text: #include <string.h>
  
  #include "lib/mp-readline/readline.h"
  #include "lib/utils/interrupt_char.h"
  #include "py/mphal.h"
  #include "py/mpstate.h"
  #include "py/runtime.h"
  #include "py/smallint.h"
  #include "shared-bindings/microcontroller/__init__.h"
  #include "shared-bindings/time/__init__.h"
  #include "supervisor/shared/autoreload.h"
  
  #include "hal/include/hal_atomic.h"
  #include "hal/include/hal_delay.h"
  #include "hal/include/hal_gpio.h"
  #include "hal/include/hal_sleep.h"
  
  #include "mpconfigboard.h"
  #include "mphalport.h"
  #include "reset.h"
  #include "tick.h"
  #include "usb.h"
  
  extern struct usart_module usart_instance;
  
  int mp_hal_stdin_rx_chr(void) {
      for (;;) {
          #ifdef MICROPY_VM_HOOK_LOOP
              MICROPY_VM_HOOK_LOOP
          #endif
          // if (reload_next_character) {
          //     return CHAR_CTRL_D;
          // }
          if (usb_bytes_available()) {
              #ifdef MICROPY_HW_LED_RX
              gpio_toggle_pin_level(MICROPY_HW_LED_RX);
              #endif
              return usb_read();
          }
      }
  }
  
  void mp_hal_stdout_tx_strn(const char *str, size_t len) {
      #ifdef MICROPY_HW_LED_TX
      gpio_toggle_pin_level(MICROPY_HW_LED_TX);
      #endif
  
      #ifdef CIRCUITPY_BOOT_OUTPUT_FILE
      if (boot_output_file != NULL) {
          UINT bytes_written = 0;
          f_write(boot_output_file, str, len, &bytes_written);
      }
      #endif
  
      usb_write(str, len);
  }
  
  void mp_hal_delay_ms(mp_uint_t delay) {
      uint64_t start_tick = ticks_ms;
      uint64_t duration = 0;
      while (duration < delay) {
          #ifdef MICROPY_VM_HOOK_LOOP
              MICROPY_VM_HOOK_LOOP
          #endif
          // Check to see if we've been CTRL-Ced by autoreload or the user.
          if(MP_STATE_VM(mp_pending_exception) == MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_kbd_exception))) {
              break;
          }
          duration = (ticks_ms - start_tick);
          // TODO(tannewt): Go to sleep for a little while while we wait.
      }
  }
  
  void mp_hal_delay_us(mp_uint_t delay) {
      tick_delay(delay);
  }
  
  void mp_hal_disable_all_interrupts(void) {
      common_hal_mcu_disable_interrupts();
  }
  
  void mp_hal_enable_all_interrupts(void) {
      common_hal_mcu_enable_interrupts();
  }
  