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Dependencies: L432KC_SPI_Pey_Lal
protocol.cpp@116:6dfcafa00e42, 2022-05-23 (annotated)
- Committer:
- voltxd
- Date:
- Mon May 23 12:55:02 2022 +0000
- Revision:
- 116:6dfcafa00e42
- Parent:
- 115:156b8234f2de
vitesse
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
voltxd | 110:a6d1d3525014 | 1 | #include "protocol.h" |
voltxd | 116:6dfcafa00e42 | 2 | #include "toolbox.hpp" |
voltxd | 110:a6d1d3525014 | 3 | |
voltxd | 110:a6d1d3525014 | 4 | char newDataAvailable = 0; |
voltxd | 110:a6d1d3525014 | 5 | |
voltxd | 116:6dfcafa00e42 | 6 | //Bytewise XOR checksum |
voltxd | 116:6dfcafa00e42 | 7 | char calculateChecksum(char command, char* payload, char payloadLength) //Use only when receiving frames |
voltxd | 110:a6d1d3525014 | 8 | { |
voltxd | 110:a6d1d3525014 | 9 | char checksum = 0xff; |
voltxd | 115:156b8234f2de | 10 | checksum ^= command; |
voltxd | 115:156b8234f2de | 11 | for (int i = 0; i < payloadLength; i++) |
voltxd | 115:156b8234f2de | 12 | checksum ^= payload[i]; |
voltxd | 110:a6d1d3525014 | 13 | return checksum; |
voltxd | 110:a6d1d3525014 | 14 | } |
voltxd | 110:a6d1d3525014 | 15 | |
voltxd | 116:6dfcafa00e42 | 16 | char calculateChecksum(char *msg) //Use only when emitting speed frames |
voltxd | 116:6dfcafa00e42 | 17 | { |
voltxd | 116:6dfcafa00e42 | 18 | int i = 0; |
voltxd | 116:6dfcafa00e42 | 19 | char checksum = msg[i++]; |
voltxd | 116:6dfcafa00e42 | 20 | for (; i < 5; i++) |
voltxd | 116:6dfcafa00e42 | 21 | checksum ^= msg[i]; |
voltxd | 116:6dfcafa00e42 | 22 | return checksum; |
voltxd | 116:6dfcafa00e42 | 23 | } |
voltxd | 116:6dfcafa00e42 | 24 | |
voltxd | 116:6dfcafa00e42 | 25 | void encodeMessage(char *msg, float vitesse) |
voltxd | 116:6dfcafa00e42 | 26 | { |
voltxd | 116:6dfcafa00e42 | 27 | msg[0] = 0xff; |
voltxd | 116:6dfcafa00e42 | 28 | convertFloatToBytes(&vitesse, msg, 1); |
voltxd | 116:6dfcafa00e42 | 29 | msg[5] = calculateChecksum(msg); |
voltxd | 116:6dfcafa00e42 | 30 | } |
voltxd | 116:6dfcafa00e42 | 31 | |
voltxd | 110:a6d1d3525014 | 32 | char receiveState = STATE_START_OF_FRAME; |
voltxd | 110:a6d1d3525014 | 33 | char receiveIndex = 0; |
voltxd | 115:156b8234f2de | 34 | char receiveIndexLimit; |
voltxd | 115:156b8234f2de | 35 | char receivedCommand; |
voltxd | 115:156b8234f2de | 36 | char receivedPayload[PAYLOAD_MAX_SIZE] = {0}; |
voltxd | 110:a6d1d3525014 | 37 | |
voltxd | 115:156b8234f2de | 38 | char verifiedPayload[PAYLOAD_MAX_SIZE] = {0}; |
voltxd | 115:156b8234f2de | 39 | char verifiedIndexLimit; |
voltxd | 115:156b8234f2de | 40 | char verifiedCommand; |
voltxd | 110:a6d1d3525014 | 41 | |
voltxd | 111:f11575e7c79b | 42 | //Decode the bytes received according to their order of reception. |
voltxd | 110:a6d1d3525014 | 43 | void decodeMessage(char c) |
voltxd | 110:a6d1d3525014 | 44 | { |
voltxd | 110:a6d1d3525014 | 45 | switch(receiveState) |
voltxd | 110:a6d1d3525014 | 46 | { |
voltxd | 110:a6d1d3525014 | 47 | case STATE_START_OF_FRAME: |
voltxd | 110:a6d1d3525014 | 48 | //Checking if we received the start Byte |
voltxd | 110:a6d1d3525014 | 49 | if (c == 0xff) |
voltxd | 110:a6d1d3525014 | 50 | { |
voltxd | 115:156b8234f2de | 51 | receiveState = STATE_COMMAND_TYPE; |
voltxd | 110:a6d1d3525014 | 52 | receiveIndex = 0; |
voltxd | 110:a6d1d3525014 | 53 | } |
voltxd | 110:a6d1d3525014 | 54 | break; |
voltxd | 110:a6d1d3525014 | 55 | |
voltxd | 115:156b8234f2de | 56 | case STATE_COMMAND_TYPE: |
voltxd | 115:156b8234f2de | 57 | receivedCommand = c; |
voltxd | 115:156b8234f2de | 58 | receiveState = STATE_PAYLOAD; |
voltxd | 115:156b8234f2de | 59 | switch(receivedCommand) |
voltxd | 110:a6d1d3525014 | 60 | { |
voltxd | 115:156b8234f2de | 61 | case COMMAND_PWM: |
voltxd | 115:156b8234f2de | 62 | receiveIndexLimit = 4; |
voltxd | 115:156b8234f2de | 63 | break; |
voltxd | 115:156b8234f2de | 64 | |
voltxd | 115:156b8234f2de | 65 | case COMMAND_ASSERVISSEMENT: |
voltxd | 115:156b8234f2de | 66 | receiveIndexLimit = 6; |
voltxd | 115:156b8234f2de | 67 | break; |
voltxd | 115:156b8234f2de | 68 | |
voltxd | 115:156b8234f2de | 69 | case COMMAND_PARAMETRES: |
voltxd | 115:156b8234f2de | 70 | receiveIndexLimit = 8; |
voltxd | 115:156b8234f2de | 71 | break; |
voltxd | 115:156b8234f2de | 72 | |
voltxd | 115:156b8234f2de | 73 | default: |
voltxd | 115:156b8234f2de | 74 | receiveState = STATE_START_OF_FRAME; |
voltxd | 115:156b8234f2de | 75 | break; |
voltxd | 110:a6d1d3525014 | 76 | } |
voltxd | 110:a6d1d3525014 | 77 | break; |
voltxd | 110:a6d1d3525014 | 78 | |
voltxd | 115:156b8234f2de | 79 | case STATE_PAYLOAD: |
voltxd | 115:156b8234f2de | 80 | receivedPayload[receiveIndex++] = c; |
voltxd | 115:156b8234f2de | 81 | if (receiveIndex >= receiveIndexLimit) |
voltxd | 115:156b8234f2de | 82 | receiveState = STATE_CHECKSUM; |
voltxd | 115:156b8234f2de | 83 | break; |
voltxd | 115:156b8234f2de | 84 | |
voltxd | 110:a6d1d3525014 | 85 | case STATE_CHECKSUM: |
voltxd | 110:a6d1d3525014 | 86 | //Checksum |
voltxd | 115:156b8234f2de | 87 | if (c == calculateChecksum(receivedCommand, receivedPayload, receiveIndexLimit)) |
voltxd | 110:a6d1d3525014 | 88 | { |
voltxd | 111:f11575e7c79b | 89 | //The frame is correct, we can use the values retrieved. |
voltxd | 115:156b8234f2de | 90 | for (int i = 0; i < receiveIndexLimit; i++) |
voltxd | 115:156b8234f2de | 91 | verifiedPayload[i] = receivedPayload[i]; |
voltxd | 115:156b8234f2de | 92 | verifiedIndexLimit = receiveIndexLimit; |
voltxd | 115:156b8234f2de | 93 | verifiedCommand = receivedCommand; |
voltxd | 110:a6d1d3525014 | 94 | newDataAvailable = 1; |
voltxd | 110:a6d1d3525014 | 95 | } |
voltxd | 110:a6d1d3525014 | 96 | receiveState = STATE_START_OF_FRAME; |
voltxd | 110:a6d1d3525014 | 97 | break; |
voltxd | 110:a6d1d3525014 | 98 | |
voltxd | 110:a6d1d3525014 | 99 | default: |
voltxd | 110:a6d1d3525014 | 100 | receiveState = STATE_START_OF_FRAME; |
voltxd | 110:a6d1d3525014 | 101 | break; |
voltxd | 110:a6d1d3525014 | 102 | } |
voltxd | 110:a6d1d3525014 | 103 | } |
voltxd | 110:a6d1d3525014 | 104 | |
voltxd | 111:f11575e7c79b | 105 | //Return the values decoded |
voltxd | 115:156b8234f2de | 106 | char getVerifiedPayload(char *payloadOutput) |
voltxd | 110:a6d1d3525014 | 107 | { |
voltxd | 115:156b8234f2de | 108 | for (int i = 0; i < verifiedIndexLimit; i++) |
voltxd | 115:156b8234f2de | 109 | payloadOutput[i] = verifiedPayload[i]; |
voltxd | 110:a6d1d3525014 | 110 | newDataAvailable = 0; |
voltxd | 115:156b8234f2de | 111 | return verifiedCommand; |
voltxd | 110:a6d1d3525014 | 112 | } |
voltxd | 110:a6d1d3525014 | 113 | |
voltxd | 111:f11575e7c79b | 114 | //Return a value telling if new informations are available. |
voltxd | 110:a6d1d3525014 | 115 | char isDataAvailable() |
voltxd | 110:a6d1d3525014 | 116 | { |
voltxd | 110:a6d1d3525014 | 117 | return newDataAvailable; |
voltxd | 110:a6d1d3525014 | 118 | } |