PIC: ADXL345

ADXL345 é um acelerômetro de 3-eixos com alta resolução (13-bit) de medição de até ± 16 g e comunica-se via SPI( 4 ou 3 fios ) ou I2C.

O ADXL345 é bem adequado para aplicações em dispositivos móveis. Ele mede a aceleração estática da gravidade em aplicações tilt-sensing , bem como a aceleração dinâmica resultante do movimento ou choque. Sua alta resolução (3,9 mg / LSB) permite a medição de inclinação menos do que 1.0 °.

PINOS:

VCC	3.3V
GND	GND
SCL	I2C/SPI Clock
SDA	I2C Data/ SPI Data Input/ SPI Data InOut
SDO	SPI Data Output
INT1	Interrupção 1
INT2	Interrupção 2
CS	Chip Select

BIBLIOTECA:

MikroC PRO PIC

#include <Built_in.h>

#define DEVID    0x00 //Device ID 
#define THRESH_TAP   0x1D //Tap threshold 
#define OFSX    0x1E //X-axis offset 
#define OFSY    0x1F //Y-axis offset
#define OFSZ   0x20 //Z-axis offset
#define DUR    0x21 //Tap duration 
#define LATENT   0x22 //Tap latency  
#define WINDOW   0x23 //Tap window 
#define THRESH_ACT   0x24 //Activity threshold 
#define THRESH_INACT  0x25 //Inactivity threshold 
#define TIME_INACT   0x26 //Inactivity time 
#define ACT_INACT_CTL  0x27 //Axis enable control for activity and inactivity detection 
#define THRESH_FF  0x28 //Free-fall threshold 
#define TIME_FF   0x29 //Free-fall time 
#define TAP_AXES   0x2A //Axis control for single tap/double tap 
#define ACT_TAP_STATUS  0x2B //Source of single tap/double tap 
#define BW_RATE   0x2C //Data rate and power mode control 
#define POWER_CTL   0x2D //Power-saving features control 
#define INT_ENABLE   0x2E //Interrupt enable control 
#define INT_MAP   0x2F //Interrupt mapping control 
#define INT_SOURCE   0x30 //Source of interrupts 
#define DATA_FORMAT  0x31 //Data format control 
#define DATAX0    0x32 //X-Axis Data 0 //Hi
#define DATAX1    0x33 //X-Axis Data 1 //Low
#define DATAY0    0x34 //Y-Axis Data 0 
#define DATAY1    0x35 //Y-Axis Data 1 
#define DATAZ0    0x36 //Z-Axis Data 0 
#define DATAZ1    0x37 //Z-Axis Data 1 
#define FIFO_CTL   0x38 //FIFO control 
#define FIFO_STATUS  0x39 //FIFO status 

#define ADXL345_SDO SoftSpi_SDO
#define ADXL345_CLK SoftSpi_CLK
#define ADXL345_SDI SoftSpi_SDI 
#define ADXL345_SDO_Direction SoftSpi_SDO_Direction
#define ADXL345_CLK_Direction SoftSpi_CLK_Direction
#define ADXL345_SDI_Direction SoftSpi_SDI_Direction 


typedef struct
{
 signed int X;
 signed int Y;
 signed int Z;
}ADXL345;

static void ADXL345_Write( char addr, char value )
{
 ADXL345_CS = 0;
 Soft_SPI_Write( addr | 0x80 );
 Soft_SPI_Write( value );
 ADXL345_CS = 1;
}

static void ADXL345_Rd( char addr, char len, char *outData )
{
char i;
 addr |= 0x80;
 if( len > 1) addr |= 0x40;
 
 ADXL345_CS = 0;
 Soft_SPI_Write( addr );
 for( i=0; i < len; i++ )
 {
    outData[i] = Soft_SPI_Read( 0x00 );
 }
 ADXL345_CS = 1; 
}

void ADXL345_Init()
{
 ADXL345_CS_Direction = 0;
 ADXL345_CS = 1;
 
 ADXL345_Write( POWER_CTL, 0x00 ); // Modo Inicial em StandBy
 ADXL345_Write( DATA_FORMAT, 0x0B );// Full resolution, +/-16g, 4mg/LSB. SPI 4-Wire
 ADXL345_Write( BW_RATE, 0x0F); // Buffer Speed - 3200Hz
 ADXL345_Write( POWER_CTL, 0x08); // Measurement mode.
}

void ADXL345_Read( ADXL345 *Accel )
{
char dat[6];
 ADXL345_Rd( DATAX0, 6, &dat );
 Accel->X = ( dat[0] << 8 ) | dat[1];
 Accel->Y = ( dat[2] << 8 ) | dat[3];
 Accel->Z = ( dat[4] << 8 ) | dat[5];
}

EXEMPLO:

//Habilitar as seguintes bibliotecas:
// - Soft_SPI
// - Uart
// - Conversions e C_String

sbit ADXL345_CS at  RB4_Bit;
sbit ADXL345_SDO at RB5_Bit;
sbit ADXL345_CLK at RB6_Bit;
sbit ADXL345_SDI at RB7_Bit;
sbit ADXL345_CS_Direction at TRISB4_Bit;
sbit ADXL345_SDO_Direction at TRISB5_Bit;
sbit ADXL345_CLK_Direction at TRISB6_Bit;
sbit ADXL345_SDI_Direction at TRISB7_Bit;

//Copie e cole a biblioteca aqui

ADXL345 Accel;

char out[8];

void main()
{
    Soft_SPI_Init();
    ADXL345_Init();
    UART1_Init(9600);
    
    while(1)
    {
            ADXL345_Read( &Accel );
            
            Uart1_Write_Text( "X: " );
            IntToStr( Accel.X, out );
            Uart1_Write_Text( out );
            Uart1_Write( 13 );
            Uart1_Write( 10 );
            
            Uart1_Write_Text( "Y: " );
            IntToStr( Accel.Y, out );
            Uart1_Write_Text( out );
            Uart1_Write( 13 );
            Uart1_Write( 10 );
            
            Uart1_Write_Text( "Z: " );
            IntToStr( Accel.Z, out );
            Uart1_Write_Text( out );
            Uart1_Write( 13 );
            Uart1_Write( 10 );
            
            Delay_ms( 500 );
    }
}