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Dependencies: L432KC_SPI_Pey_Lal
protocol.cpp@115:156b8234f2de, 2022-05-18 (annotated)
- Committer:
- voltxd
- Date:
- Wed May 18 18:07:09 2022 +0000
- Revision:
- 115:156b8234f2de
- Parent:
- 111:f11575e7c79b
- Child:
- 116:6dfcafa00e42
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Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| voltxd | 110:a6d1d3525014 | 1 | #include "protocol.h" |
| voltxd | 110:a6d1d3525014 | 2 | |
| voltxd | 110:a6d1d3525014 | 3 | char newDataAvailable = 0; |
| voltxd | 110:a6d1d3525014 | 4 | |
| voltxd | 111:f11575e7c79b | 5 | //Bytewise XOR |
| voltxd | 115:156b8234f2de | 6 | char calculateChecksum(char command, char* payload, char payloadLength) |
| voltxd | 110:a6d1d3525014 | 7 | { |
| voltxd | 110:a6d1d3525014 | 8 | char checksum = 0xff; |
| voltxd | 115:156b8234f2de | 9 | checksum ^= command; |
| voltxd | 115:156b8234f2de | 10 | for (int i = 0; i < payloadLength; i++) |
| voltxd | 115:156b8234f2de | 11 | checksum ^= payload[i]; |
| voltxd | 110:a6d1d3525014 | 12 | return checksum; |
| voltxd | 110:a6d1d3525014 | 13 | } |
| voltxd | 110:a6d1d3525014 | 14 | |
| voltxd | 110:a6d1d3525014 | 15 | char receiveState = STATE_START_OF_FRAME; |
| voltxd | 110:a6d1d3525014 | 16 | char receiveIndex = 0; |
| voltxd | 115:156b8234f2de | 17 | char receiveIndexLimit; |
| voltxd | 115:156b8234f2de | 18 | char receivedCommand; |
| voltxd | 115:156b8234f2de | 19 | char receivedPayload[PAYLOAD_MAX_SIZE] = {0}; |
| voltxd | 110:a6d1d3525014 | 20 | |
| voltxd | 115:156b8234f2de | 21 | char verifiedPayload[PAYLOAD_MAX_SIZE] = {0}; |
| voltxd | 115:156b8234f2de | 22 | char verifiedIndexLimit; |
| voltxd | 115:156b8234f2de | 23 | char verifiedCommand; |
| voltxd | 110:a6d1d3525014 | 24 | |
| voltxd | 111:f11575e7c79b | 25 | //Decode the bytes received according to their order of reception. |
| voltxd | 110:a6d1d3525014 | 26 | void decodeMessage(char c) |
| voltxd | 110:a6d1d3525014 | 27 | { |
| voltxd | 110:a6d1d3525014 | 28 | switch(receiveState) |
| voltxd | 110:a6d1d3525014 | 29 | { |
| voltxd | 110:a6d1d3525014 | 30 | case STATE_START_OF_FRAME: |
| voltxd | 110:a6d1d3525014 | 31 | //Checking if we received the start Byte |
| voltxd | 110:a6d1d3525014 | 32 | if (c == 0xff) |
| voltxd | 110:a6d1d3525014 | 33 | { |
| voltxd | 115:156b8234f2de | 34 | receiveState = STATE_COMMAND_TYPE; |
| voltxd | 110:a6d1d3525014 | 35 | receiveIndex = 0; |
| voltxd | 110:a6d1d3525014 | 36 | } |
| voltxd | 110:a6d1d3525014 | 37 | break; |
| voltxd | 110:a6d1d3525014 | 38 | |
| voltxd | 115:156b8234f2de | 39 | case STATE_COMMAND_TYPE: |
| voltxd | 115:156b8234f2de | 40 | receivedCommand = c; |
| voltxd | 115:156b8234f2de | 41 | receiveState = STATE_PAYLOAD; |
| voltxd | 115:156b8234f2de | 42 | switch(receivedCommand) |
| voltxd | 110:a6d1d3525014 | 43 | { |
| voltxd | 115:156b8234f2de | 44 | case COMMAND_PWM: |
| voltxd | 115:156b8234f2de | 45 | receiveIndexLimit = 4; |
| voltxd | 115:156b8234f2de | 46 | break; |
| voltxd | 115:156b8234f2de | 47 | |
| voltxd | 115:156b8234f2de | 48 | case COMMAND_ASSERVISSEMENT: |
| voltxd | 115:156b8234f2de | 49 | receiveIndexLimit = 6; |
| voltxd | 115:156b8234f2de | 50 | break; |
| voltxd | 115:156b8234f2de | 51 | |
| voltxd | 115:156b8234f2de | 52 | case COMMAND_PARAMETRES: |
| voltxd | 115:156b8234f2de | 53 | receiveIndexLimit = 8; |
| voltxd | 115:156b8234f2de | 54 | break; |
| voltxd | 115:156b8234f2de | 55 | |
| voltxd | 115:156b8234f2de | 56 | default: |
| voltxd | 115:156b8234f2de | 57 | receiveState = STATE_START_OF_FRAME; |
| voltxd | 115:156b8234f2de | 58 | break; |
| voltxd | 110:a6d1d3525014 | 59 | } |
| voltxd | 110:a6d1d3525014 | 60 | break; |
| voltxd | 110:a6d1d3525014 | 61 | |
| voltxd | 115:156b8234f2de | 62 | case STATE_PAYLOAD: |
| voltxd | 115:156b8234f2de | 63 | receivedPayload[receiveIndex++] = c; |
| voltxd | 115:156b8234f2de | 64 | if (receiveIndex >= receiveIndexLimit) |
| voltxd | 115:156b8234f2de | 65 | receiveState = STATE_CHECKSUM; |
| voltxd | 115:156b8234f2de | 66 | break; |
| voltxd | 115:156b8234f2de | 67 | |
| voltxd | 110:a6d1d3525014 | 68 | case STATE_CHECKSUM: |
| voltxd | 110:a6d1d3525014 | 69 | //Checksum |
| voltxd | 115:156b8234f2de | 70 | if (c == calculateChecksum(receivedCommand, receivedPayload, receiveIndexLimit)) |
| voltxd | 110:a6d1d3525014 | 71 | { |
| voltxd | 111:f11575e7c79b | 72 | //The frame is correct, we can use the values retrieved. |
| voltxd | 115:156b8234f2de | 73 | for (int i = 0; i < receiveIndexLimit; i++) |
| voltxd | 115:156b8234f2de | 74 | verifiedPayload[i] = receivedPayload[i]; |
| voltxd | 115:156b8234f2de | 75 | verifiedIndexLimit = receiveIndexLimit; |
| voltxd | 115:156b8234f2de | 76 | verifiedCommand = receivedCommand; |
| voltxd | 110:a6d1d3525014 | 77 | newDataAvailable = 1; |
| voltxd | 110:a6d1d3525014 | 78 | } |
| voltxd | 110:a6d1d3525014 | 79 | receiveState = STATE_START_OF_FRAME; |
| voltxd | 110:a6d1d3525014 | 80 | break; |
| voltxd | 110:a6d1d3525014 | 81 | |
| voltxd | 110:a6d1d3525014 | 82 | default: |
| voltxd | 110:a6d1d3525014 | 83 | receiveState = STATE_START_OF_FRAME; |
| voltxd | 110:a6d1d3525014 | 84 | break; |
| voltxd | 110:a6d1d3525014 | 85 | } |
| voltxd | 110:a6d1d3525014 | 86 | } |
| voltxd | 110:a6d1d3525014 | 87 | |
| voltxd | 111:f11575e7c79b | 88 | //Return the values decoded |
| voltxd | 115:156b8234f2de | 89 | char getVerifiedPayload(char *payloadOutput) |
| voltxd | 110:a6d1d3525014 | 90 | { |
| voltxd | 115:156b8234f2de | 91 | for (int i = 0; i < verifiedIndexLimit; i++) |
| voltxd | 115:156b8234f2de | 92 | payloadOutput[i] = verifiedPayload[i]; |
| voltxd | 110:a6d1d3525014 | 93 | newDataAvailable = 0; |
| voltxd | 115:156b8234f2de | 94 | return verifiedCommand; |
| voltxd | 110:a6d1d3525014 | 95 | } |
| voltxd | 110:a6d1d3525014 | 96 | |
| voltxd | 111:f11575e7c79b | 97 | //Return a value telling if new informations are available. |
| voltxd | 110:a6d1d3525014 | 98 | char isDataAvailable() |
| voltxd | 110:a6d1d3525014 | 99 | { |
| voltxd | 110:a6d1d3525014 | 100 | return newDataAvailable; |
| voltxd | 110:a6d1d3525014 | 101 | } |