Diff: main.cpp

Revision:

0:fb4503358bc7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Jul 20 08:41:07 2017 +0000
@@ -0,0 +1,139 @@
+#include "mbed.h"
+#include <algorithm> // for min, max functions
+
+#define MAGN_I2C_ADDRESS (0x1E << 1)
+
+#define LSM303_REGISTER_MAG_OUT_X_H_M 0x03 
+#define LSM303_REGISTER_MAG_OUT_X_L_M 0x04 
+#define LSM303_REGISTER_MAG_OUT_Z_H_M 0x05 
+#define LSM303_REGISTER_MAG_OUT_Z_L_M 0x06 
+#define LSM303_REGISTER_MAG_OUT_Y_H_M 0x07 
+#define LSM303_REGISTER_MAG_OUT_Y_L_M 0x08
+
+#define LSM303_REGISTER_MAG_CRA_REG_M    0x00
+#define LSM303_REGISTER_MAG_CRB_REG_M    0x01
+#define LSM303_REGISTER_MAG_MR_REG_M     0x02
+#define LSM303_REGISTER_MAG_OUT_X_H_M    0x03
+#define LSM303_REGISTER_MAG_OUT_X_L_M    0x04
+#define LSM303_REGISTER_MAG_OUT_Z_H_M    0x05
+#define LSM303_REGISTER_MAG_OUT_Z_L_M    0x06
+#define LSM303_REGISTER_MAG_OUT_Y_H_M    0x07
+#define LSM303_REGISTER_MAG_OUT_Y_L_M    0x08
+#define LSM303_REGISTER_MAG_SR_REG_Mg    0x09
+#define LSM303_REGISTER_MAG_IRA_REG_M    0x0A
+#define LSM303_REGISTER_MAG_IRB_REG_M    0x0B
+#define LSM303_REGISTER_MAG_IRC_REG_M    0x0C
+#define LSM303_REGISTER_MAG_TEMP_OUT_H_M 0x31
+#define LSM303_REGISTER_MAG_TEMP_OUT_L_M 0x32
+
+                                            // MD1 MD0
+#define LSM303_REGISTER_MAG_MR_REG_CCM 0x00 //   0   0 = continuous-conversion mode
+#define LSM303_REGISTER_MAG_MR_REG_SCM 0x01 //   0   1 = single-conversion mode
+#define LSM303_REGISTER_MAG_MR_REG_SM  0x02 //   0   1 = sleep-mode. device is placed in sleep-mode
+
+#define LSM303_REGISTER_MAG_CRA_REG_M_0_75HZ (0 << 2) // 0.75 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_1_5HZ  (1 << 2) // 1.5 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_3_0HZ  (2 << 2) // 3.0 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_7_5HZ  (3 << 2) // 7.5 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_15HZ   (4 << 2) // 15 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_30HZ   (5 << 2) // 30 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_75HZ   (6 << 2) // 75 Hz
+#define LSM303_REGISTER_MAG_CRA_REG_M_220HZ  (7 << 2) // 220 Hz
+
+#define LSM303_MULTIPLE_REGISTER_READS (1 << 7) // MSB set to 1 in the command is telling the LSM303 to increment the register pointer after each read/write (https://www.pololu.com/product/1268)
+
+Serial serial(SERIAL_TX, SERIAL_RX);
+I2C i2c(I2C_SDA, I2C_SCL); // PB_9, PB_8
+Timer elapsed_time;
+
+int16_t x;
+int16_t y;
+int16_t z;
+bool magn_found = false;
+
+uint8_t i2c_read8_reg(uint8_t address, int8_t reg) {
+    char i2cBuffer[1];
+    i2cBuffer[0] = reg;
+    i2c.write(address, i2cBuffer, 1);
+
+    i2c.read(address, i2cBuffer, 1);
+
+    return (uint8_t)i2cBuffer[0];
+}
+
+void i2c_write8_reg(uint8_t address, int8_t reg, int8_t value) {
+    char i2cBuffer[2];
+    i2cBuffer[0] = reg;
+    i2cBuffer[1] = value;
+    i2c.write(address, i2cBuffer, 2);
+}
+
+void read_magn() {
+    char i2cBuffer[1];
+
+    i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_X_H_M;
+    i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    x = (i2cBuffer[0] << 8);
+
+    i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_X_L_M;
+    i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    x |= i2cBuffer[0];
+
+    i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Y_H_M;
+    i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    y = (i2cBuffer[0] << 8);
+
+    i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Y_L_M;
+    i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    y |= i2cBuffer[0];
+
+    i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Z_H_M;
+    i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    z = (i2cBuffer[0] << 8);
+
+    i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Z_L_M;
+    i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
+    z |= i2cBuffer[0];
+}
+
+int main() {
+    serial.baud(115200);
+    i2c.frequency((uint32_t)100e3);
+
+    serial.printf("LSM303DLHC magnetometer example...\n");
+
+    // set the magnetometer data output rate (Hz)
+    i2c_write8_reg(MAGN_I2C_ADDRESS, LSM303_REGISTER_MAG_CRA_REG_M, LSM303_REGISTER_MAG_CRA_REG_M_3_0HZ);
+
+    // read the magnetometer register for the value we set above
+    uint8_t default_val = i2c_read8_reg(MAGN_I2C_ADDRESS, LSM303_REGISTER_MAG_CRA_REG_M);
+
+    if (default_val == LSM303_REGISTER_MAG_CRA_REG_M_3_0HZ) {
+        magn_found = true;
+        serial.printf("magn found\n");
+    } else {
+        serial.printf("magn NOT found\n");
+    }
+
+    if (magn_found) {
+        // enable the magnetometer
+        i2c_write8_reg(MAGN_I2C_ADDRESS, LSM303_REGISTER_MAG_MR_REG_M, LSM303_REGISTER_MAG_MR_REG_CCM);
+
+        elapsed_time.start();
+
+        while (true) {
+            if (elapsed_time.read_ms() > 200) { // print every x ms
+                read_magn();
+                elapsed_time.reset();
+                serial.printf("x: %d; y: %d; z: %d\n", x, y, z);
+                serial.printf("**************************\n");
+            }
+        }
+    }
+}
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