commit 39f76cb62b32da2ea8d7a7154e1b2854dbf792ab
Author: 0xFEEDC0DE64 <daniel@brunner.ninja>
Date:   Tue May 19 10:59:53 2020 +0200

    Added protocol.h

diff --git a/protocol.h b/protocol.h
new file mode 100644
index 0000000..35cde1e
--- /dev/null
+++ b/protocol.h
@@ -0,0 +1,122 @@
+#pragma once
+
+#include <stdint.h>
+
+namespace {
+
+enum class ControlType : uint8_t {
+    Commutation,
+    Sinusoidal,
+    FieldOrientedControl
+};
+
+enum class ControlMode : uint8_t {
+    OpenMode,
+    Voltage,
+    Speed, // Only with FieldOrientedControl
+    Torque // Only with FieldOrientedControl
+};
+
+struct MotorState {
+    bool enable = false;
+    int16_t pwm = 0;
+    ControlType ctrlTyp = ControlType::FieldOrientedControl;
+    ControlMode ctrlMod = ControlMode::OpenMode;
+    int16_t iMotMax = 15;                  // [A] Maximum motor current limit
+    int16_t iDcMax = 17;                   // [A] Maximum DC Link current limit (This is the final current protection. Above this value, current chopping is applied. To avoid this make sure that I_DC_MAX = I_MOT_MAX + 2A)
+    int16_t nMotMax = 1000;                // [rpm] Maximum motor speed limit
+    int16_t fieldWeakMax = 10;             // [A] Maximum Field Weakening D axis current (only for FOC). Higher current results in higher maximum speed.
+    int16_t phaseAdvMax = 40;              // [deg] Maximum Phase Advance angle (only for SIN). Higher angle results in higher maximum speed.
+};
+
+uint16_t calculateChecksum(MotorState state) {
+    return
+        uint16_t(state.enable) ^
+        state.pwm ^
+        uint16_t(state.ctrlTyp) ^
+        uint16_t(state.ctrlMod) ^
+        state.iMotMax ^
+        state.iDcMax ^
+        state.nMotMax ^
+        state.fieldWeakMax ^
+        state.phaseAdvMax;
+}
+
+struct BuzzerState {
+    uint8_t freq = 0;
+    uint8_t pattern = 0;
+};
+
+uint16_t calculateChecksum(BuzzerState state) {
+    return state.freq ^ state.pattern;
+}
+
+struct Command {
+    static constexpr uint16_t VALID_HEADER = 0xAAAA;
+    static constexpr uint16_t INVALID_HEADER = 0xFFFF;
+
+    uint16_t start;
+
+    MotorState left, right;
+
+    BuzzerState buzzer;
+
+    bool poweroff = false;
+    bool led = false;
+
+    uint16_t checksum;
+};
+
+uint16_t calculateChecksum(Command command) {
+    return command.start ^
+           calculateChecksum(command.left) ^
+           calculateChecksum(command.right) ^
+           calculateChecksum(command.buzzer) ^
+           command.poweroff ^
+           command.led;
+}
+
+struct MotorFeedback {
+    int16_t   angle = 0;
+    int16_t   speed = 0;
+    uint8_t   error = 0;
+    int16_t   current = 0;
+    uint32_t  chops = 0;
+    bool      hallA = false,
+              hallB = false,
+              hallC = false;
+};
+
+uint16_t calculateChecksum(MotorFeedback feedback) {
+    return feedback.angle ^ feedback.speed ^
+           feedback.error ^ feedback.current ^
+           feedback.chops ^
+           feedback.hallA ^ feedback.hallB ^ feedback.hallC;
+}
+
+struct Feedback {
+    static constexpr uint16_t VALID_HEADER = 0xAAAA;
+    static constexpr uint16_t INVALID_HEADER = 0xFFFF;
+
+    uint16_t start;
+
+    MotorFeedback left, right;
+
+    int16_t   batVoltage = 0;
+    int16_t   boardTemp = 0;
+
+    int16_t timeoutCntSerial   = 0;
+
+    uint16_t checksum;
+};
+
+uint16_t calculateChecksum(Feedback feedback) {
+    return feedback.start ^
+           calculateChecksum(feedback.left) ^
+           calculateChecksum(feedback.right) ^
+           feedback.batVoltage ^
+           feedback.boardTemp ^
+           feedback.timeoutCntSerial;
+}
+
+}