我正在使用将 Arduino 库转换为MSP430库的 Energia库。我将陀螺仪连接到Launchpad并使用所需的上拉电阻构建电路。以下是 Sparkfun 陀螺仪的示例代码：
//The Wire library is used for I²C communication
#include <Wire.h>
//This is a list of registers in the ITG-3200. Registers are parameters that
//determine how the sensor will behave, or they can hold data that represent
//the sensors current status.
//To learn more about the registers on the ITG-3200, download and read the datasheet.
char WHO_AM_I = 0x00;
char SMPLRT_DIV= 0x15;
char DLPF_FS = 0x16;
char GYRO_XOUT_H = 0x1D;
char GYRO_XOUT_L = 0x1E;
char GYRO_YOUT_H = 0x1F;
char GYRO_YOUT_L = 0x20;
char GYRO_ZOUT_H = 0x21;
char GYRO_ZOUT_L = 0x22;
//This is a list of settings that can be loaded into the registers.
//DLPF, Full Scale Register Bits
//FS_SEL must be set to 3 for proper operation
//Set DLPF_CFG to 3 for 1kHz Fint and 42 Hz low pass Filter
char DLPF_CFG_0 = 1<<0;
char DLPF_CFG_1 = 1<<1;
char DLPF_CFG_2 = 1<<2;
char DLPF_FS_SEL_0 = 1<<3;
char DLPF_FS_SEL_1 = 1<<4;
//I²C devices each have an address. The address is defined in the datasheet for the
//device. The ITG-3200 breakout board can have different address depending on how
//the jumper on top of the board is configured. By default, the jumper is connected to
//the VDD pin. When the jumper is connected to the VDD pin the I²C address
//is 0x69.
char itgAddress = 0x69;
//In the setup section of the sketch the serial port will be configured, the I²C
//communication will be initialized, and the ITG-3200 will be configured.
void setup()
{
//Create a serial connection using a 9600 bit/s baud rate.
Serial.begin(9600);
//Initialize the I²C communication. This will set the Arduino up as the 'Master' device.
Wire.begin();
//Read the WHO_AM_I register and print the result
char id=4;
id = itgRead(itgAddress, 0x00);
Serial.print("ID: ");
Serial.println(id, HEX);
//Configure the gyroscope
//Set the gyroscope scale for the outputs to +/-2000 degrees per second
//itgWrite(itgAddress, DLPF_FS, (DLPF_FS_SEL_0|DLPF_FS_SEL_1|DLPF_CFG_0));
//Set the sample rate to 100 Hz
//itgWrite(itgAddress, SMPLRT_DIV, 9);
}
//The loop section of the sketch will read the X,Y and Z output rates from the gyroscope and
//output them in the Serial Terminal
void loop()
{
//Create variables to hold the output rates.
//int xRate, yRate, zRate;
//Read the x,y and z output rates from the gyroscope.
// xRate = readX();
// yRate = readY();
// zRate = readZ();
//Print the output rates to the terminal, seperated by a TAB character.
// Serial.print(xRate);
// Serial.print('\t');
// Serial.print(yRate);
// Serial.print('\t');
// Serial.println(zRate);
//Wait 10 ms before reading the values again. (Remember, the output rate was set
//to 100 Hz and one reading per 10 ms = 100 Hz.)
char id = 4;
id = itgRead(itgAddress, 0x00);
Serial.print("ID: ");
Serial.println(id, HEX);
delay(1000);
}
//This function will write a value to a register on the itg-3200.
//
//Parameters:
// char address: The I²C address of the sensor. For the ITG-3200 breakout the address is 0x69.
// char registerAddress: The address of the register on the sensor that should be written to.
// char data: The value to be written to the specified register.
void itgWrite(char address, char registerAddress, char data)
{
//Initiate a communication sequence with the desired I²C device
Wire.beginTransmission(address);
//Tell the I²C address which register we are writing to
Wire.write(registerAddress);
//Send the value to write to the specified register
Wire.write(data);
//End the communication sequence
Wire.endTransmission();
}
//This function will read the data from a specified register on the ITG-3200 and return the value.
//Parameters:
// char address: The I²C address of the sensor. For the ITG-3200 breakout the address is 0x69.
// char registerAddress: The address of the register on the sensor that should be read
//Return:
// unsigned char: The value currently residing in the specified register
unsigned char itgRead(char address, char registerAddress)
{
//This variable will hold the contents read from the I²C device.
unsigned char data = 5;
//Send the register address to be read.
Wire.beginTransmission(address);
//Send the Register Address
Wire.write(registerAddress);
//End the communication sequence.
Wire.endTransmission();
//Ask the I²C device for data
//Wire.beginTransmission(address);
Wire.requestFrom(address, 1);
//Wait for a response from the I²C device
if(!Wire.available()){
//Save the data sent from the I²C device
data = Wire.read();
}
//End the communication sequence.
// Wire.endTransmission();
//Return the data read during the operation
return data;
}
//This function is used to read the X-Axis rate of the gyroscope. The function
//returns the ADC value from the gyroscope.
//NOTE: This value is NOT in degrees per second.
//Usage: int xRate = readX();
int readX(void)
{
int data = 0;
data = itgRead(itgAddress, GYRO_XOUT_H)<<8;
data |= itgRead(itgAddress, GYRO_XOUT_L);
return data;
}
//This function is used to read the Y-Axis rate of the gyroscope. The function returns
//the ADC value from the gyroscope.
//NOTE: This value is NOT in degrees per second.
//Usage: int yRate = readY();
int readY(void)
{
int data=0;
data = itgRead(itgAddress, GYRO_YOUT_H)<<8;
data |= itgRead(itgAddress, GYRO_YOUT_L);
return data;
}
//This function is used to read the Z-axis rate of the gyroscope. The function returns
//the ADC value from the gyroscope.
//NOTE: This value is NOT in degrees per second.
//Usage: int zRate = readZ();
int readZ(void)
{
int data = 0;
data = itgRead(itgAddress, GYRO_ZOUT_H)<<8;
data |= itgRead(itgAddress, GYRO_ZOUT_L);
return data;
}
我将示波器连接到 SDA 和 SCL 总线上以测量结果是否正确。在前 8 个 SCL 周期中，SDA 总线是我所期望的，7 位从地址和 1 位读取。但是对应于来自陀螺仪的 ACK 的第 9 个 SCL 周期应该为低的 SDA 似乎是错误的。陀螺仪永远不会将 SDK 降低到低电平以确认主机。
我最近买了这个产品，所以我认为它没有问题。我猜主人从不释放 SDA 总线来检查 ACK。我在这里想念什么？