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basic HMC5883L magnometer sample

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Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Brendan Le Foll
2014-04-22 15:31:28 +01:00
parent ac131e1e17
commit f011102ce6
3 changed files with 96 additions and 16 deletions
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4
examples/CMakeLists.txt
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@@ -1,9 +1,9 @@
add_executable (readi2c readi2c.cpp)
add_executable (i2c_HMC5883L i2c_HMC5883L.cpp)
add_executable (hellomaa hellomaa.cpp)
add_executable (cycle-pwm3 cycle-pwm3.cpp)
include_directories(${PROJECT_SOURCE_DIR}/api ${PROJECT_SOURCE_DIR}/include)
target_link_libraries (hellomaa maa)
target_link_libraries (readi2c maa)
target_link_libraries (i2c_HMC5883L maa)
target_link_libraries (cycle-pwm3 maa)

94
examples/i2c_HMC5883L.cpp Normal file
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@@ -0,0 +1,94 @@
#include "maa.h"
#include "math.h"
#define MAX_BUFFER_LENGTH 6
#define HMC5883L_I2C_ADDR 0x1E
//configuration registers
#define HMC5883L_CONF_REG_A 0x00
#define HMC5883L_CONF_REG_B 0x01
//mode register
#define HMC5883L_MODE_REG 0x02
//data register
#define HMC5883L_X_MSB_REG 0
#define HMC5883L_X_LSB_REG 1
#define HMC5883L_Z_MSB_REG 2
#define HMC5883L_Z_LSB_REG 3
#define HMC5883L_Y_MSB_REG 4
#define HMC5883L_Y_LSB_REG 5
#define DATA_REG_SIZE 6
//status register
#define HMC5883L_STATUS_REG 0x09
//ID registers
#define HMC5883L_ID_A_REG 0x0A
#define HMC5883L_ID_B_REG 0x0B
#define HMC5883L_ID_C_REG 0x0C
#define HMC5883L_CONT_MODE 0x00
#define HMC5883L_DATA_REG 0x03
//scales
#define GA_0_88_REG 0x00 << 5
#define GA_1_3_REG 0x01 << 5
#define GA_1_9_REG 0x02 << 5
#define GA_2_5_REG 0x03 << 5
#define GA_4_0_REG 0x04 << 5
#define GA_4_7_REG 0x05 << 5
#define GA_5_6_REG 0x06 << 5
#define GA_8_1_REG 0x07 << 5
//digital resolutions
#define SCALE_0_73_MG 0.73
#define SCALE_0_92_MG 0.92
#define SCALE_1_22_MG 1.22
#define SCALE_1_52_MG 1.52
#define SCALE_2_27_MG 2.27
#define SCALE_2_56_MG 2.56
#define SCALE_3_03_MG 3.03
#define SCALE_4_35_MG 4.35
int
main ()
{
float direction = 0;
int16_t x = 0, y = 0, z = 0;
char rx_tx_buf[MAX_BUFFER_LENGTH];
maa::I2CSlave i2c(26, 27);
i2c.address(HMC5883L_I2C_ADDR);
rx_tx_buf[0] = HMC5883L_CONF_REG_B;
rx_tx_buf[1] = GA_1_3_REG;
i2c.write(rx_tx_buf, 2);
i2c.address(HMC5883L_I2C_ADDR);
rx_tx_buf[0] = HMC5883L_MODE_REG;
rx_tx_buf[1] = HMC5883L_CONT_MODE;
i2c.write(rx_tx_buf, 2);
for(;;) {
i2c.address(HMC5883L_I2C_ADDR);
i2c.write(HMC5883L_DATA_REG);
i2c.address(HMC5883L_I2C_ADDR);
i2c.read(rx_tx_buf, DATA_REG_SIZE);
x = (rx_tx_buf[HMC5883L_X_MSB_REG] << 8 ) | rx_tx_buf[HMC5883L_X_LSB_REG] ;
z = (rx_tx_buf[HMC5883L_Z_MSB_REG] << 8 ) | rx_tx_buf[HMC5883L_Z_LSB_REG] ;
y = (rx_tx_buf[HMC5883L_Y_MSB_REG] << 8 ) | rx_tx_buf[HMC5883L_Y_LSB_REG] ;
//scale and calculate direction
direction = atan2(y * SCALE_0_92_MG, x * SCALE_0_92_MG);
//check if the signs are reversed
if (direction < 0)
direction += 2 * M_PI;
printf("Compass scaled data x : %f, y : %f, z : %f\n", x * SCALE_0_92_MG, y * SCALE_0_92_MG, z * SCALE_0_92_MG) ;
printf("Heading : %f\n", direction * 180/M_PI) ;
}
}

14
examples/readi2c.cpp
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@@ -1,14 +0,0 @@
#include "maa.h"
int
main ()
{
maa::I2CSlave i2c(26, 27);
int addr = 0x62;
i2c.address(addr);
char data[2];
int ret = i2c.read(data, 2);
return ret;
}