diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..e0beb50
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "stm32/aioc-fw/Middlewares/Third-Party/tinyusb"]
+	path = stm32/aioc-fw/Middlewares/Third-Party/tinyusb
+	url = https://github.com/hathach/tinyusb.git
diff --git a/stm32/aioc-fw/.cproject b/stm32/aioc-fw/.cproject
index f8c708e..fb669ca 100644
--- a/stm32/aioc-fw/.cproject
+++ b/stm32/aioc-fw/.cproject
@@ -41,6 +41,7 @@
 							<tool id="com.atollic.truestudio.exe.debug.toolchain.gcc.851313840" name="C Compiler" superClass="com.atollic.truestudio.exe.debug.toolchain.gcc">
 								<option id="com.atollic.truestudio.gcc.symbols.defined.1891788809" name="Defined symbols" superClass="com.atollic.truestudio.gcc.symbols.defined" useByScannerDiscovery="false" valueType="definedSymbols">
 									<listOptionValue builtIn="false" value="STM32F302xC"/>
+									<listOptionValue builtIn="false" value="CFG_TUSB_MCU=OPT_MCU_STM32F3"/>
 								</option>
 								<option id="com.atollic.truestudio.gcc.directories.select.354352931" name="Include path" superClass="com.atollic.truestudio.gcc.directories.select" useByScannerDiscovery="false" valueType="includePath">
 									<listOptionValue builtIn="false" value="../Drivers/CMSIS/Include"/>
@@ -48,6 +49,7 @@
 									<listOptionValue builtIn="false" value="../Drivers/STM32F3xx_HAL_Driver/Inc"/>
 									<listOptionValue builtIn="false" value="../Src"/>
 									<listOptionValue builtIn="false" value="../Inc"/>
+									<listOptionValue builtIn="false" value="../Middlewares/Third-Party/tinyusb/src"/>
 								</option>
 								<option id="com.atollic.truestudio.common_options.target.endianess.1746744356" name="Endianess" superClass="com.atollic.truestudio.common_options.target.endianess" useByScannerDiscovery="false"/>
 								<option id="com.atollic.truestudio.common_options.target.mcpu.706240371" name="Microcontroller" superClass="com.atollic.truestudio.common_options.target.mcpu" useByScannerDiscovery="false" value="STM32F302CB" valueType="enumerated"/>
@@ -107,6 +109,8 @@
 					</folderInfo>
 					<sourceEntries>
 						<entry excluding="STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_timebase_tim_template.c|STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_timebase_rtc_wakeup_template.c|STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_msp_template.c|STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_timebase_rtc_alarm_template.c|CMSIS/Device/ST/STM32F3xx/Source" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Drivers"/>
+						<entry flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Inc"/>
+						<entry flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="Middlewares/Third-Party/tinyusb/src"/>
 						<entry flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Src"/>
 					</sourceEntries>
 				</configuration>
@@ -153,6 +157,7 @@
 							<tool id="com.atollic.truestudio.exe.release.toolchain.gcc.1961490706" name="C Compiler" superClass="com.atollic.truestudio.exe.release.toolchain.gcc">
 								<option id="com.atollic.truestudio.gcc.symbols.defined.588533484" name="Defined symbols" superClass="com.atollic.truestudio.gcc.symbols.defined" useByScannerDiscovery="false" valueType="definedSymbols">
 									<listOptionValue builtIn="false" value="STM32F302xC"/>
+									<listOptionValue builtIn="false" value="CFG_TUSB_MCU=OPT_MCU_STM32F3"/>
 								</option>
 								<option id="com.atollic.truestudio.gcc.directories.select.504368704" name="Include path" superClass="com.atollic.truestudio.gcc.directories.select" useByScannerDiscovery="false" valueType="includePath">
 									<listOptionValue builtIn="false" value="../Drivers/CMSIS/Include"/>
@@ -160,6 +165,7 @@
 									<listOptionValue builtIn="false" value="../Drivers/STM32F3xx_HAL_Driver/Inc"/>
 									<listOptionValue builtIn="false" value="../Src"/>
 									<listOptionValue builtIn="false" value="../Inc"/>
+									<listOptionValue builtIn="false" value="../Middlewares/Third-Party/tinyusb/src"/>
 								</option>
 								<option id="com.atollic.truestudio.common_options.target.endianess.2026048991" name="Endianess" superClass="com.atollic.truestudio.common_options.target.endianess" useByScannerDiscovery="false"/>
 								<option id="com.atollic.truestudio.common_options.target.mcpu.410573286" name="Microcontroller" superClass="com.atollic.truestudio.common_options.target.mcpu" useByScannerDiscovery="false" value="STM32F302CB" valueType="enumerated"/>
@@ -219,6 +225,8 @@
 					</folderInfo>
 					<sourceEntries>
 						<entry excluding="STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_timebase_tim_template.c|STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_timebase_rtc_wakeup_template.c|STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_msp_template.c|STM32F3xx_HAL_Driver/Src/stm32f3xx_hal_timebase_rtc_alarm_template.c|CMSIS/Device/ST/STM32F3xx/Source" flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Drivers"/>
+						<entry flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="Inc"/>
+						<entry flags="VALUE_WORKSPACE_PATH" kind="sourcePath" name="Middlewares/Third-Party/tinyusb/src"/>
 						<entry flags="VALUE_WORKSPACE_PATH|RESOLVED" kind="sourcePath" name="Src"/>
 					</sourceEntries>
 				</configuration>
diff --git a/stm32/aioc-fw/Inc/tusb_config.h b/stm32/aioc-fw/Inc/tusb_config.h
new file mode 100644
index 0000000..070f08e
--- /dev/null
+++ b/stm32/aioc-fw/Inc/tusb_config.h
@@ -0,0 +1,111 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef _TUSB_CONFIG_H_
+#define _TUSB_CONFIG_H_
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+//--------------------------------------------------------------------+
+// Board Specific Configuration
+//--------------------------------------------------------------------+
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_TUD_RHPORT
+#define BOARD_TUD_RHPORT      0
+#endif
+
+// RHPort max operational speed can defined by board.mk
+#ifndef BOARD_TUD_MAX_SPEED
+#define BOARD_TUD_MAX_SPEED   OPT_MODE_DEFAULT_SPEED
+#endif
+
+//--------------------------------------------------------------------
+// COMMON CONFIGURATION
+//--------------------------------------------------------------------
+
+// defined by board.mk
+#ifndef CFG_TUSB_MCU
+#error CFG_TUSB_MCU must be defined
+#endif
+
+#ifndef CFG_TUSB_OS
+#define CFG_TUSB_OS           OPT_OS_NONE
+#endif
+
+#ifndef CFG_TUSB_DEBUG
+#define CFG_TUSB_DEBUG        0
+#endif
+
+// Enable Device stack
+#define CFG_TUD_ENABLED       1
+
+// Default is max speed that hardware controller could support with on-chip PHY
+#define CFG_TUD_MAX_SPEED     BOARD_TUD_MAX_SPEED
+
+/* USB DMA on some MCUs can only access a specific SRAM region with restriction on alignment.
+ * Tinyusb use follows macros to declare transferring memory so that they can be put
+ * into those specific section.
+ * e.g
+ * - CFG_TUSB_MEM SECTION : __attribute__ (( section(".usb_ram") ))
+ * - CFG_TUSB_MEM_ALIGN   : __attribute__ ((aligned(4)))
+ */
+#ifndef CFG_TUSB_MEM_SECTION
+#define CFG_TUSB_MEM_SECTION
+#endif
+
+#ifndef CFG_TUSB_MEM_ALIGN
+#define CFG_TUSB_MEM_ALIGN          __attribute__ ((aligned(4)))
+#endif
+
+//--------------------------------------------------------------------
+// DEVICE CONFIGURATION
+//--------------------------------------------------------------------
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+#define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
+
+//------------- CLASS -------------//
+#define CFG_TUD_CDC               2
+#define CFG_TUD_MSC               0
+#define CFG_TUD_HID               0
+#define CFG_TUD_MIDI              0
+#define CFG_TUD_VENDOR            0
+
+// CDC FIFO size of TX and RX
+#define CFG_TUD_CDC_RX_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+#define CFG_TUD_CDC_TX_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+
+// CDC Endpoint transfer buffer size, more is faster
+#define CFG_TUD_CDC_EP_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/stm32/aioc-fw/Middlewares/Third-Party/tinyusb b/stm32/aioc-fw/Middlewares/Third-Party/tinyusb
new file mode 160000
index 0000000..9e91b02
--- /dev/null
+++ b/stm32/aioc-fw/Middlewares/Third-Party/tinyusb
@@ -0,0 +1 @@
+Subproject commit 9e91b02ec7fb3502747b5c413a4824654fa7fc7e
diff --git a/stm32/aioc-fw/Src/main.c b/stm32/aioc-fw/Src/main.c
index 5f432ea..3c05bd2 100644
--- a/stm32/aioc-fw/Src/main.c
+++ b/stm32/aioc-fw/Src/main.c
@@ -4,6 +4,7 @@
 #include "stm32f3xx_hal_rcc_ex.h"
 #include "stm32f3xx_hal_gpio.h"
 #include "stm32f3xx_hal_tim.h"
+#include "tusb.h"
 
 static void SystemClock_Config(void)
 {
@@ -60,7 +61,7 @@ static void SystemClock_Config(void)
 }
 
 #define LED1_SET(x) TIM4->CCR3 = ( ((uint32_t) ((x) * 255)) & 0xFF )
-#define LED2_SET(x) TIM4->CCR4 = (511 - ( ((uint32_t) ((x) * 255)) & 0xFF ))
+#define LED2_SET(x) TIM4->CCR4 = (512 - ( ((uint32_t) ((x) * 255)) & 0xFF ))
 
 static void LED_Init(void)
 {
@@ -89,11 +90,104 @@ static void LED_Init(void)
 	TIM4->CCMR2 =  TIM_OCMODE_PWM1 << 8 | TIM_OCMODE_PWM1 | TIM_CCMR2_OC3PE | TIM_CCMR2_OC4PE;
 	TIM4->CCER = (0 << TIM_CCER_CC3P_Pos) | (1 << TIM_CCER_CC4P_Pos) | TIM_CCER_CC3E | TIM_CCER_CC4E;
 	TIM4->CCR3 = 0;
-	TIM4->CCR4 = 511;
+	TIM4->CCR4 = 512;
 	TIM4->EGR = TIM_EGR_UG;
 	TIM4->CR1 |= TIM_CR1_CEN;
 }
 
+static void USB_Init(void)
+{
+	  __HAL_REMAPINTERRUPT_USB_ENABLE();
+
+	  /* Configure USB DM and DP pins */
+	  __HAL_RCC_GPIOA_CLK_ENABLE();
+	  GPIO_InitTypeDef GPIO_InitStruct;
+	  GPIO_InitStruct.Pin = (GPIO_PIN_11 | GPIO_PIN_12);
+	  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
+	  GPIO_InitStruct.Pull = GPIO_NOPULL;
+	  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
+	  GPIO_InitStruct.Alternate = GPIO_AF14_USB;
+	  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
+
+	  // Enable USB clock
+	  __HAL_RCC_USB_CLK_ENABLE();
+}
+
+
+// echo to either Serial0 or Serial1
+// with Serial0 as all lower case, Serial1 as all upper case
+static void echo_serial_port(uint8_t itf, uint8_t buf[], uint32_t count)
+{
+  uint8_t const case_diff = 'a' - 'A';
+
+  for(uint32_t i=0; i<count; i++)
+  {
+    if (itf == 0)
+    {
+      // echo back 1st port as lower case
+      if (isupper(buf[i])) buf[i] += case_diff;
+    }
+    else
+    {
+      // echo back 2nd port as upper case
+      if (islower(buf[i])) buf[i] -= case_diff;
+    }
+
+    tud_cdc_n_write_char(itf, buf[i]);
+  }
+  tud_cdc_n_write_flush(itf);
+}
+
+//--------------------------------------------------------------------+
+// USB CDC
+//--------------------------------------------------------------------+
+static void cdc_task(void)
+{
+  uint8_t itf;
+
+  for (itf = 0; itf < CFG_TUD_CDC; itf++)
+  {
+    // connected() check for DTR bit
+    // Most but not all terminal client set this when making connection
+    // if ( tud_cdc_n_connected(itf) )
+    {
+      if ( tud_cdc_n_available(itf) )
+      {
+        uint8_t buf[64];
+
+        uint32_t count = tud_cdc_n_read(itf, buf, sizeof(buf));
+
+        // echo back to both serial ports
+        echo_serial_port(0, buf, count);
+        echo_serial_port(1, buf, count);
+      }
+    }
+  }
+}
+
+
+// Invoked when cdc when line state changed e.g connected/disconnected
+void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts)
+{
+  (void) itf;
+  (void) rts;
+
+  // TODO set some indicator
+  if ( dtr )
+  {
+	  LED2_SET(1.0);
+  }else
+  {
+	  LED2_SET(0.0);
+  }
+}
+
+// Invoked when CDC interface received data from host
+void tud_cdc_rx_cb(uint8_t itf)
+{
+  (void) itf;
+  LED1_SET(1.0);
+}
 
 
 int main(void)
@@ -101,24 +195,29 @@ int main(void)
     HAL_Init();
     SystemClock_Config();
 
-    LED_Init();
-
     __HAL_RCC_SYSCFG_CLK_ENABLE();
 
-    LED1_SET(1.0);
-    LED2_SET(1.0);
+    LED_Init();
+
+    USB_Init();
+
+    tud_init(BOARD_TUD_RHPORT);
+
+    LED1_SET(0.0);
+    LED2_SET(0.0);
 
     volatile uint32_t ii = 0;
 
     /* TODO - Add your application code here */
     while (1) {
-        ii++;
-
+        tud_task();
+        cdc_task();
     }
 
   return 0;
 }
 
+
 void NMI_Handler(void) {
 }
 
@@ -158,3 +257,28 @@ void PendSV_Handler(void) {
 void SysTick_Handler(void) {
     HAL_IncTick();
 }
+
+
+// FIXME: Do all three need to be handled, or just the LP one?
+// USB high-priority interrupt (Channel 74): Triggered only by a correct
+// transfer event for isochronous and double-buffer bulk transfer to reach
+// the highest possible transfer rate.
+void USB_HP_IRQHandler(void)
+{
+  tud_int_handler(0);
+}
+
+// USB low-priority interrupt (Channel 75): Triggered by all USB events
+// (Correct transfer, USB reset, etc.). The firmware has to check the
+// interrupt source before serving the interrupt.
+void USB_LP_IRQHandler(void)
+{
+  tud_int_handler(0);
+}
+
+// USB wakeup interrupt (Channel 76): Triggered by the wakeup event from the USB
+// Suspend mode.
+void USBWakeUp_RMP_IRQHandler(void)
+{
+  tud_int_handler(0);
+}
diff --git a/stm32/aioc-fw/Src/usb_descriptors.c b/stm32/aioc-fw/Src/usb_descriptors.c
new file mode 100644
index 0000000..dc62c00
--- /dev/null
+++ b/stm32/aioc-fw/Src/usb_descriptors.c
@@ -0,0 +1,253 @@
+/*
+ * 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.
+ *
+ */
+
+#include "tusb.h"
+
+/* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
+ * Same VID/PID with different interface e.g MSC (first), then CDC (later) will possibly cause system error on PC.
+ *
+ * Auto ProductID layout's Bitmap:
+ *   [MSB]       MIDI | HID | MSC | CDC          [LSB]
+ */
+#define _PID_MAP(itf, n)  ( (CFG_TUD_##itf) << (n) )
+#define USB_PID           (0x4000 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) | _PID_MAP(HID, 2) | \
+                           _PID_MAP(MIDI, 3) | _PID_MAP(VENDOR, 4) )
+
+#define USB_VID   0xCafe
+#define USB_BCD   0x0200
+
+//--------------------------------------------------------------------+
+// Device Descriptors
+//--------------------------------------------------------------------+
+tusb_desc_device_t const desc_device =
+{
+    .bLength            = sizeof(tusb_desc_device_t),
+    .bDescriptorType    = TUSB_DESC_DEVICE,
+    .bcdUSB             = USB_BCD,
+
+    // Use Interface Association Descriptor (IAD) for CDC
+    // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
+    .bDeviceClass       = TUSB_CLASS_MISC,
+    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+
+    .idVendor           = USB_VID,
+    .idProduct          = USB_PID,
+    .bcdDevice          = 0x0100,
+
+    .iManufacturer      = 0x01,
+    .iProduct           = 0x02,
+    .iSerialNumber      = 0x03,
+
+    .bNumConfigurations = 0x01
+};
+
+// Invoked when received GET DEVICE DESCRIPTOR
+// Application return pointer to descriptor
+uint8_t const * tud_descriptor_device_cb(void)
+{
+  return (uint8_t const *) &desc_device;
+}
+
+//--------------------------------------------------------------------+
+// Configuration Descriptor
+//--------------------------------------------------------------------+
+enum
+{
+  ITF_NUM_CDC_0 = 0,
+  ITF_NUM_CDC_0_DATA,
+  ITF_NUM_CDC_1,
+  ITF_NUM_CDC_1_DATA,
+  ITF_NUM_TOTAL
+};
+
+#define CONFIG_TOTAL_LEN    (TUD_CONFIG_DESC_LEN + CFG_TUD_CDC * TUD_CDC_DESC_LEN)
+
+#if CFG_TUSB_MCU == OPT_MCU_LPC175X_6X || CFG_TUSB_MCU == OPT_MCU_LPC177X_8X || CFG_TUSB_MCU == OPT_MCU_LPC40XX
+  // LPC 17xx and 40xx endpoint type (bulk/interrupt/iso) are fixed by its number
+  // 0 control, 1 In, 2 Bulk, 3 Iso, 4 In etc ...
+  #define EPNUM_CDC_0_NOTIF   0x81
+  #define EPNUM_CDC_0_OUT     0x02
+  #define EPNUM_CDC_0_IN      0x82
+
+  #define EPNUM_CDC_1_NOTIF   0x84
+  #define EPNUM_CDC_1_OUT     0x05
+  #define EPNUM_CDC_1_IN      0x85
+
+#elif CFG_TUSB_MCU == OPT_MCU_SAMG || CFG_TUSB_MCU ==  OPT_MCU_SAMX7X
+  // SAMG & SAME70 don't support a same endpoint number with different direction IN and OUT
+  //    e.g EP1 OUT & EP1 IN cannot exist together
+  #define EPNUM_CDC_0_NOTIF   0x81
+  #define EPNUM_CDC_0_OUT     0x02
+  #define EPNUM_CDC_0_IN      0x83
+
+  #define EPNUM_CDC_1_NOTIF   0x84
+  #define EPNUM_CDC_1_OUT     0x05
+  #define EPNUM_CDC_1_IN      0x86
+
+#else
+  #define EPNUM_CDC_0_NOTIF   0x81
+  #define EPNUM_CDC_0_OUT     0x02
+  #define EPNUM_CDC_0_IN      0x82
+
+  #define EPNUM_CDC_1_NOTIF   0x83
+  #define EPNUM_CDC_1_OUT     0x04
+  #define EPNUM_CDC_1_IN      0x84
+#endif
+
+uint8_t const desc_fs_configuration[] =
+{
+  // Config number, interface count, string index, total length, attribute, power in mA
+  TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+  // 1st CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_0, 4, EPNUM_CDC_0_NOTIF, 8, EPNUM_CDC_0_OUT, EPNUM_CDC_0_IN, 64),
+
+  // 2nd CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_1, 4, EPNUM_CDC_1_NOTIF, 8, EPNUM_CDC_1_OUT, EPNUM_CDC_1_IN, 64),
+};
+
+#if TUD_OPT_HIGH_SPEED
+// Per USB specs: high speed capable device must report device_qualifier and other_speed_configuration
+
+uint8_t const desc_hs_configuration[] =
+{
+  // Config number, interface count, string index, total length, attribute, power in mA
+  TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+  // 1st CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_0, 4, EPNUM_CDC_0_NOTIF, 8, EPNUM_CDC_0_OUT, EPNUM_CDC_0_IN, 512),
+
+  // 2nd CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_1, 4, EPNUM_CDC_1_NOTIF, 8, EPNUM_CDC_1_OUT, EPNUM_CDC_1_IN, 512),
+};
+
+// device qualifier is mostly similar to device descriptor since we don't change configuration based on speed
+tusb_desc_device_qualifier_t const desc_device_qualifier =
+{
+  .bLength            = sizeof(tusb_desc_device_t),
+  .bDescriptorType    = TUSB_DESC_DEVICE,
+  .bcdUSB             = USB_BCD,
+
+  .bDeviceClass       = TUSB_CLASS_MISC,
+  .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+  .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+
+  .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+  .bNumConfigurations = 0x01,
+  .bReserved          = 0x00
+};
+
+// Invoked when received GET DEVICE QUALIFIER DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete.
+// device_qualifier descriptor describes information about a high-speed capable device that would
+// change if the device were operating at the other speed. If not highspeed capable stall this request.
+uint8_t const* tud_descriptor_device_qualifier_cb(void)
+{
+  return (uint8_t const*) &desc_device_qualifier;
+}
+
+// Invoked when received GET OTHER SEED CONFIGURATION DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
+// Configuration descriptor in the other speed e.g if high speed then this is for full speed and vice versa
+uint8_t const* tud_descriptor_other_speed_configuration_cb(uint8_t index)
+{
+  (void) index; // for multiple configurations
+
+  // if link speed is high return fullspeed config, and vice versa
+  return (tud_speed_get() == TUSB_SPEED_HIGH) ?  desc_fs_configuration : desc_hs_configuration;
+}
+
+#endif // highspeed
+
+// Invoked when received GET CONFIGURATION DESCRIPTOR
+// Application return pointer to descriptor
+// Descriptor contents must exist long enough for transfer to complete
+uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
+{
+  (void) index; // for multiple configurations
+
+#if TUD_OPT_HIGH_SPEED
+  // Although we are highspeed, host may be fullspeed.
+  return (tud_speed_get() == TUSB_SPEED_HIGH) ?  desc_hs_configuration : desc_fs_configuration;
+#else
+  return desc_fs_configuration;
+#endif
+}
+
+//--------------------------------------------------------------------+
+// String Descriptors
+//--------------------------------------------------------------------+
+
+// array of pointer to string descriptors
+char const* string_desc_arr [] =
+{
+  (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
+  "TinyUSB",                     // 1: Manufacturer
+  "TinyUSB Device",              // 2: Product
+  "123456",                      // 3: Serials, should use chip ID
+  "TinyUSB CDC",                 // 4: CDC Interface
+};
+
+static uint16_t _desc_str[32];
+
+// Invoked when received GET STRING DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
+uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid)
+{
+  (void) langid;
+
+  uint8_t chr_count;
+
+  if ( index == 0)
+  {
+    memcpy(&_desc_str[1], string_desc_arr[0], 2);
+    chr_count = 1;
+  }else
+  {
+    // Note: the 0xEE index string is a Microsoft OS 1.0 Descriptors.
+    // https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors
+
+    if ( !(index < sizeof(string_desc_arr)/sizeof(string_desc_arr[0])) ) return NULL;
+
+    const char* str = string_desc_arr[index];
+
+    // Cap at max char
+    chr_count = (uint8_t) strlen(str);
+    if ( chr_count > 31 ) chr_count = 31;
+
+    // Convert ASCII string into UTF-16
+    for(uint8_t i=0; i<chr_count; i++)
+    {
+      _desc_str[1+i] = str[i];
+    }
+  }
+
+  // first byte is length (including header), second byte is string type
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8 ) | (2*chr_count + 2));
+
+  return _desc_str;
+}