diff --git a/src/tusb.c b/src/tusb.c
new file mode 100644
index 0000000..9583f50
--- /dev/null
+++ b/src/tusb.c
@@ -0,0 +1,245 @@
+/*
+ * 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 "tusb_option.h"
+
+#if TUSB_OPT_HOST_ENABLED || TUSB_OPT_DEVICE_ENABLED
+
+#include "tusb.h"
+
+// TODO clean up
+#if TUSB_OPT_DEVICE_ENABLED
+#include "device/usbd_pvt.h"
+#endif
+
+bool tusb_init(void)
+{
+#if TUSB_OPT_DEVICE_ENABLED
+  TU_ASSERT ( tud_init(TUD_OPT_RHPORT) ); // init device stack
+#endif
+
+#if TUSB_OPT_HOST_ENABLED
+  TU_ASSERT( tuh_init(TUH_OPT_RHPORT) ); // init host stack
+#endif
+
+  return true;
+}
+
+bool tusb_inited(void)
+{
+  bool ret = false;
+
+#if TUSB_OPT_DEVICE_ENABLED
+  ret = ret || tud_inited();
+#endif
+
+#if TUSB_OPT_HOST_ENABLED
+  ret = ret || tuh_inited();
+#endif
+
+  return ret;
+}
+
+//--------------------------------------------------------------------+
+// Internal Helper for both Host and Device stack
+//--------------------------------------------------------------------+
+
+bool tu_edpt_validate(tusb_desc_endpoint_t const * desc_ep, tusb_speed_t speed)
+{
+  uint16_t const max_packet_size = tu_edpt_packet_size(desc_ep);
+  TU_LOG2("  Open EP %02X with Size = %u\r\n", desc_ep->bEndpointAddress, max_packet_size);
+
+  switch (desc_ep->bmAttributes.xfer)
+  {
+    case TUSB_XFER_ISOCHRONOUS:
+    {
+      uint16_t const spec_size = (speed == TUSB_SPEED_HIGH ? 1024 : 1023);
+      TU_ASSERT(max_packet_size <= spec_size);
+    }
+    break;
+
+    case TUSB_XFER_BULK:
+      if (speed == TUSB_SPEED_HIGH)
+      {
+        // Bulk highspeed must be EXACTLY 512
+        TU_ASSERT(max_packet_size == 512);
+      }else
+      {
+        // TODO Bulk fullspeed can only be 8, 16, 32, 64
+        TU_ASSERT(max_packet_size <= 64);
+      }
+    break;
+
+    case TUSB_XFER_INTERRUPT:
+    {
+      uint16_t const spec_size = (speed == TUSB_SPEED_HIGH ? 1024 : 64);
+      TU_ASSERT(max_packet_size <= spec_size);
+    }
+    break;
+
+    default: return false;
+  }
+
+  return true;
+}
+
+void tu_edpt_bind_driver(uint8_t ep2drv[][2], tusb_desc_interface_t const* desc_itf, uint16_t desc_len, uint8_t driver_id)
+{
+  uint8_t const* p_desc = (uint8_t const*) desc_itf;
+  uint8_t const* desc_end = p_desc + desc_len;
+
+  while( p_desc < desc_end )
+  {
+    if ( TUSB_DESC_ENDPOINT == tu_desc_type(p_desc) )
+    {
+      uint8_t const ep_addr = ((tusb_desc_endpoint_t const*) p_desc)->bEndpointAddress;
+
+      TU_LOG(2, "  Bind EP %02x to driver id %u\r\n", ep_addr, driver_id);
+      ep2drv[tu_edpt_number(ep_addr)][tu_edpt_dir(ep_addr)] = driver_id;
+    }
+
+    p_desc = tu_desc_next(p_desc);
+  }
+}
+
+uint16_t tu_desc_get_interface_total_len(tusb_desc_interface_t const* desc_itf, uint8_t itf_count, uint16_t max_len)
+{
+  uint8_t const* p_desc = (uint8_t const*) desc_itf;
+  uint16_t len = 0;
+
+  while (itf_count--)
+  {
+    // Next on interface desc
+    len += tu_desc_len(desc_itf);
+    p_desc = tu_desc_next(p_desc);
+
+    while (len < max_len)
+    {
+      // return on IAD regardless of itf count
+      if ( tu_desc_type(p_desc) == TUSB_DESC_INTERFACE_ASSOCIATION ) return len;
+
+      if ( (tu_desc_type(p_desc) == TUSB_DESC_INTERFACE) &&
+           ((tusb_desc_interface_t const*) p_desc)->bAlternateSetting == 0 )
+      {
+        break;
+      }
+
+      len += tu_desc_len(p_desc);
+      p_desc = tu_desc_next(p_desc);
+    }
+  }
+
+  return len;
+}
+
+/*------------------------------------------------------------------*/
+/* Debug
+ *------------------------------------------------------------------*/
+#if CFG_TUSB_DEBUG
+#include <ctype.h>
+
+char const* const tusb_strerr[TUSB_ERROR_COUNT] = { ERROR_TABLE(ERROR_STRING) };
+
+static void dump_str_line(uint8_t const* buf, uint16_t count)
+{
+  tu_printf("  |");
+
+  // each line is 16 bytes
+  for(uint16_t i=0; i<count; i++)
+  {
+    const char ch = buf[i];
+    tu_printf("%c", isprint(ch) ? ch : '.');
+  }
+
+  tu_printf("|\r\n");
+}
+
+/* Print out memory contents
+ *  - buf   : buffer
+ *  - count : number of item
+ *  - indent: prefix spaces on every line
+ */
+void tu_print_mem(void const *buf, uint32_t count, uint8_t indent)
+{
+  uint8_t const size = 1; // fixed 1 byte for now
+
+  if ( !buf || !count )
+  {
+    tu_printf("NULL\r\n");
+    return;
+  }
+
+  uint8_t const *buf8 = (uint8_t const *) buf;
+
+  char format[] = "%00X";
+  format[2] += 2*size;
+
+  const uint8_t item_per_line  = 16 / size;
+
+  for(unsigned int i=0; i<count; i++)
+  {
+    unsigned int value=0;
+
+    if ( i%item_per_line == 0 )
+    {
+      // Print Ascii
+      if ( i != 0 )
+      {
+        dump_str_line(buf8-16, 16);
+      }
+
+      for(uint8_t s=0; s < indent; s++) tu_printf(" ");
+
+      // print offset or absolute address
+      tu_printf("%04X: ", 16*i/item_per_line);
+    }
+
+    memcpy(&value, buf8, size);
+    buf8 += size;
+
+    tu_printf(" ");
+    tu_printf(format, value);
+  }
+
+  // fill up last row to 16 for printing ascii
+  const uint32_t remain = count%16;
+  uint8_t nback = (remain ? remain : 16);
+
+  if ( remain )
+  {
+    for(uint32_t i=0; i< 16-remain; i++)
+    {
+      tu_printf(" ");
+      for(int j=0; j<2*size; j++) tu_printf(" ");
+    }
+  }
+
+  dump_str_line(buf8-nback, nback);
+}
+
+#endif
+
+#endif // host or device enabled