#define MAGIC_MCU_MULTIFRAME    0x23542668  /* MCU MultiFrame packet            */
 
 /*
  * MCU Multi Frame packet
  *
  *
  * - One Multi Frame packet may contain multiple frames, but does not need to
  * - If the number and ids of the subframes vary in consecutive multi frame packets 
  *   then nothing is assumed about the missing subframes. This allows for incremental
  *   updates for only the screens that did change. 
  *
  */
 
 typedef struct mcu_subframe_header mcu_subframe_header_t;
 
 struct mcu_subframe_header
 {
   unsigned char screen_id;              /* screen id                                 */
   unsigned char bpp;                    /* bits per pixel, supported values: (4,8)   */
                                         /* 4 means nibbles 8 means bytes             */
   unsigned short height;                /* number of rows                            */
   unsigned short width;                 /* width in pixels of row                    */
   /*
    * followed by 
    * nibbles in [rows][columns];
    * if width is uneven one nibble is used as padding
    * or bytes[]
    *
    * the bytesize of this can be calculated using height * width in the byte case 
    *   and height * ((width + 1)/2) in case of nibbles (integer divison) 
    */
   unsigned char data[0];
 } PACKED;
 
 typedef struct mcu_multiframe_header mcu_multiframe_header_t;
 
 struct mcu_multiframe_header
 {
   unsigned int magic;                           /* == MAGIC_MCU_MULTIFRAME                   */
   unsigned int timestamp_h, timestamp_l;        /* milliseconds since epoch - e.g. gettimeofday(&tv); 
                                                    timeStamp = tv->tv_sec * 1000 + tv->tv_usec / 1000.; */
   /*
    * followed by multiple subframe headers
    */
   mcu_subframe_header_t subframe[0];
 } PACKED;

 #define MAGIC_MCU_DEVCTRL       0x23542667  /* MCU Device Control packet        */
 #define MAGIC_MCU_RESPONSE      0xFEEDBACC  /* MCU response packet              */ 
 #define MAGIC_WDIM_RESPONSE     0xFEEDBACD  /* WDIM response packet             */
 
 /*
  * MCU Device Control packet
  */
 
 #define MCU_DEVCTRL_COMMAND_SET_MCU_ID          0       /* set MCU's ID                                 */ 
 #define MCU_DEVCTRL_COMMAND_SET_LAMP_ID         1       /* set the ID of a lamp (MAC in *param)        */
 #define MCU_DEVCTRL_COMMAND_SET_GAMMA           2       /* set the gamma curve of a lamp                */
 #define MCU_DEVCTRL_COMMAND_WRITE_CONFIG        3       /* tell the MCU to write the gamma curve        */
 #define MCU_DEVCTRL_COMMAND_SET_JITTER          4       /* set the jitter for a lamp                    */
 #define MCU_DEVCTRL_COMMAND_SET_ASSIGNED_LAMPS  5       /* set lamps assigned to this MCU               */
 #define MCU_DEVCTRL_COMMAND_SEND_WDIM_STATS     6       /* check WDIM statistics                        */
 #define MCU_DEVCTRL_COMMAND_SET_DIMMER_DELAY    8       /* set dimmer delay                             */
 #define MCU_DEVCTRL_COMMAND_SET_DIMMER_CONTROL  9       /* set dimmer control (force off)               */
 #define MCU_DEVCTRL_COMMAND_SET_RF_POWER        10      /* set RF power level                           */
 #define MCU_DEVCTRL_COMMAND_SET_JAM_DENSITY     11      /* set JAM density (pkt / ms)                   */
 #define MCU_DEVCTRL_COMMAND_SEND_WMCU_STATS     12      /* check WMCU stats                             */
 #define MCU_DEVCTRL_COMMAND_RESET_MCU           13      /* reset WMCU                                   */
 #define MCU_DEVCTRL_COMMAND_RESET_WDIM          14      /* reset WMCU                                   */
 #define MCU_DEVCTRL_COMMAND_OUTPUT_RAW          0xff    /* DEBUG: output raw RF packet                  */
 
 typedef struct mcu_devctrl_header  mcu_devctrl_header_t;
 
 struct mcu_devctrl_header
 {
   unsigned int magic;         /* == MAGIC_MCU_DEVCTRL                   */
   unsigned int command;       /* MCU_DEVCTRL_COMMAND_*                  */
   unsigned int mac;           /* LAMP MAC address (if needed)           */
   unsigned int value;
   /* params consume the rest of the packet, up to MTU */
   unsigned int param[0];
 } PACKED;