从uint8_t *到uint8_t fpermissive c ++的转换无效

Question

我发现问题已被多次询问，但在阅读了许多类似的问题后，我仍然无法理解并解决这个问题。我是一个新手编码器，我还在学习，很多天我都无法解决这个问题。

我正在使用arduino的演示代码库并尝试在c ++ Atmel Studio 7中编译它（编译我基于ATSAMD21制作的自定义板）。这是我的相关代码（删除了所有不相关的部分）：

#include <Arduino.h>
#include <Wire.h>
#include "Kalman.h" // Source: https://github.com/TKJElectronics/KalmanFilter
//Beginning of Auto generated function prototypes by Atmel Studio
uint8_t i2cWrite(uint8_t registerAddress, uint8_t data, bool sendStop);
uint8_t i2cWrite(uint8_t registerAddress, uint8_t data, uint8_t length, bool sendStop);
uint8_t i2cRead(uint8_t registerAddress, uint8_t data, uint8_t nbytes);
//End of Auto generated function prototypes by Atmel Studio

#define RESTRICT_PITCH // Comment out to restrict roll to ±90deg instead - please read: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf

Kalman kalmanX; // Create the Kalman instances
Kalman kalmanY;

/* IMU Data */
double accX, accY, accZ;
double gyroX, gyroY, gyroZ;
int16_t tempRaw;

double gyroXangle, gyroYangle; // Angle calculate using the gyro only
double compAngleX, compAngleY; // Calculated angle using a complementary filter
double kalAngleX, kalAngleY; // Calculated angle using a Kalman filter

uint32_t timer;
uint8_t i2cData[14]; // Buffer for I2C data

// TODO: Make calibration routine

#if defined(ARDUINO_SAMD_ZERO) && defined(SERIAL_PORT_USBVIRTUAL)
  // Required for Serial on Zero based boards
  #define Serial SERIAL_PORT_USBVIRTUAL
#endif

void setup() {
  Serial.begin(115200);
  Wire.begin();
  //TWBR = ((F_CPU / 400000L) - 16) / 2; // Set I2C frequency to 400kHz

  i2cData[0] = 7; // Set the sample rate to 1000Hz - 8kHz/(7+1) = 1000Hz
  i2cData[1] = 0x00; // Disable FSYNC and set 260 Hz Acc filtering, 256 Hz Gyro filtering, 8 KHz sampling
  i2cData[2] = 0x00; // Set Gyro Full Scale Range to ±250deg/s
  i2cData[3] = 0x00; // Set Accelerometer Full Scale Range to ±2g
  while (i2cWrite(0x19, *i2cData, 4, false)); // Write to all four registers at once
  while (i2cWrite(0x6B, 0x01, true)); // PLL with X axis gyroscope reference and disable sleep mode

  while (i2cRead(0x75, *i2cData, 1));
  if (i2cData[0] != 0x68) { // Read "WHO_AM_I" register
    Serial.print(F("Error reading sensor"));
    while (1);
  }

  //delay(100); // Wait for sensor to stabilize

  /* Set kalman and gyro starting angle */
  while (i2cRead(0x3B, *i2cData, 6));
  accX = (i2cData[0] << 8) | i2cData[1];
  accY = (i2cData[2] << 8) | i2cData[3];
  accZ = (i2cData[4] << 8) | i2cData[5];

  // Source: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf eq. 25 and eq. 26
  // atan2 outputs the value of -π to π (radians) - see http://en.wikipedia.org/wiki/Atan2
  // It is then converted from radians to degrees
#ifdef RESTRICT_PITCH // Eq. 25 and 26
  double roll  = atan2(accY, accZ) * RAD_TO_DEG;
  double pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
#else // Eq. 28 and 29
  double roll  = atan(accY / sqrt(accX * accX + accZ * accZ)) * RAD_TO_DEG;
  double pitch = atan2(-accX, accZ) * RAD_TO_DEG;
#endif

  kalmanX.setAngle(roll); // Set starting angle
  kalmanY.setAngle(pitch);
  gyroXangle = roll;
  gyroYangle = pitch;
  compAngleX = roll;
  compAngleY = pitch;

  timer = micros();
}

void loop() {
  /* Update all the values */
  while (i2cRead(0x3B, *i2cData, 14));
  accX = ((i2cData[0] << 8) | i2cData[1]);
  accY = ((i2cData[2] << 8) | i2cData[3]);
  accZ = ((i2cData[4] << 8) | i2cData[5]);
  tempRaw = (i2cData[6] << 8) | i2cData[7];
  gyroX = (i2cData[8] << 8) | i2cData[9];
  gyroY = (i2cData[10] << 8) | i2cData[11];
  gyroZ = (i2cData[12] << 8) | i2cData[13];

  double dt = (double)(micros() - timer) / 1000000; // Calculate delta time
  timer = micros();

  // Source: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf eq. 25 and eq. 26
  // atan2 outputs the value of -π to π (radians) - see http://en.wikipedia.org/wiki/Atan2
  // It is then converted from radians to degrees
#ifdef RESTRICT_PITCH // Eq. 25 and 26
  double roll  = atan2(accY, accZ) * RAD_TO_DEG;
  double pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
#else // Eq. 28 and 29
  double roll  = atan(accY / sqrt(accX * accX + accZ * accZ)) * RAD_TO_DEG;
  double pitch = atan2(-accX, accZ) * RAD_TO_DEG;
#endif

  double gyroXrate = gyroX / 131.0; // Convert to deg/s
  double gyroYrate = gyroY / 131.0; // Convert to deg/s

#ifdef RESTRICT_PITCH
  // This fixes the transition problem when the accelerometer angle jumps between -180 and 180 degrees
  if ((roll < -90 && kalAngleX > 90) || (roll > 90 && kalAngleX < -90)) {
    kalmanX.setAngle(roll);
    compAngleX = roll;
    kalAngleX = roll;
    gyroXangle = roll;
  } else
    kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter

  if (abs(kalAngleX) > 90)
    gyroYrate = -gyroYrate; // Invert rate, so it fits the restriced accelerometer reading
  kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt);
#else
  // This fixes the transition problem when the accelerometer angle jumps between -180 and 180 degrees
  if ((pitch < -90 && kalAngleY > 90) || (pitch > 90 && kalAngleY < -90)) {
    kalmanY.setAngle(pitch);
    compAngleY = pitch;
    kalAngleY = pitch;
    gyroYangle = pitch;
  } else
    kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt); // Calculate the angle using a Kalman filter

  if (abs(kalAngleY) > 90)
    gyroXrate = -gyroXrate; // Invert rate, so it fits the restriced accelerometer reading
  kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter
#endif

  gyroXangle += gyroXrate * dt; // Calculate gyro angle without any filter
  gyroYangle += gyroYrate * dt;
  //gyroXangle += kalmanX.getRate() * dt; // Calculate gyro angle using the unbiased rate
  //gyroYangle += kalmanY.getRate() * dt;

  compAngleX = 0.93 * (compAngleX + gyroXrate * dt) + 0.07 * roll; // Calculate the angle using a Complimentary filter
  compAngleY = 0.93 * (compAngleY + gyroYrate * dt) + 0.07 * pitch;

  // Reset the gyro angle when it has drifted too much
  if (gyroXangle < -180 || gyroXangle > 180)
    gyroXangle = kalAngleX;
  if (gyroYangle < -180 || gyroYangle > 180)
    gyroYangle = kalAngleY;

uint32_t time = millis();

  /* Print Data */
#if 1 // Set to 1 to activate
  Serial.print(accX); Serial.print("\t");
  Serial.print(accY); Serial.print("\t");
  Serial.print(accZ); Serial.print("\t");

  Serial.print(gyroX); Serial.print("\t");
  Serial.print(gyroY); Serial.print("\t");
  Serial.print(gyroZ); Serial.print("\t");

  Serial.print(time); Serial.print("\t");

  Serial.print("\t");
#endif
#if 0
  Serial.print(roll); Serial.print("\t");
  Serial.print(gyroXangle); Serial.print("\t");
  Serial.print(compAngleX); Serial.print("\t");
  Serial.print(kalAngleX); Serial.print("\t");

  Serial.print("\t");

  Serial.print(pitch); Serial.print("\t");
  Serial.print(gyroYangle); Serial.print("\t");
  Serial.print(compAngleY); Serial.print("\t");
  Serial.print(kalAngleY); Serial.print("\t");
#endif
#if 1 // Set to 1 to print the temperature
  Serial.print("\t");

  double temperature = (double)tempRaw / 340.0 + 36.53;
  Serial.print(temperature); Serial.print("\t");
#endif

  Serial.print("\r\n");
  //delay(2);
}    

const uint8_t IMUAddress = 0x68; // AD0 is logic low on the PCB
const uint16_t I2C_TIMEOUT = 1000; // Used to check for errors in I2C communication

uint8_t i2cWrite(uint8_t registerAddress, uint8_t data, bool sendStop) {
  return i2cWrite(registerAddress, &data, 1, sendStop); // INVALID CONVERSION ERROR HERE
}

uint8_t i2cWrite(uint8_t registerAddress, uint8_t *data, uint8_t length, bool sendStop) {
  Wire.beginTransmission(IMUAddress);
  Wire.write(registerAddress);
  Wire.write(data, length);
  uint8_t rcode = Wire.endTransmission(sendStop); // Returns 0 on success
  if (rcode) {
    Serial.print(F("i2cWrite failed: "));
    Serial.println(rcode);
  }
  return rcode; // See: http://arduino.cc/en/Reference/WireEndTransmission
}

uint8_t i2cRead(uint8_t registerAddress, uint8_t *data, uint8_t nbytes) {
  uint32_t timeOutTimer;
  Wire.beginTransmission(IMUAddress);
  Wire.write(registerAddress);
  uint8_t rcode = Wire.endTransmission(false); // Don't release the bus
  if (rcode) {
    Serial.print(F("i2cRead failed: "));
    Serial.println(rcode);
    return rcode; // See: http://arduino.cc/en/Reference/WireEndTransmission
  }
  Wire.requestFrom(IMUAddress, nbytes, (uint8_t)true); // Send a repeated start and then release the bus after reading
  for (uint8_t i = 0; i < nbytes; i++) {
    if (Wire.available())
      data[i] = Wire.read();
    else {
      timeOutTimer = micros();
      while (((micros() - timeOutTimer) < I2C_TIMEOUT) && !Wire.available());
      if (Wire.available())
        data[i] = Wire.read();
      else {
        Serial.println(F("i2cRead timeout"));
        return 5; // This error value is not already taken by endTransmission
      }
    }
  }
  return 0; // Success
}

以上代码在第195行Col 54：

的i2cWrite函数中给出了错误

来自＆＃39; uint8_t * {aka unsigned char *}＆＃39;的无效转换to＆＃39; uint8_t {aka unsigned char}＆＃39; -fpermissive

请注意，我首先修改了上面的代码，并在第43,46,55,83行的i2cWrite / i2cRead数组中添加了一个*星号。如果我不添加那些，那么所有这些行上都会出现相同的错误好。由于原始代码没有那些*引用，也许我不应该添加这些指针......？

我正在尝试学习指针和参考资料，但却苦苦挣扎。对于我的生活，我无法理解如何解决这个错误。我试过各种各样的＆amp; *但是对于我的生活，我无法理解并纠正这个问题。我似乎无法理解我的代码如何/在何处尝试将uint8_t *分配给uint8_t。

对于其他主题，我是否需要为这些变量中的任何变量强制转换或使用volatile或const？我不这么认为，但我又是一个初学者。

我非常感谢任何人指出我正确的方向或帮助我理解解决方案。在Arduino中，我可以编译并运行此代码，但不能在Atmel Studio中编译和运行。非常感谢任何帮助。

编辑：我已更新代码并删除了评论，以便错误和行号与我的帖子相符。对#s。

行的混淆表示歉意

Answer 1

您需要在调用之前声明该函数。

在i2cWrite的定义中，它无法看到接收指针作为参数的重载声明。因此，编译器假设您以递归方式调用该函数，其中的参数类型错误。

Answer 2

这是一个问题：

uint8_t i2cWrite(uint8_t registerAddress, uint8_t data, bool sendStop) {
  return i2cWrite(registerAddress, &data, 1, sendStop); // Returns 0 on success
}

如第一行所示，i2cWrite有3个参数：uint8_t，uint8_t和bool。但是你用4个参数调用它：uint8_t，uint8_t *，int，bool。

然后在此之后声明另一个名为i2cWrite的函数，它接受4个参数。这是不允许的。

很难说，但我猜你希望这些函数有不同的名称，3参数和4参数。

Answer 3

感谢两个答案。解决方案只是我的功能原型在一开始略有不同。第二个i2cWrite声明缺少derefernce *星号。这修复了它。