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https://www.mediafire.com/file/sjhxgn70gxshilg/protocol_spi_pwm.png/file
protocol.cpp@110:a6d1d3525014, 2022-04-07 (annotated)
- Committer:
- voltxd
- Date:
- Thu Apr 07 12:13:04 2022 +0000
- Revision:
- 110:a6d1d3525014
- Child:
- 111:f11575e7c79b
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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 | 110:a6d1d3525014 | 5 | char calculateChecksum(uint32_t propulsion, uint32_t direction) |
voltxd | 110:a6d1d3525014 | 6 | { |
voltxd | 110:a6d1d3525014 | 7 | char checksum = 0xff; |
voltxd | 110:a6d1d3525014 | 8 | checksum ^= propulsion >> 8; |
voltxd | 110:a6d1d3525014 | 9 | checksum ^= propulsion & (0b11111111); |
voltxd | 110:a6d1d3525014 | 10 | checksum ^= direction >> 8; |
voltxd | 110:a6d1d3525014 | 11 | checksum ^= direction & (0b11111111); |
voltxd | 110:a6d1d3525014 | 12 | |
voltxd | 110:a6d1d3525014 | 13 | return checksum; |
voltxd | 110:a6d1d3525014 | 14 | } |
voltxd | 110:a6d1d3525014 | 15 | |
voltxd | 110:a6d1d3525014 | 16 | char receiveState = STATE_START_OF_FRAME; |
voltxd | 110:a6d1d3525014 | 17 | char receiveIndex = 0; |
voltxd | 110:a6d1d3525014 | 18 | uint32_t receivedPropulsion; |
voltxd | 110:a6d1d3525014 | 19 | uint32_t receivedDirection; |
voltxd | 110:a6d1d3525014 | 20 | |
voltxd | 110:a6d1d3525014 | 21 | uint32_t verifiedPropulsion = 1500; |
voltxd | 110:a6d1d3525014 | 22 | uint32_t verifiedDirection = 1150; |
voltxd | 110:a6d1d3525014 | 23 | |
voltxd | 110:a6d1d3525014 | 24 | void decodeMessage(char c) |
voltxd | 110:a6d1d3525014 | 25 | { |
voltxd | 110:a6d1d3525014 | 26 | switch(receiveState) |
voltxd | 110:a6d1d3525014 | 27 | { |
voltxd | 110:a6d1d3525014 | 28 | case STATE_START_OF_FRAME: |
voltxd | 110:a6d1d3525014 | 29 | //Checking if we received the start Byte |
voltxd | 110:a6d1d3525014 | 30 | if (c == 0xff) |
voltxd | 110:a6d1d3525014 | 31 | { |
voltxd | 110:a6d1d3525014 | 32 | receiveState = STATE_PROPULSION; |
voltxd | 110:a6d1d3525014 | 33 | receiveIndex = 0; |
voltxd | 110:a6d1d3525014 | 34 | } |
voltxd | 110:a6d1d3525014 | 35 | break; |
voltxd | 110:a6d1d3525014 | 36 | |
voltxd | 110:a6d1d3525014 | 37 | case STATE_PROPULSION: |
voltxd | 110:a6d1d3525014 | 38 | //Retrieving the propulsion PWM bytes (1. MSB; 2. LSB) |
voltxd | 110:a6d1d3525014 | 39 | if (receiveIndex++ == 0) |
voltxd | 110:a6d1d3525014 | 40 | receivedPropulsion = c << 8; |
voltxd | 110:a6d1d3525014 | 41 | else |
voltxd | 110:a6d1d3525014 | 42 | { |
voltxd | 110:a6d1d3525014 | 43 | receivedPropulsion += c; |
voltxd | 110:a6d1d3525014 | 44 | receiveState = STATE_DIRECTION; |
voltxd | 110:a6d1d3525014 | 45 | receiveIndex = 0; |
voltxd | 110:a6d1d3525014 | 46 | } |
voltxd | 110:a6d1d3525014 | 47 | break; |
voltxd | 110:a6d1d3525014 | 48 | |
voltxd | 110:a6d1d3525014 | 49 | case STATE_DIRECTION: |
voltxd | 110:a6d1d3525014 | 50 | //Retrieving the direction PWM bytes (1. MSB; 2. LSB) |
voltxd | 110:a6d1d3525014 | 51 | if (receiveIndex++ == 0) |
voltxd | 110:a6d1d3525014 | 52 | receivedDirection = c << 8; |
voltxd | 110:a6d1d3525014 | 53 | else |
voltxd | 110:a6d1d3525014 | 54 | { |
voltxd | 110:a6d1d3525014 | 55 | receivedDirection += c; |
voltxd | 110:a6d1d3525014 | 56 | receiveState = STATE_CHECKSUM; |
voltxd | 110:a6d1d3525014 | 57 | } |
voltxd | 110:a6d1d3525014 | 58 | break; |
voltxd | 110:a6d1d3525014 | 59 | |
voltxd | 110:a6d1d3525014 | 60 | case STATE_CHECKSUM: |
voltxd | 110:a6d1d3525014 | 61 | //Checksum |
voltxd | 110:a6d1d3525014 | 62 | if (c == calculateChecksum(receivedPropulsion, receivedDirection)) |
voltxd | 110:a6d1d3525014 | 63 | { |
voltxd | 110:a6d1d3525014 | 64 | //Le message recu est correct, on peut exploiter ses données |
voltxd | 110:a6d1d3525014 | 65 | verifiedPropulsion = receivedPropulsion; |
voltxd | 110:a6d1d3525014 | 66 | verifiedDirection = receivedDirection; |
voltxd | 110:a6d1d3525014 | 67 | newDataAvailable = 1; |
voltxd | 110:a6d1d3525014 | 68 | } |
voltxd | 110:a6d1d3525014 | 69 | receiveState = STATE_START_OF_FRAME; |
voltxd | 110:a6d1d3525014 | 70 | break; |
voltxd | 110:a6d1d3525014 | 71 | |
voltxd | 110:a6d1d3525014 | 72 | default: |
voltxd | 110:a6d1d3525014 | 73 | receiveState = STATE_START_OF_FRAME; |
voltxd | 110:a6d1d3525014 | 74 | break; |
voltxd | 110:a6d1d3525014 | 75 | } |
voltxd | 110:a6d1d3525014 | 76 | } |
voltxd | 110:a6d1d3525014 | 77 | |
voltxd | 110:a6d1d3525014 | 78 | void getVerifiedPWMValues(uint32_t *pwmPropulsion, uint32_t *pwmDirection) |
voltxd | 110:a6d1d3525014 | 79 | { |
voltxd | 110:a6d1d3525014 | 80 | *pwmPropulsion = verifiedPropulsion; |
voltxd | 110:a6d1d3525014 | 81 | *pwmDirection = verifiedDirection; |
voltxd | 110:a6d1d3525014 | 82 | newDataAvailable = 0; |
voltxd | 110:a6d1d3525014 | 83 | } |
voltxd | 110:a6d1d3525014 | 84 | |
voltxd | 110:a6d1d3525014 | 85 | char isDataAvailable() |
voltxd | 110:a6d1d3525014 | 86 | { |
voltxd | 110:a6d1d3525014 | 87 | return newDataAvailable; |
voltxd | 110:a6d1d3525014 | 88 | } |