packaging: also support rpmbuild from Tizen:2.3

[contrib/mraa.git] / examples / i2c_HMC5883L.c

diff --git a/examples/i2c_HMC5883L.c b/examples/i2c_HMC5883L.c
index e474ff4..cfaac17 100644 (file)
--- a/examples/i2c_HMC5883L.c
+++ b/examples/i2c_HMC5883L.c
@@ -22,20 +22,20 @@
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-#include "maa.h"
+#include "mraa.h"
 #include "math.h"
 
 #define MAX_BUFFER_LENGTH 6
 #define HMC5883L_I2C_ADDR 0x1E
 
-//configuration registers
+// configuration registers
 #define HMC5883L_CONF_REG_A 0x00
 #define HMC5883L_CONF_REG_B 0x01
 
-//mode register
+// mode register
 #define HMC5883L_MODE_REG 0x02
 
-//data register
+// data register
 #define HMC5883L_X_MSB_REG 0
 #define HMC5883L_X_LSB_REG 1
 #define HMC5883L_Z_MSB_REG 2
@@ -44,10 +44,10 @@
 #define HMC5883L_Y_LSB_REG 5
 #define DATA_REG_SIZE 6
 
-//status register
+// status register
 #define HMC5883L_STATUS_REG 0x09
 
-//ID registers
+// ID registers
 #define HMC5883L_ID_A_REG 0x0A
 #define HMC5883L_ID_B_REG 0x0B
 #define HMC5883L_ID_C_REG 0x0C
@@ -55,7 +55,7 @@
 #define HMC5883L_CONT_MODE 0x00
 #define HMC5883L_DATA_REG 0x03
 
-//scales
+// scales
 #define GA_0_88_REG 0x00 << 5
 #define GA_1_3_REG 0x01 << 5
 #define GA_1_9_REG 0x02 << 5
@@ -65,7 +65,7 @@
 #define GA_5_6_REG 0x06 << 5
 #define GA_8_1_REG 0x07 << 5
 
-//digital resolutions
+// digital resolutions
 #define SCALE_0_73_MG 0.73
 #define SCALE_0_92_MG 0.92
 #define SCALE_1_22_MG 1.22
@@ -76,44 +76,61 @@
 #define SCALE_4_35_MG 4.35
 
 int
-main ()
+main(int argc, char** argv)
 {
+    mraa_init();
     float direction = 0;
     int16_t x = 0, y = 0, z = 0;
-    char rx_tx_buf[MAX_BUFFER_LENGTH];
+    uint8_t rx_tx_buf[MAX_BUFFER_LENGTH];
 
-    i2c_t i2c;
-    maa_i2c_init(&i2c);
+    //! [Interesting]
+    mraa_i2c_context i2c;
+    i2c = mraa_i2c_init(0);
 
-    maa_i2c_address(&i2c, HMC5883L_I2C_ADDR);
+    mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
     rx_tx_buf[0] = HMC5883L_CONF_REG_B;
     rx_tx_buf[1] = GA_1_3_REG;
-    maa_i2c_write(&i2c, rx_tx_buf, 2);
+    mraa_i2c_write(i2c, rx_tx_buf, 2);
+    //! [Interesting]
 
-    maa_i2c_address(&i2c, HMC5883L_I2C_ADDR);
+    mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
     rx_tx_buf[0] = HMC5883L_MODE_REG;
     rx_tx_buf[1] = HMC5883L_CONT_MODE;
-    maa_i2c_write(&i2c, rx_tx_buf, 2);
-
-    for(;;) {
-        maa_i2c_address(&i2c, HMC5883L_I2C_ADDR);
-        maa_i2c_write_byte(&i2c, HMC5883L_DATA_REG);
-
-        maa_i2c_address(&i2c, HMC5883L_I2C_ADDR);
-        maa_i2c_read(&i2c, 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
+    mraa_i2c_write(i2c, rx_tx_buf, 2);
+
+    for (;;) {
+#if 0
+        int i = 0;
+        //alternative, equivalent method which helps to understand exactly what
+        //the below does
+        mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
+        for (i = 0; i < DATA_REG_SIZE; i++) {
+            mraa_i2c_read_byte_data(i2c, HMC5883L_DATA_REG+i);
+        }
+#endif
+        // first 'select' the register we want to read from
+        mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
+        mraa_i2c_write_byte(i2c, HMC5883L_DATA_REG);
+
+        // then we read from that register incrementing with every read the
+        // chosen register
+        mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
+        // this call behaves very similarly to the Wire receive() call
+        mraa_i2c_read(i2c, 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
+        // 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) ;
+        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);
     }
 }