------
 
+#ifndef CFG_TUD_ENDPOINT0_SIZE
 #define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
 
 //------------- CLASS -------------//
 
diff --git a/examples/make.mk b/examples/make.mk
index 3c2db88c4..d22c72e18 100644
--- a/examples/make.mk
+++ b/examples/make.mk
@@ -3,10 +3,12 @@
 #
 
 # Compiler
-ifeq ($(BOARD), fomu)
-CROSS_COMPILE = riscv-none-embed-
+ifeq ($(BOARD), msp_exp430f5529lp)
+  CROSS_COMPILE = msp430-elf-
+else ifeq ($(BOARD), fomu)
+  CROSS_COMPILE = riscv-none-embed-
 else
-CROSS_COMPILE = arm-none-eabi-
+  CROSS_COMPILE = arm-none-eabi-
 endif
 CC = $(CROSS_COMPILE)gcc
 CXX = $(CROSS_COMPILE)g++
diff --git a/examples/rules.mk b/examples/rules.mk
index e51703aa7..0343391cb 100644
--- a/examples/rules.mk
+++ b/examples/rules.mk
@@ -30,10 +30,14 @@ INC += $(TOP)/src
 
 #
 CFLAGS += $(addprefix -I,$(INC))
-LDFLAGS += $(CFLAGS) -fshort-enums -Wl,-T,$(TOP)/$(LD_FILE) -Wl,[email protected] -Wl,-cref -Wl,-gc-sections -specs=nosys.specs -specs=nano.specs
+ifeq ($(BOARD), msp_exp430f5529lp)
+  LDFLAGS += $(CFLAGS) -fshort-enums -Wl,-T,$(TOP)/$(LD_FILE) -Wl,[email protected] -Wl,-cref -Wl,-gc-sections
+else
+  LDFLAGS += $(CFLAGS) -fshort-enums -Wl,-T,$(TOP)/$(LD_FILE) -Wl,[email protected] -Wl,-cref -Wl,-gc-sections -specs=nosys.specs -specs=nano.specs
+endif
 ASFLAGS += $(CFLAGS)
 
-# Assembly files can be name with upper case .S, convert it to .s 
+# Assembly files can be name with upper case .S, convert it to .s
 SRC_S := $(SRC_S:.S=.s)
 
 # Due to GCC LTO bug https://bugs.launchpad.net/gcc-arm-embedded/+bug/1747966
@@ -66,8 +70,8 @@ $(BUILD)/$(BOARD)-firmware.elf: $(OBJ)
 $(BUILD)/$(BOARD)-firmware.bin: $(BUILD)/$(BOARD)-firmware.elf
 	@echo CREATE $@
 	@$(OBJCOPY) -O binary $^ $@
-	
-$(BUILD)/$(BOARD)-firmware.hex: $(BUILD)/$(BOARD)-firmware.elf	
+
+$(BUILD)/$(BOARD)-firmware.hex: $(BUILD)/$(BOARD)-firmware.elf
 	@echo CREATE $@
 	@$(OBJCOPY) -O ihex $^ $@
 
@@ -114,7 +118,7 @@ clean:
 # Flash binary using Jlink
 ifeq ($(OS),Windows_NT)
   JLINKEXE = JLink.exe
-else 
+else
   JLINKEXE = JLinkExe
 endif
 
diff --git a/hw/bsp/board.c b/hw/bsp/board.c
index 7c0654346..364027d58 100644
--- a/hw/bsp/board.c
+++ b/hw/bsp/board.c
@@ -25,6 +25,13 @@
 
 #include "board.h"
 
+#if defined(__MSP430__)
+  #define sys_write   write
+  #define sys_read    read
+#else
+  #define sys_write   _write
+  #define sys_read    _read
+#endif
 //--------------------------------------------------------------------+
 // MACRO TYPEDEF CONSTANT ENUM DECLARATION
 //--------------------------------------------------------------------+
@@ -44,13 +51,13 @@
 
 // newlib read()/write() retarget
 
-TU_ATTR_USED int _write (int fhdl, const void *buf, size_t count)
+TU_ATTR_USED int sys_write (int fhdl, const void *buf, size_t count)
 {
   (void) fhdl;
   return board_uart_write(buf, count);
 }
 
-TU_ATTR_USED int _read (int fhdl, char *buf, size_t count)
+TU_ATTR_USED int sys_read (int fhdl, char *buf, size_t count)
 {
   (void) fhdl;
   return board_uart_read((uint8_t*) buf, count);
diff --git a/hw/bsp/msp_exp430f5529lp/board.mk b/hw/bsp/msp_exp430f5529lp/board.mk
new file mode 100644
index 000000000..13e3b7217
--- /dev/null
+++ b/hw/bsp/msp_exp430f5529lp/board.mk
@@ -0,0 +1,33 @@
+CFLAGS += \
+  -D__MSP430F5529__ \
+  -DCFG_TUSB_MCU=OPT_MCU_MSP430x5xx \
+	-DCFG_EXAMPLE_MSC_READONLY \
+	-DCFG_TUD_ENDPOINT0_SIZE=8
+
+#-mmcu=msp430f5529
+
+# 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))
+
+INC += $(TOP)/hw/mcu/ti/msp430/msp430-gcc-support-files/include
+
+# For TinyUSB port source
+VENDOR = ti
+CHIP_FAMILY = msp430x5xx
+
+# export for libmsp430.so to same installation
+ifneq ($(OS),Windows_NT)
+export LD_LIBRARY_PATH=$(dir $(shell which MSP430Flasher))
+endif
+
+# flash target using TI MSP430-Flasher
+# http://www.ti.com/tool/MSP430-FLASHER
+# Please add its installation dir to PATH
+flash: $(BUILD)/$(BOARD)-firmware.hex
+	MSP430Flasher -w $< -z [VCC]
+
+# flash target using mspdebug.
+flash-mspdebug: $(BUILD)/$(BOARD)-firmware.elf
+	$(MSPDEBUG) tilib "prog $<" --allow-fw-update
diff --git a/hw/bsp/msp_exp430f5529lp/msp_exp430f5529lp.c b/hw/bsp/msp_exp430f5529lp/msp_exp430f5529lp.c
new file mode 100644
index 000000000..bcae4b09e
--- /dev/null
+++ b/hw/bsp/msp_exp430f5529lp/msp_exp430f5529lp.c
@@ -0,0 +1,214 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ *
+ * 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.
+ *
+ * This file is part of the TinyUSB stack.
+ */
+
+#include "../board.h"
+
+#include "msp430.h"
+
+#define LED_PORT              P1OUT
+#define LED_PIN               BIT0
+#define LED_STATE_ON          1
+
+#define BUTTON_PORT           P1IN
+#define BUTTON_PIN            BIT1
+#define BUTTON_STATE_ACTIVE   0
+
+uint32_t cnt = 0;
+
+static void SystemClock_Config(void)
+{
+  WDTCTL = WDTPW + WDTHOLD; // Disable watchdog.
+
+  // Increase VCore to level 2- required for 16 MHz operation on this MCU.
+  PMMCTL0 = PMMPW + PMMCOREV_2;
+
+  UCSCTL3 = SELREF__XT2CLK; // FLL is fed by XT2.
+
+  // XT1 used for ACLK (default- not used in this demo)
+  P5SEL |= BIT4; // Required to enable XT1
+  // Loop until XT1 fault flag is cleared.
+  do
+  {
+    UCSCTL7 &= ~XT1LFOFFG;
+  }while(UCSCTL7 & XT1LFOFFG);
+
+  // XT2 is 4 MHz an external oscillator, use PLL to boost to 16 MHz.
+  P5SEL |= BIT2; // Required to enable XT2.
+  // Loop until XT2 fault flag is cleared
+  do
+  {
+    UCSCTL7 &= ~XT2OFFG;
+  }while(UCSCTL7 & XT2OFFG);
+
+  // Kickstart the DCO into the correct frequency range, otherwise a
+  // fault will occur.
+  // FIXME: DCORSEL_6 should work according to datasheet params, but generates
+  // a fault. I am not sure why it faults.
+  UCSCTL1 = DCORSEL_7;
+  UCSCTL2 = FLLD_2 + 3; // DCO freq = D * (N + 1) * (FLLREFCLK / n)
+                        // DCOCLKDIV freq = (N + 1) * (FLLREFCLK / n)
+                        // N = 3, D = 2, thus DCO freq = 32 MHz.
+
+  // MCLK configured for 16 MHz using XT2.
+  // SMCLK configured for 8 MHz using XT2.
+  UCSCTL4 |= SELM__DCOCLKDIV + SELS__DCOCLKDIV;
+  UCSCTL5 |= DIVM__16 + DIVS__2;
+
+  // Now wait till everything's stabilized.
+  do
+  {
+    UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + DCOFFG);
+    SFRIFG1 &= ~OFIFG;
+  }while(SFRIFG1 & OFIFG);
+
+  // Configure Timer A to use SMCLK as a source. Count 1000 ticks at 1 MHz.
+  TA0CCTL0 |= CCIE;
+  TA0CCR0 = 999; // 1000 ticks.
+  TA0CTL |= TASSEL_2 + ID_3 + MC__UP; // Use SMCLK, divide by 8, start timer.
+
+  // Initialize USB power and PLL.
+  USBKEYPID = USBKEY;
+
+  // VUSB enabled automatically.
+  // Wait two milliseconds to stabilize, per manual recommendation.
+  uint32_t ms_elapsed = board_millis();
+  do
+  {
+    while((board_millis() - ms_elapsed) < 2);
+  }while(!(USBPWRCTL & USBBGVBV));
+
+  // USB uses XT2 (4 MHz) directly. Enable the PLL.
+  USBPLLDIVB |= USBPLL_SETCLK_4_0;
+  USBPLLCTL |= (UPFDEN | UPLLEN);
+
+  // Wait until PLL locks. Check every 2ms, per manual.
+  ms_elapsed = board_millis();
+  do
+  {
+    USBPLLIR &= ~USBOOLIFG;
+    while((board_millis() - ms_elapsed) < 2);
+  }while(USBPLLIR & USBOOLIFG);
+
+  USBKEYPID = 0;
+}
+
+uint32_t wait = 0;
+
+void board_init(void)
+{
+  __bis_SR_register(GIE); // Enable interrupts.
+  SystemClock_Config();
+
+  // Enable basic I/O.
+  P1DIR |= LED_PIN; // LED output.
+  P1REN |= BUTTON_PIN; // Internal resistor enable.
+  P1OUT |= BUTTON_PIN; // Pullup.
+
+  // Enable the backchannel UART (115200)
+  P4DIR |= BIT5;
+  P4SEL |= (BIT5 | BIT4);
+
+  UCA1CTL1 |= (UCSSEL__SMCLK | UCSWRST); // Hold in reset, use SMCLK.
+  UCA1BRW = 4;
+  UCA1MCTL |= (UCBRF_3 | UCBRS_5 | UCOS16); // Overampling mode, 115200 baud.
+                                            // Copied from manual.
+  UCA1CTL1 &= ~UCSWRST;
+
+  // Set up USB pins.
+  USBKEYPID = USBKEY;
+  USBPHYCTL |= PUSEL; // Convert USB D+/D- pins to USB functionality.
+  USBKEYPID = 0;
+}
+
+//--------------------------------------------------------------------+
+// Board porting API
+//--------------------------------------------------------------------+
+
+void board_led_write(bool state)
+{
+  if(state)
+  {
+    LED_PORT |= LED_PIN;
+  }
+  else
+  {
+    LED_PORT &= ~LED_PIN;
+  }
+}
+
+uint32_t board_button_read(void)
+{
+  return ((P1IN & BIT1) >> 1) == BUTTON_STATE_ACTIVE;
+}
+
+int board_uart_read(uint8_t * buf, int len)
+{
+  for(int i = 0; i < len; i++)
+  {
+    // Wait until something to receive (cleared by reading buffer).
+    while(!(UCA1IFG & UCRXIFG));
+    buf[i] = UCA1RXBUF;
+  }
+
+  return len;
+}
+
+int board_uart_write(void const * buf, int len)
+{
+  const char * char_buf = (const char *) buf;
+
+  for(int i = 0; i < len; i++)
+  {
+    // Wait until TX buffer is empty (cleared by writing buffer).
+    while(!(UCA1IFG & UCTXIFG));
+    UCA1TXBUF = char_buf[i];
+  }
+
+  return len;
+}
+
+#if CFG_TUSB_OS  == OPT_OS_NONE
+volatile uint32_t system_ticks = 0;
+void __attribute__ ((interrupt(TIMER0_A0_VECTOR))) TIMER0_A0_ISR (void)
+{
+  system_ticks++;
+  // TAxCCR0 CCIFG resets itself as soon as interrupt is invoked.
+}
+
+uint32_t board_millis(void)
+{
+  uint32_t systick_mirror;
+
+  // 32-bit update is not atomic on MSP430. We can read the bottom 16-bits,
+  // an interrupt occurs, updates _all_ 32 bits, and then we return a
+  // garbage value. And I've seen it happen!
+  TA0CCTL0 &= ~CCIE;
+  systick_mirror = system_ticks;
+  TA0CCTL0 |= CCIE;
+
+  return systick_mirror;
+}
+#endif
diff --git a/src/device/usbd.c b/src/device/usbd.c
index 335c68e8e..ddd99d7f1 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -44,6 +44,7 @@ typedef struct {
   struct TU_ATTR_PACKED
   {
     volatile uint8_t connected    : 1;
+    volatile uint8_t addressed    : 1;
     volatile uint8_t configured   : 1;
     volatile uint8_t suspended    : 1;
 
@@ -526,6 +527,7 @@ static bool process_control_request(uint8_t rhport, tusb_control_request_t const
           usbd_control_set_request(p_request); // set request since DCD has no access to tud_control_status() API
           dcd_set_address(rhport, (uint8_t) p_request->wValue);
           // skip tud_control_status()
+          _usbd_dev.addressed = 1;
         break;
 
         case TUSB_REQ_GET_CONFIGURATION:
@@ -793,7 +795,21 @@ static bool process_get_descriptor(uint8_t rhport, tusb_control_request_t const
   switch(desc_type)
   {
     case TUSB_DESC_DEVICE:
-      return tud_control_xfer(rhport, p_request, (void*) tud_descriptor_device_cb(), sizeof(tusb_desc_device_t));
+    {
+      uint16_t len = sizeof(tusb_desc_device_t);
+
+      // Only send up to EP0 Packet Size if not addressed
+      // This only happens with the very first get device descriptor and EP0 size = 8 or 16.
+      if ((CFG_TUD_ENDPOINT0_SIZE < sizeof(tusb_desc_device_t)) && !_usbd_dev.addressed)
+      {
+        len = CFG_TUD_ENDPOINT0_SIZE;
+
+        // Hack here: we modify the request length to prevent usbd_control response with zlp
+        ((tusb_control_request_t*) p_request)->wLength = CFG_TUD_ENDPOINT0_SIZE;
+      }
+
+      return tud_control_xfer(rhport, p_request, (void*) tud_descriptor_device_cb(), len);
+    }
     break;
 
     case TUSB_DESC_BOS:
@@ -859,6 +875,7 @@ void dcd_event_handler(dcd_event_t const * event, bool in_isr)
   {
     case DCD_EVENT_UNPLUGGED:
       _usbd_dev.connected  = 0;
+      _usbd_dev.addressed  = 0;
       _usbd_dev.configured = 0;
       _usbd_dev.suspended  = 0;
       osal_queue_send(_usbd_q, event, in_isr);
diff --git a/src/device/usbd_control.c b/src/device/usbd_control.c
index 7c35fe768..4fd40c440 100644
--- a/src/device/usbd_control.c
+++ b/src/device/usbd_control.c
@@ -1,4 +1,4 @@
-/* 
+/*
  * The MIT License (MIT)
  *
  * Copyright (c) 2019 Ha Thach (tinyusb.org)
diff --git a/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c b/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c
new file mode 100644
index 000000000..d50fa17fe
--- /dev/null
+++ b/src/portable/ti/msp430x5xx/dcd_msp430x5xx.c
@@ -0,0 +1,626 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019-2020 William D. Jones
+ * Copyright (c) 2019-2020 Ha Thach (tinyusb.org)
+ *
+ * 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.
+ *
+ * This file is part of the TinyUSB stack.
+ */
+
+#include "tusb_option.h"
+
+#if TUSB_OPT_DEVICE_ENABLED && ( CFG_TUSB_MCU == OPT_MCU_MSP430x5xx )
+
+#include "msp430.h"
+#include "device/dcd.h"
+
+/*------------------------------------------------------------------*/
+/* MACRO TYPEDEF CONSTANT ENUM
+ *------------------------------------------------------------------*/
+// usbpllir_mirror and usbmaintl_mirror can be added later if needed.
+static volatile uint16_t usbiepie_mirror = 0;
+static volatile uint16_t usboepie_mirror = 0;
+static volatile uint8_t usbie_mirror = 0;
+static volatile uint16_t usbpwrctl_mirror = 0;
+static bool in_isr = false;
+
+uint8_t _setup_packet[8];
+
+// Xfer control
+typedef struct
+{
+  uint8_t * buffer;
+  uint16_t total_len;
+  uint16_t queued_len;
+  uint16_t max_size;
+  bool short_packet;
+} xfer_ctl_t;
+
+xfer_ctl_t xfer_status[8][2];
+#define XFER_CTL_BASE(_ep, _dir) &xfer_status[_ep][_dir]
+
+// Accessing endpoint regs
+typedef volatile uint8_t * ep_regs_t;
+
+typedef enum
+{
+  CNF = 0,
+  BBAX = 1,
+  BCTX = 2,
+  BBAY = 5,
+  BCTY = 6,
+  SIZXY = 7
+} ep_regs_index_t;
+
+#define EP_REGS(epnum, dir) &USBOEPCNF_1 + 64*dir + 8*(epnum - 1)
+
+
+static void bus_reset(void)
+{
+  // Hardcoded into the USB core.
+  xfer_status[0][TUSB_DIR_OUT].max_size = 8;
+  xfer_status[0][TUSB_DIR_IN].max_size = 8;
+
+  USBKEYPID = USBKEY;
+
+  // Enable the control EP 0. Also enable Indication Enable- a guard flag
+  // separate from the Interrupt Enable mask.
+  USBOEPCNF_0 |= (UBME | USBIIE);
+  USBIEPCNF_0 |= (UBME | USBIIE);
+
+  // Enable interrupts for this endpoint.
+  USBOEPIE |= BIT0;
+  USBIEPIE |= BIT0;
+
+  // Clear NAK until a setup packet is received.
+  USBOEPCNT_0 &= ~NAK;
+  USBIEPCNT_0 &= ~NAK;
+
+  USBCTL |= FEN; // Enable responding to packets.
+
+  // Dedicated buffers in hardware for SETUP and EP0, no setup needed.
+  // Now safe to respond to SETUP packets.
+  USBIE |= SETUPIE;
+
+  USBKEYPID = 0;
+}
+
+
+/*------------------------------------------------------------------*/
+/* Controller API
+ *------------------------------------------------------------------*/
+void dcd_init (uint8_t rhport)
+{
+  (void) rhport;
+
+  USBKEYPID = USBKEY;
+
+  // Enable the module (required to write config regs)!
+  USBCNF |= USB_EN;
+
+  // Reset used interrupts
+  USBOEPIE = 0;
+  USBIEPIE = 0;
+  USBIE = 0;
+  USBOEPIFG = 0;
+  USBIEPIFG = 0;
+  USBIFG = 0;
+  USBPWRCTL &= ~(VUOVLIE | VBONIE | VBOFFIE | VUOVLIFG | VBONIFG | VBOFFIFG);
+  usboepie_mirror = 0;
+  usbiepie_mirror = 0;
+  usbie_mirror = 0;
+  usbpwrctl_mirror = 0;
+
+  USBVECINT = 0;
+
+  // Enable reset and wait for it before continuing.
+  USBIE |= RSTRIE;
+
+  // Enable pullup.
+  USBCNF |= PUR_EN;
+
+  USBKEYPID = 0;
+}
+
+// There is no "USB peripheral interrupt disable" bit on MSP430, so we have
+// to save the relevant registers individually.
+// WARNING: Unlike the ARM/NVIC routines, these functions are _not_ idempotent
+// if you modified the registers saved in between calls so they don't match
+// the mirrors; mirrors will be updated to reflect most recent register
+// contents.
+void dcd_int_enable (uint8_t rhport)
+{
+  (void) rhport;
+
+  __bic_SR_register(GIE); // Unlikely to be called in ISR, but let's be safe.
+                          // Also, this cleanly disables all USB interrupts
+                          // atomically from application's POV.
+
+  // This guard is required because tinyusb can enable interrupts without
+  // having disabled them first.
+  if(in_isr)
+  {
+    USBOEPIE = usboepie_mirror;
+    USBIEPIE = usbiepie_mirror;
+    USBIE = usbie_mirror;
+    USBPWRCTL |= usbpwrctl_mirror;
+  }
+
+  in_isr = false;
+  __bis_SR_register(GIE);
+}
+
+void dcd_int_disable (uint8_t rhport)
+{
+  (void) rhport;
+
+  __bic_SR_register(GIE);
+  usboepie_mirror = USBOEPIE;
+  usbiepie_mirror = USBIEPIE;
+  usbie_mirror = USBIE;
+  usbpwrctl_mirror = (USBPWRCTL & (VUOVLIE | VBONIE | VBOFFIE));
+  USBOEPIE = 0;
+  USBIEPIE = 0;
+  USBIE = 0;
+  USBPWRCTL &= ~(VUOVLIE | VBONIE | VBOFFIE);
+  in_isr = true;
+  __bis_SR_register(GIE);
+}
+
+void dcd_set_address (uint8_t rhport, uint8_t dev_addr)
+{
+  (void) rhport;
+
+  USBFUNADR = dev_addr;
+
+  // Response with status after changing device address
+  dcd_edpt_xfer(rhport, tu_edpt_addr(0, TUSB_DIR_IN), NULL, 0);
+}
+
+void dcd_set_config (uint8_t rhport, uint8_t config_num)
+{
+  (void) rhport;
+  (void) config_num;
+  // Nothing to do
+}
+
+void dcd_remote_wakeup(uint8_t rhport)
+{
+  (void) rhport;
+}
+
+/*------------------------------------------------------------------*/
+/* DCD Endpoint port
+ *------------------------------------------------------------------*/
+
+bool dcd_edpt_open (uint8_t rhport, tusb_desc_endpoint_t const * desc_edpt)
+{
+  (void) rhport;
+
+  uint8_t const epnum = tu_edpt_number(desc_edpt->bEndpointAddress);
+  uint8_t const dir   = tu_edpt_dir(desc_edpt->bEndpointAddress);
+
+  // Unsupported endpoint numbers/size or type (Iso not supported. Control
+  // not supported on nonzero endpoints).
+  if((desc_edpt->wMaxPacketSize.size > 64) || (epnum > 7) || \
+      (desc_edpt->bmAttributes.xfer == 0) || \
+      (desc_edpt->bmAttributes.xfer == 1)) {
+    return false;
+  }
+
+  xfer_ctl_t * xfer = XFER_CTL_BASE(epnum, dir);
+  xfer->max_size = desc_edpt->wMaxPacketSize.size;
+
+  // Buffer allocation scheme:
+  // For simplicity, only single buffer for now, since tinyusb currently waits
+  // for an xfer to complete before scheduling another one. This means only
+  // the X buffer is used.
+  //
+  // 1904 bytes are available, the max endpoint size supported on msp430 is
+  // 64 bytes. This is enough RAM for all 14 endpoints enabled _with_ double
+  // bufferring (64*14*2 = 1792 bytes). Extra RAM exists for triple and higher
+  // order bufferring, which must be maintained in software.
+  //
+  // For simplicity, each endpoint gets a hardcoded 64 byte chunk (regardless
+  // of actual wMaxPacketSize) whose start address is the following:
+  // addr = 128 * (epnum - 1) + 64 * dir.
+  //
+  // Double buffering equation:
+  // x_addr = 256 * (epnum - 1) + 128 * dir
+  // y_addr = x_addr + 64
+  // Address is right-shifted by 3 to fit into 8 bits.
+
+  uint8_t buf_base = (128 * (epnum - 1) + 64 * dir) >> 3;
+
+  // IN and OUT EP registers have the same structure.
+  ep_regs_t ep_regs = EP_REGS(epnum, dir);
+
+  // FIXME: I was able to get into a situation where OUT EP 3 would stall
+  // while debugging, despite stall code never being called. It appears
+  // these registers don't get cleared on reset, being part of RAM.
+  // Investigate and see if I can duplicate.
+  // Also, DBUF got set on OUT EP 2 while debugging. Only OUT EPs seem to be
+  // affected at this time. USB RAM directly precedes main RAM; perhaps I'm
+  // overwriting registers via buffer overflow w/ my debugging code?
+  ep_regs[SIZXY] = desc_edpt->wMaxPacketSize.size;
+  ep_regs[BCTX] |= NAK;
+  ep_regs[BBAX] = buf_base;
+  ep_regs[CNF] &= ~(TOGGLE | STALL | DBUF); // ISO xfers not supported on
+                           // MSP430, so no need to gate DATA0/1 and frame
+                           // behavior. Clear stall and double buffer bit as
+                           // well- see above comment.
+  ep_regs[CNF] |= (UBME | USBIIE);
+
+  USBKEYPID = USBKEY;
+  if(dir == TUSB_DIR_OUT)
+  {
+    USBOEPIE |= (1 << epnum);
+  }
+  else
+  {
+    USBIEPIE |= (1 << epnum);
+  }
+  USBKEYPID = 0;
+
+  return true;
+}
+
+bool dcd_edpt_xfer (uint8_t rhport, uint8_t ep_addr, uint8_t * buffer, uint16_t total_bytes)
+{
+  (void) rhport;
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir   = tu_edpt_dir(ep_addr);
+
+  xfer_ctl_t * xfer = XFER_CTL_BASE(epnum, dir);
+  xfer->buffer = buffer;
+  xfer->total_len = total_bytes;
+  xfer->queued_len = 0;
+  xfer->short_packet = false;
+
+  if(epnum == 0)
+  {
+    if(dir == TUSB_DIR_OUT)
+    {
+      // Interrupt will notify us when data was received.
+      USBCTL &= ~DIR;
+      USBOEPCNT_0 &= ~NAK;
+    }
+    else
+    {
+      // Kickstart the IN packet handler by queuing initial data and calling
+      // the ISR to transmit the first packet.
+      // Interrupt only fires on completed xfer.
+      USBCTL |= DIR;
+      USBIEPIFG |= BIT0;
+    }
+  }
+  else
+  {
+    ep_regs_t ep_regs = EP_REGS(epnum, dir);
+
+    if(dir == TUSB_DIR_OUT)
+    {
+      ep_regs[BCTX] &= ~NAK;
+    }
+    else
+    {
+      USBIEPIFG |= (1 << epnum);
+    }
+  }
+
+  return true;
+}
+
+void dcd_edpt_stall (uint8_t rhport, uint8_t ep_addr)
+{
+  (void) rhport;
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir   = tu_edpt_dir(ep_addr);
+
+  if(epnum == 0)
+  {
+    if(dir == TUSB_DIR_OUT)
+    {
+      USBOEPCNT_0 |= NAK;
+      USBOEPCNF_0 |= STALL;
+    }
+    else
+    {
+      USBIEPCNT_0 |= NAK;
+      USBIEPCNF_0 |= STALL;
+    }
+  }
+  else
+  {
+    ep_regs_t ep_regs = EP_REGS(epnum, dir);
+    ep_regs[CNF] |= STALL;
+  }
+}
+
+void dcd_edpt_clear_stall (uint8_t rhport, uint8_t ep_addr)
+{
+  (void) rhport;
+
+  uint8_t const epnum = tu_edpt_number(ep_addr);
+  uint8_t const dir   = tu_edpt_dir(ep_addr);
+
+  if(epnum == 0)
+  {
+    if(dir == TUSB_DIR_OUT)
+    {
+      USBOEPCNF_0 &= ~STALL;
+    }
+    else
+    {
+      USBIEPCNF_0 &= ~STALL;
+    }
+  }
+  else
+  {
+    ep_regs_t ep_regs = EP_REGS(epnum, dir);
+    // Required by USB spec to reset DATA toggle bit to DATA0 on interrupt
+    // and bulk endpoints.
+    ep_regs[CNF] &= ~(STALL + TOGGLE);
+  }
+}
+
+void dcd_edpt0_status_complete(uint8_t rhport, tusb_control_request_t const * request)
+{
+  (void) rhport;
+  (void) request;
+
+  // FIXME: Per manual, we should be clearing the NAK bits of EP0 after the
+  // Status Phase of a control xfer is done, in preparation of another possible
+  // SETUP packet. However, from my own testing, SETUP packets _are_ correctly
+  // handled by the USB core without clearing the NAKs.
+  //
+  // Right now, clearing NAKs in this callbacks causes a direction mismatch
+  // between host and device on EP0. Figure out why and come back to this.
+  // USBOEPCNT_0 &= ~NAK;
+  // USBIEPCNT_0 &= ~NAK;
+}
+
+/*------------------------------------------------------------------*/
+
+static void receive_packet(uint8_t ep_num)
+{
+  xfer_ctl_t * xfer = XFER_CTL_BASE(ep_num, TUSB_DIR_OUT);
+  ep_regs_t ep_regs = EP_REGS(ep_num, TUSB_DIR_OUT);
+  uint8_t xfer_size;
+
+  if(ep_num == 0)
+  {
+    xfer_size = USBOEPCNT_0 & 0x0F;
+  }
+  else
+  {
+    xfer_size = ep_regs[BCTX] & 0x7F;
+  }
+
+  uint16_t remaining = xfer->total_len - xfer->queued_len;
+  uint16_t to_recv_size;
+
+  if(remaining <= xfer->max_size) {
+    // Avoid buffer overflow.
+    to_recv_size = (xfer_size > remaining) ? remaining : xfer_size;
+  } else {
+    // Room for full packet, choose recv_size based on what the microcontroller
+    // claims.
+    to_recv_size = (xfer_size > xfer->max_size) ? xfer->max_size : xfer_size;
+  }
+
+  uint8_t * base = (xfer->buffer + xfer->queued_len);
+
+  if(ep_num == 0)
+  {
+    volatile uint8_t * ep0out_buf = &USBOEP0BUF;
+    for(uint16_t i = 0; i < to_recv_size; i++)
+    {
+      base[i] = ep0out_buf[i];
+    }
+  }
+  else
+  {
+    volatile uint8_t * ep_buf = &USBSTABUFF + (ep_regs[BBAX] << 3);
+    for(uint16_t i = 0; i < to_recv_size ; i++)
+    {
+      base[i] = ep_buf[i];
+    }
+  }
+
+  xfer->queued_len += xfer_size;
+
+  xfer->short_packet = (xfer_size < xfer->max_size);
+  if((xfer->total_len == xfer->queued_len) || xfer->short_packet)
+  {
+    dcd_event_xfer_complete(0, ep_num, xfer->queued_len, XFER_RESULT_SUCCESS, true);
+  }
+  else
+  {
+    // Schedule to receive another packet.
+    if(ep_num == 0)
+    {
+      USBOEPCNT_0 &= ~NAK;
+    }
+    else
+    {
+      ep_regs[BCTX] &= ~NAK;
+    }
+  }
+}
+
+static void transmit_packet(uint8_t ep_num)
+{
+  xfer_ctl_t * xfer = XFER_CTL_BASE(ep_num, TUSB_DIR_IN);
+
+  // First, determine whether we should even send a packet or finish
+  // up the xfer.
+  bool zlp = (xfer->total_len == 0); // By necessity, xfer->total_len will
+                                     // equal xfer->queued_len for ZLPs.
+                                     // Of course a ZLP is a short packet.
+  if((!zlp && (xfer->total_len == xfer->queued_len)) || xfer->short_packet)
+  {
+    dcd_event_xfer_complete(0, ep_num | TUSB_DIR_IN_MASK, xfer->queued_len, XFER_RESULT_SUCCESS, true);
+    return;
+  }
+
+  // Then actually commit to transmit a packet.
+  uint8_t * base = (xfer->buffer + xfer->queued_len);
+  uint16_t remaining = xfer->total_len - xfer->queued_len;
+  uint8_t xfer_size = (xfer->max_size < xfer->total_len) ? xfer->max_size : remaining;
+
+  xfer->queued_len += xfer_size;
+  if(xfer_size < xfer->max_size)
+  {
+    // Next "xfer complete interrupt", the transfer will end.
+    xfer->short_packet = true;
+  }
+
+  if(ep_num == 0)
+  {
+    volatile uint8_t * ep0in_buf = &USBIEP0BUF;
+    for(uint16_t i = 0; i < xfer_size; i++)
+    {
+      ep0in_buf[i] = base[i];
+    }
+
+    USBIEPCNT_0 = (USBIEPCNT_0 & 0xF0) + xfer_size;
+    USBIEPCNT_0 &= ~NAK;
+  }
+  else
+  {
+    ep_regs_t ep_regs = EP_REGS(ep_num, TUSB_DIR_IN);
+    volatile uint8_t * ep_buf = &USBSTABUFF + (ep_regs[BBAX] << 3);
+
+    for(int i = 0; i < xfer_size; i++)
+    {
+      ep_buf[i] = base[i];
+    }
+
+    ep_regs[BCTX] = (ep_regs[BCTX] & 0x80) + (xfer_size & 0x7F);
+    ep_regs[BCTX] &= ~NAK;
+  }
+}
+
+static void handle_setup_packet(void)
+{
+  volatile uint8_t * setup_buf = &USBSUBLK;
+
+  for(int i = 0; i < 8; i++)
+  {
+    _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.
+  USBIEPCNT_0 |= NAK;
+  USBOEPCNT_0 |= NAK;
+  dcd_event_setup_received(0, (uint8_t*) &_setup_packet[0], true);
+}
+
+void __attribute__ ((interrupt(USB_UBM_VECTOR))) USB_UBM_ISR(void)
+{
+  // Setup is special- reading USBVECINT to handle setup packets is done to
+  // stop hardware-generated NAKs on EP0.
+  uint8_t setup_status = USBIFG & SETUPIFG;
+
+  if(setup_status)
+  {
+    handle_setup_packet();
+  }
+
+  uint16_t curr_vector = USBVECINT;
+
+  switch(curr_vector)
+  {
+    case USBVECINT_RSTR:
+      bus_reset();
+      dcd_event_bus_signal(0, DCD_EVENT_BUS_RESET, 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
+    // sending/receiving data before tinyusb is ready.
+    //
+    // Furthermore, it's possible for the hardware to STALL in the middle of
+    // a control xfer if the EP0 NAK bits aren't set properly.
+    // See: https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/845259
+    // From my testing, if all of the following hold:
+    // * OUT EP0 NAK is cleared.
+    // * IN EP0 NAK is set.
+    // * DIR bit in USBCTL is clear.
+    // and an IN packet is received on EP0, the USB core will STALL. Setting
+    // both EP0 NAKs manually when a SETUP packet is received, as is done
+    // in handle_setup_packet(), avoids meeting STALL conditions.
+    //
+    // TODO: Figure out/explain why the STALL condition can be reached in the
+    // first place. When I first noticed the STALL, the only two places I
+    // touched the NAK bits were in dcd_edpt_xfer() and to _set_ (sic) them in
+    // bus_reset(). SETUP packet handling should've been unaffected.
+    case USBVECINT_SETUP_PACKET_RECEIVED:
+      break;
+
+    case USBVECINT_INPUT_ENDPOINT0:
+      transmit_packet(0);
+      break;
+
+    case USBVECINT_OUTPUT_ENDPOINT0:
+      receive_packet(0);
+      break;
+
+    case USBVECINT_INPUT_ENDPOINT1:
+    case USBVECINT_INPUT_ENDPOINT2:
+    case USBVECINT_INPUT_ENDPOINT3:
+    case USBVECINT_INPUT_ENDPOINT4:
+    case USBVECINT_INPUT_ENDPOINT5:
+    case USBVECINT_INPUT_ENDPOINT6:
+    case USBVECINT_INPUT_ENDPOINT7:
+    {
+      uint8_t ep = ((curr_vector - USBVECINT_INPUT_ENDPOINT1) >> 1) + 1;
+      transmit_packet(ep);
+    }
+    break;
+
+    case USBVECINT_OUTPUT_ENDPOINT1:
+    case USBVECINT_OUTPUT_ENDPOINT2:
+    case USBVECINT_OUTPUT_ENDPOINT3:
+    case USBVECINT_OUTPUT_ENDPOINT4:
+    case USBVECINT_OUTPUT_ENDPOINT5:
+    case USBVECINT_OUTPUT_ENDPOINT6:
+    case USBVECINT_OUTPUT_ENDPOINT7:
+    {
+      uint8_t ep = ((curr_vector - USBVECINT_OUTPUT_ENDPOINT1) >> 1) + 1;
+      receive_packet(ep);
+    }
+    break;
+
+    default:
+      while(true);
+      break;
+  }
+
+}
+
+#endif
diff --git a/src/tusb.c b/src/tusb.c
index 5dc6825d7..8e0022f4d 100644
--- a/src/tusb.c
+++ b/src/tusb.c
@@ -71,7 +71,7 @@ char const* const tusb_strerr[TUSB_ERROR_COUNT] = { ERROR_TABLE(ERROR_STRING) };
 static void dump_str_line(uint8_t const* buf, uint16_t count)
 {
   // each line is 16 bytes
-  for(int i=0; i<count; i++)
+  for(uint16_t i=0; i<count; i++)
   {
     const char ch = buf[i];
     tu_printf("%c", isprint(ch) ? ch : '.');
@@ -131,7 +131,7 @@ void tu_print_mem(void const *buf, uint16_t count, uint8_t indent)
 
   if ( remain )
   {
-    for(int i=0; i< 16-remain; i++)
+    for(uint16_t i=0; i< 16-remain; i++)
     {
       tu_printf(" ");
       for(int j=0; j<2*size; j++) tu_printf(" ");
diff --git a/src/tusb_option.h b/src/tusb_option.h
index 0ae049f7e..4a9d05712 100644
--- a/src/tusb_option.h
+++ b/src/tusb_option.h
@@ -71,8 +71,12 @@
 #define OPT_MCU_STM32L1           308 ///< ST STM32L1
 #define OPT_MCU_STM32L4           309 ///< ST STM32L4
 
+// Sony
 #define OPT_MCU_CXD56             400 ///< SONY CXD56
 
+// TI MSP430
+#define OPT_MCU_MSP430x5xx    500 ///< TI MSP430x5xx
+
 #define OPT_MCU_VALENTYUSB_EPTRI  600 ///< Fomu eptri config
 
 #define OPT_MCU_MIMXRT10XX        700 ///< NXP iMX RT10xx