diff --git a/hw/bsp/board.h b/hw/bsp/board.h
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+++ b/hw/bsp/board.h
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+/* 
+ * 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.
+ */
+
+/** \ingroup group_demo
+ * \defgroup group_board Boards Abstraction Layer
+ *  @{ */
+
+#ifndef _BSP_BOARD_H_
+#define _BSP_BOARD_H_
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "ansi_escape.h"
+#include "tusb.h"
+
+#define CFG_BOARD_UART_BAUDRATE    115200
+
+//--------------------------------------------------------------------+
+// Board Porting API
+// For simplicity, only one LED and one Button are used
+//--------------------------------------------------------------------+
+
+// Initialize on-board peripherals : led, button, uart and USB
+void board_init(void);
+
+// Turn LED on or off
+void board_led_write(bool state);
+
+// Control led pattern using phase duration in ms.
+// For each phase, LED is toggle then repeated, board_led_task() is required to be called
+//void board_led_pattern(uint32_t const phase_ms[], uint8_t count);
+
+// Get the current state of button
+// a '1' means active (pressed), a '0' means inactive.
+uint32_t board_button_read(void);
+
+// Get characters from UART
+int board_uart_read(uint8_t* buf, int len);
+
+// Send characters to UART
+int board_uart_write(void const * buf, int len);
+
+#if CFG_TUSB_OS == OPT_OS_NONE
+  // Get current milliseconds, must be implemented when no RTOS is used
+  uint32_t board_millis(void);
+
+#elif CFG_TUSB_OS == OPT_OS_FREERTOS
+  static inline uint32_t board_millis(void)
+  {
+    return ( ( ((uint64_t) xTaskGetTickCount()) * 1000) / configTICK_RATE_HZ );
+  }
+
+#elif CFG_TUSB_OS == OPT_OS_MYNEWT
+  static inline uint32_t board_millis(void)
+  {
+    return os_time_ticks_to_ms32( os_time_get() );
+  }
+
+#elif CFG_TUSB_OS == OPT_OS_PICO
+  #include "pico/time.h"
+  static inline uint32_t board_millis(void)
+  {
+    return to_ms_since_boot(get_absolute_time());
+  }
+
+#elif CFG_TUSB_OS == OPT_OS_RTTHREAD
+  static inline uint32_t board_millis(void)
+  {
+    return (((uint64_t)rt_tick_get()) * 1000 / RT_TICK_PER_SECOND);
+  }
+
+#else
+  #error "board_millis() is not implemented for this OS"
+#endif
+
+//--------------------------------------------------------------------+
+// Helper functions
+//--------------------------------------------------------------------+
+static inline void board_led_on(void)
+{
+  board_led_write(true);
+}
+
+static inline void board_led_off(void)
+{
+  board_led_write(false);
+}
+
+// TODO remove
+static inline void board_delay(uint32_t ms)
+{
+  uint32_t start_ms = board_millis();
+  while (board_millis() - start_ms < ms)
+  {
+    #if TUSB_OPT_DEVICE_ENABLED
+    // take chance to run usb background
+    tud_task();
+    #endif
+  }
+}
+
+static inline int board_uart_getchar(void)
+{
+  uint8_t c;
+  return board_uart_read(&c, 1) ? (int) c : (-1);
+}
+
+static inline int board_uart_putchar(uint8_t c)
+{
+  return board_uart_write(&c, 1);
+}
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif /* _BSP_BOARD_H_ */
+
+/** @} */