mirror of
https://github.com/BotChain-Robots/firmware.git
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73 lines
3.7 KiB
C
73 lines
3.7 KiB
C
#ifdef DATA_LINK
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#define BROADCAST_ADDR 0xFF //used for discovery (finding the board's neighbours). this will mean the board ids will have 2^8-2 = 254 unique IDs that could be assigned
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#define PC_ADDR 0x0 //setting 0 to be the PC
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#define START_OF_FRAME 0xAB //0b1010_1011 - denotes the start of frame
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#define MAX_GENERIC_DATA_LEN (1 << 16) //Max 65.5KiB
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#define MAX_CONTROL_DATA_LEN (1 << 8) // Max 256B
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//Flags
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#define FLAG_FRAG 0x8 //0b1000 //this fragmented frame is part of a larger frame
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#define FLAG_DISCOVERY 0x4 //0b0100
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#define FLAG_NEIGH_TABLE 0x2 //0b0010 - used to denote the frame contains the neighbour tables (used for finding the configuration/topology of the network); similar to an ARP or MAC table
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#define FLAG_ACK 0x1 //0b0001_0000 - used for confirming receipt of different types of frames from the neighbours
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#define GET_TYPE(x) ((x) & 0xF0)
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#define GET_FLAG(x) ((x) & 0x0F)
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#define MAKE_TYPE_FLAG(type, flag) ((uint8_t)((type & 0xF0) | (flag & 0xF)))
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#define IS_CONTROL_FRAME(x) (((x) & 0x80) != 0)
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#define CONTROL_FRAME_OVERHEAD 9
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#define GENERIC_FRAME_OVERHEAD 12
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#define CONTROL_FRAME_TYPE 0x80 //if the frame type MSB is set to 1, use the control frame
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//Types (total 2^4 = 16 different types)
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enum class FrameType : uint8_t {
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MOTOR_TYPE = 0x80, //0b1000_0000
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SERVO_TYPE = 0xC0, //0b1100_0000
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DISTANCE_SENSOR_TYPE = 0xE0, //0b1110_0000
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DEBUG_CONTROL_TYPE = 0xC0, //0b1100_0000
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DEBUG_GENERIC_TYPE = 0x00, //0b0000_0000
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SYSTEM_TYPE = 0x30, //0x0011_0000 - used for statuses, discovery, and other maintainence requests
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RIP_TABLE_CONTROL = 0x90, //0b1001_0000 - using the control frame to broadcast the RIP table
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RIP_TABLE_GENERIC = 0x10 //0b0001_000 - using the generic frame to broadcast the RIP table
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};
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#pragma pack(push, 1) //these structs will be transmitted as is (ensure the structs are structured using 1B alignment - no padding)
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typedef struct _control_frame{
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uint8_t preamble; //Start of Frame
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uint8_t sender_id; //sender board id
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uint8_t receiver_id; //receiver board id
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uint16_t seq_num; //sequence number to differentiate frames being sent from sender to receiver
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uint8_t type_flag; //(type << 4) | flag - both are 4 bits
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uint16_t data_len; //Data Length (max 256B)
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uint8_t data[MAX_CONTROL_DATA_LEN]; //Variable Length of Data
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uint16_t crc_16; //CRC-16
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} control_frame; //this will have a max size of 9 + 256B = 265B
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typedef struct _data_link_frame{
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uint8_t preamble; //Start of Frame
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uint8_t sender_id; //sender board id
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uint8_t receiver_id; //receiver board id
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uint16_t seq_num; //sequence number to differentiate frames being sent from sender to receiver
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uint8_t type_flag; //(type << 4) | flag - both are 4 bits
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uint16_t frag_info; //(total_frag_num << 8) | frag_num - total_frag_num denotes the total number of fragmented frames to expect for this sequence number(?) and frag_num denotes the fragment frame num
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uint16_t data_len; //Data Length (max 178B)
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uint8_t data[MAX_GENERIC_DATA_LEN]; //Variable Length of Data
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uint16_t crc_16; //CRC-16
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} data_link_frame; //this will have a max size of ~65.5KiB
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#pragma pack(pop)
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typedef struct _header{
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uint8_t preamble; //Start of Frame
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uint8_t sender_id; //sender board id
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uint8_t receiver_id; //receiver board id
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uint16_t seq_num; //sequence number to differentiate frames being sent from sender to receiver
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uint8_t type_flag; //(type << 4) | flag - both are 4 bits
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uint16_t frag_info; //(total_frag_num << 8) | frag_num - total_frag_num denotes the total number of fragmented frames to expect for this sequence number(?) and frag_num denotes the fragment frame num
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uint16_t data_len; //Data Length (max 178B)
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uint16_t crc_16; //CRC-16
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} frame_header;
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#endif //DATA_LINK
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