求助：恳求arduino中用IIC读取MMA8452三轴加速度模块数据的范例。
我购买了一块MMA8452三轴加速度模块，IIC界面的，没有想到搜遍整个网络均未发现基于arduino中的范例，英文的说明书又看不懂，想参考ADXL345等模块的写法，瞎忙活了三、四天都以失败告终，恳请站内哪位大哥见义勇为一下。如能在关键之处标出注释，更加感激不尽。现附上模块图片与英文说明书。
自言自语一下。 没有人愿意帮忙吗？ 来个好心人帮个忙吧。
你可以试试这个mma7455的库，看看是否可用。。。目前我只找到7455的。或者你根据datasheet，在7455基础上改改。。。http://code.google.com/p/mma-7455-arduino-library/
呵呵，老兄，我也在用这个，刚找到了代码，也测试了下，没问题。贴出来，给大家共享。
接线顺序可以参考代码里面的注释。/*
MMA8452Q Basic Example Code
Nathan Seidle
SparkFun Electronics
November 5, 2012
License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
This example code shows how to read the X/Y/Z accelerations and basic functions of the MMA5842. It leaves out
all the neat features this IC is capable of (tap, orientation, and inerrupts) and just displays X/Y/Z. See
the advanced example code to see more features.
Hardware setup:
MMA8452 Breakout ------------ Arduino
3.3V --------------------- 3.3V
SDA -------^^(330)^^------- A4
SCL -------^^(330)^^------- A5
GND ---------------------- GND
The MMA8452 is 3.3V so we recommend using 330 or 1k resistors between a 5V Arduino and the MMA8452 breakout.
The MMA8452 has built in pull-up resistors for I2C so you do not need additional pull-ups.
*/
#include <Wire.h> // Used for I2C
// The SparkFun breakout board defaults to 1, set to 0 if SA0 jumper on the bottom of the board is set
#define MMA8452_ADDRESS 0x1D// 0x1D if SA0 is high, 0x1C if low
//Define a few of the registers that we will be accessing on the MMA8452
#define OUT_X_MSB 0x01
#define XYZ_DATA_CFG0x0E
#define WHO_AM_I 0x0D
#define CTRL_REG10x2A
#define GSCALE 2 // Sets full-scale range to +/-2, 4, or 8g. Used to calc real g values.
void setup()
{
Serial.begin(9600);
Serial.println("MMA8452 Basic Example");
Wire.begin(); //Join the bus as a master
initMMA8452(); //Test and intialize the MMA8452
}
void loop()
{
int accelCount;// Stores the 12-bit signed value
readAccelData(accelCount);// Read the x/y/z adc values
// Now we'll calculate the accleration value into actual g's
float accelG;// Stores the real accel value in g's
for (int i = 0 ; i < 3 ; i++)
{
accelG = (float) accelCount / ((1<<12)/(2*GSCALE));// get actual g value, this depends on scale being set
}
// Print out values
for (int i = 0 ; i < 3 ; i++)
{
Serial.print(accelG, 4);// Print g values
Serial.print("\t");// tabs in between axes
}
Serial.println();
delay(10);// Delay here for visibility
}
void readAccelData(int *destination)
{
byte rawData;// x/y/z accel register data stored here
readRegisters(OUT_X_MSB, 6, rawData);// Read the six raw data registers into data array
// Loop to calculate 12-bit ADC and g value for each axis
for(int i = 0; i < 3 ; i++)
{
int gCount = (rawData << 8) | rawData[(i*2)+1];//Combine the two 8 bit registers into one 12-bit number
gCount >>= 4; //The registers are left align, here we right align the 12-bit integer
// If the number is negative, we have to make it so manually (no 12-bit data type)
if (rawData > 0x7F)
{
gCount = ~gCount + 1;
gCount *= -1;// Transform into negative 2's complement #
}
destination = gCount; //Record this gCount into the 3 int array
}
}
// Initialize the MMA8452 registers
// See the many application notes for more info on setting all of these registers:
// http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MMA8452Q
void initMMA8452()
{
byte c = readRegister(WHO_AM_I);// Read WHO_AM_I register
if (c == 0x2A) // WHO_AM_I should always be 0x2A
{
Serial.println("MMA8452Q is online...");
}
else
{
Serial.print("Could not connect to MMA8452Q: 0x");
Serial.println(c, HEX);
while(1) ; // Loop forever if communication doesn't happen
}
MMA8452Standby();// Must be in standby to change registers
// Set up the full scale range to 2, 4, or 8g.
byte fsr = GSCALE;
if(fsr > 8) fsr = 8; //Easy error check
fsr >>= 2; // Neat trick, see page 22. 00 = 2G, 01 = 4A, 10 = 8G
writeRegister(XYZ_DATA_CFG, fsr);
//The default data rate is 800Hz and we don't modify it in this example code
MMA8452Active();// Set to active to start reading
}
// Sets the MMA8452 to standby mode. It must be in standby to change most register settings
void MMA8452Standby()
{
byte c = readRegister(CTRL_REG1);
writeRegister(CTRL_REG1, c & ~(0x01)); //Clear the active bit to go into standby
}
// Sets the MMA8452 to active mode. Needs to be in this mode to output data
void MMA8452Active()
{
byte c = readRegister(CTRL_REG1);
writeRegister(CTRL_REG1, c | 0x01); //Set the active bit to begin detection
}
// Read bytesToRead sequentially, starting at addressToRead into the dest byte array
void readRegisters(byte addressToRead, int bytesToRead, byte * dest)
{
Wire.beginTransmission(MMA8452_ADDRESS);
Wire.write(addressToRead);
Wire.endTransmission(false); //endTransmission but keep the connection active
Wire.requestFrom(MMA8452_ADDRESS, bytesToRead); //Ask for bytes, once done, bus is released by default
while(Wire.available() < bytesToRead); //Hang out until we get the # of bytes we expect
for(int x = 0 ; x < bytesToRead ; x++)
dest = Wire.read();
}
// Read a single byte from addressToRead and return it as a byte
byte readRegister(byte addressToRead)
{
Wire.beginTransmission(MMA8452_ADDRESS);
Wire.write(addressToRead);
Wire.endTransmission(false); //endTransmission but keep the connection active
Wire.requestFrom(MMA8452_ADDRESS, 1); //Ask for 1 byte, once done, bus is released by default
while(!Wire.available()) ; //Wait for the data to come back
return Wire.read(); //Return this one byte
}
// Writes a single byte (dataToWrite) into addressToWrite
void writeRegister(byte addressToWrite, byte dataToWrite)
{
Wire.beginTransmission(MMA8452_ADDRESS);
Wire.write(addressToWrite);
Wire.write(dataToWrite);
Wire.endTransmission(); //Stop transmitting
} 我也被同样问题困扰多时！ wisepi 发表于 2013-2-15 23:05 static/image/common/back.gif
呵呵，老兄，我也在用这个，刚找到了代码，也测试了下，没问题。贴出来，给大家共享。
接线顺序可以参考代 ...
这个看起来是可以的。好人！ wisepi 发表于 2013-2-15 23:05 static/image/common/back.gif
呵呵，老兄，我也在用这个，刚找到了代码，也测试了下，没问题。贴出来，给大家共享。
接线顺序可以参考代 ...
本人菜鸟，刚好碰到有一个mma8452，sa0接了高电平，我今天试了那代码，怎么不行啊，通过串口，好像没有进入initMMA8452()函数吗，求大神解答。 这程序可以用，本人亲试，谢谢大神分享。 wisepi 发表于 2013-2-15 23:05 static/image/common/back.gif
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请问线怎么接的？ wisepi 发表于 2013-2-15 23:05 static/image/common/back.gif
**** 作者被禁止或删除 内容自动屏蔽 ****
请问你的线是怎么接的》为什么我的不行 你好，之前在网上见你用arduino与MMA8452Q通讯，我用的那个例程卡在 读who am i 不知道您当时怎么调试的呢？望能解答，谢谢
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