/*---------------------------------------------------------------------------- ** ** Commands.c ** ** Interpretation of commands received via the radio receiver, and initiation ** of processes based on those commands and the current robot state. ** **--------------------------------------------------------------------------*/ #include "Hardware.h" #include "Onboard.h" #include "Shutdown.h" // Forward prototypes void ProcessCommand(void); // This enum is the state machine for command reception enum { WAITING_FOR_START_1, WAITING_FOR_START_2, RECEIVING }; // This defines the position of command bytes within the packet enum { PACKET_START = 0, PACKET_SPEED = 2, PACKET_DIRECTION = 3, PACKET_WEAPONS = 4, PACKET_SPECIALS = 6, PACKET_CRC = 7 }; #define CRC_POLYNOMIAL 0x1021 #define COMMAND_BUFFER_SIZE 10 #define MAX_ERRORS 100 // // Static variables available to all functions of this module // static int ErrorCount = 0; static unsigned int crc; static int ReceiveState = WAITING_FOR_START_1; static char CommandBuffer[COMMAND_BUFFER_SIZE]; char Speed, Direction; //---------------------------------------------------------------------------- // // COMMAND STRUCTURE // // Commands come in a continuous stream of packets from the handset. Each // packet is a fixed length and is of the following format: // // Size: 2 1 1 2 2 2 Total 9 bytes. // ----------------------------------------------- // Field: | START | SPEED | DIREC | WEAPON | SPECL | CRC | // ----------------------------------------------- // // START (16 bits) // This is a constant 2 byte message 0xA55A. // // SPEED (8 bits) // Required speed. -99 to +99. // // DIREC (8 bits) // Required direction in 2 degree steps. 0 degrees is straight ahead, // 90 degrees is exact left, 270 exact right, and 180 full reverse. The // value is half of the angle required. // // WEAPON (16 bits) // A bitfield to indicate required weapon operation: // 0: Front hammer forwards // 1: Front hammer reverse // 2: Rear hammer forwards // 3: Rear hammer reverse // 4: Spear forwards // 5: Spear reverse // 6: Spear multi-throw // 7: Reserved (0) // 8: Flipper operate forwards // 9: Flipper operate reverse // 10: Extend flipper forwards // 11: Extend flipper backwards // 12: Retract flipper // 13: Operate flipper // 14: Spare // 15: Reserved (0) // // SPECL (16 bits) // Special requests: // 0: Light sequence b0 // 1: Light sequence b1 // 2: Light sequence b2 // 3: Leg assist // 4: Emergency // 5: Brandish // 6: Speed Control Method (0=Open loop, 1=Closed loop) // 7: Reserved (0) // 8: Lights - reset sequences // 9: Lights - Auto repeat // 10: Spare // 11: Spare // 12: Spare // 13: Spare // 14: Spare // 15: Reserved (0) // // CRC (16 bits) // 16 bit CRC for packet. // //---------------------------------------------------------------------------- /***** ROM LOOKUP TABLE USED IN CRC16() *****/ unsigned int ccitt_16[256] = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0 }; /*---------------------------------------------------------------------------- // // crc16 // // Perform a 16-bit CRC calculation on a buffer of data using the CCITT_16 // polynomial (0x1021). The table lookup method is used for speed. // // Returns: // CRC. // // Modification Record: // 31-May-00 Paul Hills First version from previous job! -----------------------------------------------------------------------------*/ unsigned int crc16(char *Ptr, int Count) { // Perform CRC for required number of counts. crc = CRC_POLYNOMIAL; while (Count--) crc = (crc << 8) ^ ccitt_16[(unsigned char)(crc >> 8) ^ (unsigned char)(*Ptr++)]; return crc; } /*---------------------------------------------------------------------------- // // crc8 // // Perform a 16-bit CRC calculation on a buffer of data using the CCITT_16 // polynomial (0x1021), then XOR the upper and lower bytes of the CRC. // // Returns: // Packed crc byte. // // Modification Record: // 31-May-00 Paul Hills First version translation from NEC78 assembler. -----------------------------------------------------------------------------*/ unsigned int crc8(char *Ptr, int Count) { crc16(Ptr, Count); return ((crc >> 8) ^ (crc & 0x00FF)); } /*---------------------------------------------------------------------------- // // Check message CRC // // Check that the received CRC agrees with that calculated. // // Returns: // TRUE or FALSE // // Modification Record: // 24-Jul-00 Paul Hills First version -----------------------------------------------------------------------------*/ char CheckMessageCrc(void) { if ( crc16(&(CommandBuffer[PACKET_SPEED]), PACKET_CRC-PACKET_SPEED+1) == CommandBuffer[PACKET_CRC] << 8 + CommandBuffer[PACKET_CRC+1]) return TRUE; else return FALSE; } /*---------------------------------------------------------------------------- // // IncrementErrors // // Increment the error counter, and if it is up to a threshold, perform an // emergency shutdown. // // Modification Record: // 24-Jul-00 Paul Hills First version. -----------------------------------------------------------------------------*/ void IncrementErrors(void) { if (++ErrorCount == MAX_ERRORS) EmergencyShutdown(); } /*---------------------------------------------------------------------------- // // CommandByteRx // // ISR for reception of a command byte from the radio. This is a state // machine with 3 states. First it must receive the A5 5A packet start // sequence which is the first two states, then it receives the data bytes // and CRC using the third state. // // Modification Record: // 24-Jul-00 Paul Hills First version. -----------------------------------------------------------------------------*/ interrupt [SCI_RXI2] void CommandByteRx(void) { static int CommandBufferIndex = 0; static int ByteCount = 0; // // On error, clear error and reset state machine. If received a set // number of consecutive errors, shut down. // if (RADIO_COMMS_ERRORS) { CLEAR_RADIO_COMMS_ERRORS; IncrementErrors(); ReceiveState = WAITING_FOR_START_1; } else ErrorCount = 0; // // Received another byte without error. // ByteCount++; RADIO_RECEIVE_FLAG = 0; // // Command reception state machine // switch (ReceiveState) { // Stay in this state until received an 0xA5 byte case WAITING_FOR_START_1: if (RADIO_RECEIVE_REGISTER == 0xA5) { ReceiveState = WAITING_FOR_START_2; ByteCount = 1; } break; // Stay in this state until received a 0x5A byte case WAITING_FOR_START_2: if (RADIO_RECEIVE_REGISTER == 0x5A) ReceiveState = RECEIVING; break; // Now receiving data bytes & CRC case RECEIVING: // Get byte into receive buffer CommandBuffer[CommandBufferIndex++] = RADIO_RECEIVE_REGISTER; if (ByteCount == PACKET_CRC+1) // crc is 2 bytes { // If CRC is OK, process the command. if (CheckMessageCrc() == TRUE) { // Now got a good packet, process packet and clear // error counter. ProcessCommand(); ErrorCount = 0; } else { // Received a dodgy packet, so increment error counter and // shutdown if necessary. IncrementErrors(); } CommandBufferIndex = 0; ReceiveState = WAITING_FOR_START_1; } break; // Should never get to this state. Recover by jump to first state. default: CommandBufferIndex = 0; ReceiveState = WAITING_FOR_START_1; break; } } /*---------------------------------------------------------------------------- // // FillFlagArray // // Sets the flag array values based on bits in the command buffer. // // Modification Record: // 24-Jul-00 Paul Hills First version -----------------------------------------------------------------------------*/ void FillFlagArray(char *ArrayPtr, int Values, int Length) { int i; for (i=0 ; i>= 1; } } /*---------------------------------------------------------------------------- // // ProcessCommand // // Process the commands stored in the receive buffer. This function is called // after the CRC has been received and checked by the CommandByteRx() ISR. // // Modification Record: // 24-Jul-00 Paul Hills First version -----------------------------------------------------------------------------*/ void ProcessCommand(void) { // // Set globals now a validated packet has been received. // FillFlagArray(SpeedRequest, CommandBuffer[PACKET_SPEED], 8); FillFlagArray(DirectionRequest, CommandBuffer[PACKET_DIRECTION], 8); FillFlagArray(WeaponsRequest, CommandBuffer[PACKET_WEAPONS], 16); FillFlagArray(SpecialsRequest, CommandBuffer[PACKET_SPECIALS], 16); Speed = CommandBuffer[PACKET_SPEED]; Direction = CommandBuffer[PACKET_DIRECTION]; }