Make enums into implicit char

Marlin/src/HAL/HAL_DUE/usb/genclk.h

 //! \name Programmable Clock Sources (PCK)
 //@{
 
-enum genclk_source {
+enum genclk_source : char {
 	GENCLK_PCK_SRC_SLCK_RC       = 0, //!< Internal 32kHz RC oscillator as PCK source clock
 	GENCLK_PCK_SRC_SLCK_XTAL     = 1, //!< External 32kHz crystal oscillator as PCK source clock
 	GENCLK_PCK_SRC_SLCK_BYPASS   = 2, //!< External 32kHz bypass oscillator as PCK source clock
 //! \name Programmable Clock Prescalers (PCK)
 //@{
 
-enum genclk_divider {
+enum genclk_divider : char {
 	GENCLK_PCK_PRES_1  = PMC_PCK_PRES_CLK_1, //!< Set PCK clock prescaler to 1
 	GENCLK_PCK_PRES_2  = PMC_PCK_PRES_CLK_2, //!< Set PCK clock prescaler to 2
 	GENCLK_PCK_PRES_4  = PMC_PCK_PRES_CLK_4, //!< Set PCK clock prescaler to 4

Marlin/src/HAL/HAL_DUE/usb/pll.h

 
 #define PLL_COUNT           0x3fU
 
-enum pll_source {
+enum pll_source : char {
 	PLL_SRC_MAINCK_4M_RC        = OSC_MAINCK_4M_RC,     //!< Internal 4MHz RC oscillator.
 	PLL_SRC_MAINCK_8M_RC        = OSC_MAINCK_8M_RC,     //!< Internal 8MHz RC oscillator.
 	PLL_SRC_MAINCK_12M_RC       = OSC_MAINCK_12M_RC,    //!< Internal 12MHz RC oscillator.

Marlin/src/HAL/HAL_DUE/usb/sbc_protocol.h

 //! \name SBC-2 Mode page definitions
 //@{
 
-enum scsi_sbc_mode {
+enum scsi_sbc_mode : char {
 	SCSI_MS_MODE_RW_ERR_RECOV = 0x01,	//!< Read-Write Error Recovery mode page
 	SCSI_MS_MODE_FORMAT_DEVICE = 0x03,	//!< Format Device mode page
 	SCSI_MS_MODE_FLEXIBLE_DISK = 0x05,	//!< Flexible Disk mode page

Marlin/src/HAL/HAL_DUE/usb/spc_protocol.h

 COMPILER_PACK_RESET()
 
 /* Vital Product Data page codes */
-enum scsi_vpd_page_code {
+enum scsi_vpd_page_code : char {
 	SCSI_VPD_SUPPORTED_PAGES = 0x00,
 	SCSI_VPD_UNIT_SERIAL_NUMBER = 0x80,
 	SCSI_VPD_DEVICE_IDENTIFICATION = 0x83,
 
 
 /* Sense keys */
-enum scsi_sense_key {
+enum scsi_sense_key : char {
 	SCSI_SK_NO_SENSE = 0x0,
 	SCSI_SK_RECOVERED_ERROR = 0x1,
 	SCSI_SK_NOT_READY = 0x2,
 };
 
 /* Additional Sense Code / Additional Sense Code Qualifier pairs */
-enum scsi_asc_ascq {
+enum scsi_asc_ascq : char {
 	SCSI_ASC_NO_ADDITIONAL_SENSE_INFO = 0x0000,
 	SCSI_ASC_LU_NOT_READY_REBUILD_IN_PROGRESS = 0x0405,
 	SCSI_ASC_WRITE_ERROR = 0x0c00,
  * used with MODE SELECT and MODE SENSE commands
  * that are applicable to all SCSI devices.
  */
-enum scsi_spc_mode {
+enum scsi_spc_mode : char {
 	SCSI_MS_MODE_VENDOR_SPEC = 0x00,
 	SCSI_MS_MODE_INFEXP = 0x1C,    // Informational exceptions control page
 	SCSI_MS_MODE_ALL = 0x3f,
 };
 
 
-enum scsi_spc_mode_sense_pc {
+enum scsi_spc_mode_sense_pc : char {
 	SCSI_MS_SENSE_PC_CURRENT = 0,
 	SCSI_MS_SENSE_PC_CHANGEABLE = 1,
 	SCSI_MS_SENSE_PC_DEFAULT = 2,

Marlin/src/HAL/HAL_DUE/usb/usb_protocol.h

 /**
  * \brief Standard USB requests (bRequest)
  */
-enum usb_reqid {
+enum usb_reqid : char {
 	USB_REQ_GET_STATUS = 0,
 	USB_REQ_CLEAR_FEATURE = 1,
 	USB_REQ_SET_FEATURE = 3,
  * \brief Standard USB device status flags
  *
  */
-enum usb_device_status {
+enum usb_device_status : char {
 	USB_DEV_STATUS_BUS_POWERED = 0,
 	USB_DEV_STATUS_SELF_POWERED = 1,
 	USB_DEV_STATUS_REMOTEWAKEUP = 2
  * \brief Standard USB Interface status flags
  *
  */
-enum usb_interface_status {
+enum usb_interface_status : char {
 	USB_IFACE_STATUS_RESERVED = 0
 };
 
  * \brief Standard USB endpoint status flags
  *
  */
-enum usb_endpoint_status {
+enum usb_endpoint_status : char {
 	USB_EP_STATUS_HALTED = 1,
 };
 
  *
  * \note valid for SetFeature request.
  */
-enum usb_device_feature {
+enum usb_device_feature : char {
 	USB_DEV_FEATURE_REMOTE_WAKEUP = 1, //!< Remote wakeup enabled
 	USB_DEV_FEATURE_TEST_MODE = 2,     //!< USB test mode
 	USB_DEV_FEATURE_OTG_B_HNP_ENABLE = 3,
  *
  * \note valid for USB_DEV_FEATURE_TEST_MODE request.
  */
-enum usb_device_hs_test_mode {
+enum usb_device_hs_test_mode : char {
 	USB_DEV_TEST_MODE_J = 1,
 	USB_DEV_TEST_MODE_K = 2,
 	USB_DEV_TEST_MODE_SE0_NAK = 3,
 /**
  * \brief Standard USB endpoint feature/status flags
  */
-enum usb_endpoint_feature {
+enum usb_endpoint_feature : char {
 	USB_EP_FEATURE_HALT = 0,
 };
 
 /**
  * \brief Standard USB Test Mode Selectors
  */
-enum usb_test_mode_selector {
+enum usb_test_mode_selector : char {
 	USB_TEST_J = 0x01,
 	USB_TEST_K = 0x02,
 	USB_TEST_SE0_NAK = 0x03,
 /**
  * \brief Standard USB descriptor types
  */
-enum usb_descriptor_type {
+enum usb_descriptor_type : char {
 	USB_DT_DEVICE = 1,
 	USB_DT_CONFIGURATION = 2,
 	USB_DT_STRING = 3,
 /**
  * \brief USB Device Capability types
  */
-enum usb_capability_type {
+enum usb_capability_type : char {
 	USB_DC_USB20_EXTENSION = 0x02,
 };
 
  * \brief USB Device Capability - USB 2.0 Extension
  * To fill bmAttributes field of usb_capa_ext_desc_t structure.
  */
-enum usb_capability_extension_attr {
+enum usb_capability_extension_attr : char {
 	USB_DC_EXT_LPM  = 0x00000002,
 };
 
 /**
  * \brief Standard USB endpoint transfer types
  */
-enum usb_ep_type {
+enum usb_ep_type : char {
 	USB_EP_TYPE_CONTROL = 0x00,
 	USB_EP_TYPE_ISOCHRONOUS = 0x01,
 	USB_EP_TYPE_BULK = 0x02,
 /**
  * \brief Standard USB language IDs for string descriptors
  */
-enum usb_langid {
+enum usb_langid : char {
 	USB_LANGID_EN_US = 0x0409, //!< English (United States)
 };
 

Marlin/src/HAL/HAL_DUE/usb/usb_protocol_cdc.h

 	uint8_t bDataBits;
 } usb_cdc_line_coding_t;
 //! Possible values of bCharFormat
-enum cdc_char_format {
+enum cdc_char_format : char {
 	CDC_STOP_BITS_1 = 0,	//!< 1 stop bit
 	CDC_STOP_BITS_1_5 = 1,	//!< 1.5 stop bits
 	CDC_STOP_BITS_2 = 2,	//!< 2 stop bits
 };
 //! Possible values of bParityType
-enum cdc_parity {
+enum cdc_parity : char {
 	CDC_PAR_NONE = 0,	//!< No parity
 	CDC_PAR_ODD = 1,	//!< Odd parity
 	CDC_PAR_EVEN = 2,	//!< Even parity

Marlin/src/HAL/HAL_DUE/usb/usb_protocol_msc.h

 /**
  * \brief MSC USB requests (bRequest)
  */
-enum usb_reqid_msc {
+enum usb_reqid_msc : unsigned char {
 	USB_REQ_MSC_BULK_RESET = 0xFF,	//!< Mass Storage Reset
-	USB_REQ_MSC_GET_MAX_LUN = 0xFE,	//!< Get Max LUN
+	USB_REQ_MSC_GET_MAX_LUN = 0xFE 	//!< Get Max LUN
 };
 
 

Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.cpp

   #endif
 };
 
-enum TEMP_PINS {
+enum TEMP_PINS : char {
   #if HAS_TEMP_0
     TEMP_0,
   #endif

Marlin/src/core/enum.h

  *  - X_HEAD and Y_HEAD is used for systems that don't have a 1:1 relationship
  *    between X_AXIS and X Head movement, like CoreXY bots
  */
-enum AxisEnum {
-  NO_AXIS   = -1,
+enum AxisEnum : unsigned char {
   X_AXIS    = 0,
   A_AXIS    = 0,
   Y_AXIS    = 1,
   X_HEAD    = 4,
   Y_HEAD    = 5,
   Z_HEAD    = 6,
-  ALL_AXES  = 100
+  ALL_AXES  = 0xFE,
+  NO_AXIS   = 0xFF
 };
 
 #define LOOP_S_LE_N(VAR, S, N) for (uint8_t VAR=S; VAR<=N; VAR++)
 /**
  * SD Card
  */
-enum LsAction { LS_SerialPrint, LS_Count, LS_GetFilename };
+enum LsAction : char { LS_SerialPrint, LS_Count, LS_GetFilename };
 
 /**
  * Ultra LCD
  */
-enum LCDViewAction {
+enum LCDViewAction : char {
   LCDVIEW_NONE,
   LCDVIEW_REDRAW_NOW,
   LCDVIEW_CALL_REDRAW_NEXT,

Marlin/src/core/serial.h

 /**
  * Define debug bit-masks
  */
-enum DebugFlags {
+enum DebugFlags : unsigned char {
   DEBUG_NONE          = 0,
   DEBUG_ECHO          = _BV(0), ///< Echo commands in order as they are processed
   DEBUG_INFO          = _BV(1), ///< Print messages for code that has debug output
 };
 
 #if ENABLED(EMERGENCY_PARSER)
-  enum e_parser_state {
+  enum e_parser_state : char {
     state_RESET,
     state_N,
     state_M,

Marlin/src/feature/bedlevel/mbl/mesh_bed_leveling.h

 
 #include "../../../inc/MarlinConfig.h"
 
-enum MeshLevelingState {
+enum MeshLevelingState : char {
   MeshReport,
   MeshStart,
   MeshNext,

Marlin/src/feature/bedlevel/ubl/ubl.h

 
 // ubl_G29.cpp
 
-enum MeshPointType { INVALID, REAL, SET_IN_BITMAP };
+enum MeshPointType : char { INVALID, REAL, SET_IN_BITMAP };
 
 // External references
 

Marlin/src/feature/pause.h

 
 #include "../inc/MarlinConfigPre.h"
 
-enum AdvancedPauseMode {
+enum AdvancedPauseMode : char {
   ADVANCED_PAUSE_MODE_PAUSE_PRINT,
   ADVANCED_PAUSE_MODE_LOAD_FILAMENT,
   ADVANCED_PAUSE_MODE_UNLOAD_FILAMENT
 };
 
-enum AdvancedPauseMessage {
+enum AdvancedPauseMessage : char {
   ADVANCED_PAUSE_MESSAGE_INIT,
   ADVANCED_PAUSE_MESSAGE_UNLOAD,
   ADVANCED_PAUSE_MESSAGE_INSERT,
   ADVANCED_PAUSE_MESSAGE_WAIT_FOR_NOZZLES_TO_HEAT
 };
 
-enum AdvancedPauseMenuResponse {
+enum AdvancedPauseMenuResponse : char {
   ADVANCED_PAUSE_RESPONSE_WAIT_FOR,
   ADVANCED_PAUSE_RESPONSE_EXTRUDE_MORE,
   ADVANCED_PAUSE_RESPONSE_RESUME_PRINT

Marlin/src/feature/tmc_util.cpp

 
 #if ENABLED(TMC_DEBUG)
 
-  enum TMC_debug_enum {
+  enum TMC_debug_enum : char {
     TMC_CODES,
     TMC_ENABLED,
     TMC_CURRENT,
     TMC_HSTRT,
     TMC_SGT
   };
-  enum TMC_drv_status_enum {
+  enum TMC_drv_status_enum : char {
     TMC_DRV_CODES,
     TMC_STST,
     TMC_OLB,

Marlin/src/feature/tmc_util.h

 
 extern bool report_tmc_status;
 
-enum TMC_AxisEnum { TMC_X, TMC_X2, TMC_Y, TMC_Y2, TMC_Z, TMC_Z2, TMC_E0, TMC_E1, TMC_E2, TMC_E3, TMC_E4 };
+enum TMC_AxisEnum : char { TMC_X, TMC_X2, TMC_Y, TMC_Y2, TMC_Z, TMC_Z2, TMC_E0, TMC_E1, TMC_E2, TMC_E3, TMC_E4 };
 
 constexpr uint32_t _tmc_thrs(const uint16_t msteps, const int32_t thrs, const uint32_t spmm) {
   return 12650000UL * msteps / (256 * thrs * spmm);

Marlin/src/gcode/calibrate/G33.cpp

 constexpr uint8_t _7P_STEP = 1,              // 7-point step - to change number of calibration points
                   _4P_STEP = _7P_STEP * 2,   // 4-point step
                   NPP      = _7P_STEP * 6;   // number of calibration points on the radius
-enum CalEnum {                               // the 7 main calibration points - add definitions if needed
+enum CalEnum : char {                               // the 7 main calibration points - add definitions if needed
   CEN      = 0,
   __A      = 1,
   _AB      = __A + _7P_STEP,

Marlin/src/gcode/gcode.h

      * Workspace planes only apply to G2/G3 moves
      * (and "canned cycles" - not a current feature)
      */
-    enum WorkspacePlane { PLANE_XY, PLANE_ZX, PLANE_YZ };
+    enum WorkspacePlane : char { PLANE_XY, PLANE_ZX, PLANE_YZ };
     static WorkspacePlane workspace_plane;
   #endif
 
      * States for managing Marlin and host communication
      * Marlin sends messages if blocked or busy
      */
-    enum MarlinBusyState {
+    enum MarlinBusyState : char {
       NOT_BUSY,           // Not in a handler
       IN_HANDLER,         // Processing a GCode
       IN_PROCESS,         // Known to be blocking command input (as in G29)

Marlin/src/libs/stopwatch.h

  */
 class Stopwatch {
   private:
-    enum State {
+    enum State : char {
       STOPPED,
       RUNNING,
       PAUSED

Marlin/src/module/endstops.h

 #include "../inc/MarlinConfig.h"
 #include <stdint.h>
 
-enum EndstopEnum {
+enum EndstopEnum : char {
   X_MIN,
   Y_MIN,
   Z_MIN,

Marlin/src/module/motion.h

  */
 #if ENABLED(DUAL_X_CARRIAGE)
 
-  enum DualXMode {
+  enum DualXMode : char {
     DXC_FULL_CONTROL_MODE,  // DUAL_X_CARRIAGE only
     DXC_AUTO_PARK_MODE,     // DUAL_X_CARRIAGE only
     DXC_DUPLICATION_MODE
 
 #elif ENABLED(DUAL_NOZZLE_DUPLICATION_MODE)
 
-  enum DualXMode {
+  enum DualXMode : char {
     DXC_DUPLICATION_MODE = 2
   };
 

Marlin/src/module/planner.h

   #include "../libs/vector_3.h"
 #endif
 
-enum BlockFlagBit {
+enum BlockFlagBit : char {
   // Recalculate trapezoids on entry junction. For optimization.
   BLOCK_BIT_RECALCULATE,
 
   BLOCK_BIT_CONTINUED
 };
 
-enum BlockFlag {
+enum BlockFlag : char {
   BLOCK_FLAG_RECALCULATE          = _BV(BLOCK_BIT_RECALCULATE),
   BLOCK_FLAG_NOMINAL_LENGTH       = _BV(BLOCK_BIT_NOMINAL_LENGTH),
   BLOCK_FLAG_BUSY                 = _BV(BLOCK_BIT_BUSY),

Marlin/src/module/temperature.h

 /**
  * States for ADC reading in the ISR
  */
-enum ADCSensorState {
+enum ADCSensorState : char {
   #if HAS_TEMP_0
     PrepareTemp_0,
     MeasureTemp_0,
 
     #if ENABLED(THERMAL_PROTECTION_HOTENDS) || HAS_THERMALLY_PROTECTED_BED
 
-      typedef enum TRState { TRInactive, TRFirstHeating, TRStable, TRRunaway } TRstate;
+      typedef enum TRState : char { TRInactive, TRFirstHeating, TRStable, TRRunaway } TRstate;
 
       static void thermal_runaway_protection(TRState * const state, millis_t * const timer, const float &current, const float &target, const int8_t heater_id, const uint16_t period_seconds, const uint16_t hysteresis_degc);