text: // Module for interfacing with adc
  
  #include "module.h"
  #include "lauxlib.h"
  #include "platform.h"
  
  #include "c_types.h"
  #include "user_interface.h"
  
  // Lua: read(id) , return system adc
  static int adc_sample( lua_State* L )
  {
    unsigned id = luaL_checkinteger( L, 1 );
    MOD_CHECK_ID( adc, id );
    unsigned val = 0xFFFF & system_adc_read();
    lua_pushinteger( L, val );
    return 1; 
  }
  
  // Lua: readvdd33()
  static int adc_readvdd33( lua_State* L )
  {
    lua_pushinteger(L, system_get_vdd33 ());
    return 1;
  }
  
  // Lua: adc.force_init_mode(x)
  static int adc_init107( lua_State *L )
  {
    uint8_t byte107 = luaL_checkinteger (L, 1);
  
    uint32 init_sector = flash_safe_get_sec_num () - 4;
  
    // Note 32bit alignment so we can safely cast to uint32 for the flash api
    char init_data[SPI_FLASH_SEC_SIZE] __attribute__((aligned(4)));
  
    if (SPI_FLASH_RESULT_OK != flash_safe_read (
      init_sector * SPI_FLASH_SEC_SIZE,
      (uint32 *)init_data, sizeof(init_data)))
        return luaL_error(L, "flash read error");
  
    // If it's already the correct value, we don't need to force it
    if (init_data[107] == byte107)
    {
      lua_pushboolean (L, false);
      return 1;
    }
  
    // Nope, it differs, we need to rewrite it
    init_data[107] = byte107;
    if (SPI_FLASH_RESULT_OK != flash_safe_erase_sector (init_sector))
      return luaL_error(L, "flash erase error");
  
    if (SPI_FLASH_RESULT_OK != flash_safe_write (
      init_sector * SPI_FLASH_SEC_SIZE,
      (uint32 *)init_data, sizeof(init_data)))
        return luaL_error(L, "flash write error");
  
    lua_pushboolean (L, true);
    return 1;
  }
  
  // Module function map
  static const LUA_REG_TYPE adc_map[] = {
    { LSTRKEY( "read" ),      LFUNCVAL( adc_sample ) },
    { LSTRKEY( "readvdd33" ), LFUNCVAL( adc_readvdd33 ) },
    { LSTRKEY( "force_init_mode" ), LFUNCVAL( adc_init107 ) },
    { LSTRKEY( "INIT_ADC" ),  LNUMVAL( 0x00 ) },
    { LSTRKEY( "INIT_VDD33" ),LNUMVAL( 0xff ) },
    { LNILKEY, LNILVAL }
  };
  
  NODEMCU_MODULE(ADC, "adc", adc_map, NULL);
  