Hi! I am trying to run the AVR Studio project https://www.pololu.com/file/download/LSM303DLH-orangutan-example-code.zip?file_id=0J436 listed at the bottom of the LM303DLH product page as an intro to how this piece works.
I connected SDA → PC1
SCL → PC0
Vin → Vcc located next to PC0
Gnd → Gnd located next to PC0 and Vcc
In the code I only changed the PC4 and PC5 to PC0 and PC1.
/*
* compass: for the Orangutan LV, SV, SVP, and X2.
*
* This example program demonstrates how to use the LSM303DLH 3D compass and
* accelerometer carrier with an Orangutan robot controller.
*
* The LSM303DLH carrier should be connected to the Orangutan's I2C pins; on the
* LV and SV, these are PC5 and PC4 for SCL and SDA, respectively, and on the
* SVP and X2, these are PC0 and PC1, respectively. (PC0 and PC1 are LCD data
* lines on the X2, but this code will work on it if the LCD is not used, or
* used in 4-bit mode.)
*
* https://www.pololu.com
* https://forum.pololu.com
*/
#include <avr/io.h>
#include <pololu/orangutan.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "vector.h"
/*
* This program assumes that the LSM303DLH carrier is oriented with X pointing
* to the right, Y pointing backward, and Z pointing down (toward the ground).
* The code compensates for tilts of up to 90 degrees away from horizontal.
* Vector p should be defined as pointing forward, parallel to the ground,
* with coordinates {X, Y, Z}.
*/
vector p = {0, -1, 0};
/*
* m_max and m_min are calibration values for the maximum and minimum
* measurements recorded on each magnetic axis, which can vary for each
* LSM303DLH. You should replace the values below with max and min readings from
* your particular device.
*
* To obtain the max and min values, you can use this program's
* calibration mode, which is enabled by pressing one of the pushbuttons. While
* calibration mode is active, point each of the axes of the LSM303DLH toward
* and away from the earth's North Magnetic Pole. Due to space constraints on an
* 8x2 LCD, only one axis is displayed at a time; each button selects an axis to
* display (top = X, middle = Y, bottom = Z), and pressing any button a second
* time exits calibration mode and returns to normal operation.
*/
vector m_max = {340, 517, 416};
vector m_min = {-642, -496, -462};
char* ribbon = " N NE E SE S SW W NW N ";
enum calibration_mode {CAL_NONE, CAL_X, CAL_Y, CAL_Z};
void i2c_start() {
TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN); // send start condition
while (!(TWCR & (1 << TWINT)));
}
void i2c_write_byte(char byte) {
TWDR = byte;
TWCR = (1 << TWINT) | (1 << TWEN); // start address transmission
while (!(TWCR & (1 << TWINT)));
}
char i2c_read_byte() {
TWCR = (1 << TWINT) | (1 << TWEA) | (1 << TWEN); // start data reception, transmit ACK
while (!(TWCR & (1 << TWINT)));
return TWDR;
}
char i2c_read_last_byte() {
TWCR = (1 << TWINT) | (1 << TWEN); // start data reception
while (!(TWCR & (1 << TWINT)));
return TWDR;
}
void i2c_stop() {
TWCR = (1 << TWINT) | (1 << TWSTO) | (1 << TWEN); // send stop condition
}
// Returns a set of acceleration and raw magnetic readings from the cmp01a.
void read_data_raw(vector *a, vector *m)
{
// read accelerometer values
i2c_start();
i2c_write_byte(0x30); // write acc
i2c_write_byte(0xa8); // OUT_X_L_A, MSB set to enable auto-increment
i2c_start(); // repeated start
i2c_write_byte(0x31); // read acc
unsigned char axl = i2c_read_byte();
unsigned char axh = i2c_read_byte();
unsigned char ayl = i2c_read_byte();
unsigned char ayh = i2c_read_byte();
unsigned char azl = i2c_read_byte();
unsigned char azh = i2c_read_last_byte();
i2c_stop();
// read magnetometer values
i2c_start();
i2c_write_byte(0x3C); // write mag
i2c_write_byte(0x03); // OUTXH_M
i2c_start(); // repeated start
i2c_write_byte(0x3D); // read mag
unsigned char mxh = i2c_read_byte();
unsigned char mxl = i2c_read_byte();
unsigned char myh = i2c_read_byte();
unsigned char myl = i2c_read_byte();
unsigned char mzh = i2c_read_byte();
unsigned char mzl = i2c_read_last_byte();
i2c_stop();
a->x = axh << 8 | axl;
a->y = ayh << 8 | ayl;
a->z = azh << 8 | azl;
m->x = mxh << 8 | mxl;
m->y = myh << 8 | myl;
m->z = mzh << 8 | mzl;
}
// Returns a set of acceleration and adjusted magnetic readings from the cmp01a.
void read_data(vector *a, vector *m)
{
read_data_raw(a, m);
// shift and scale
m->x = (m->x - m_min.x) / (m_max.x - m_min.x) * 2 - 1.0;
m->y = (m->y - m_min.y) / (m_max.y - m_min.y) * 2 - 1.0;
m->z = (m->z - m_min.z) / (m_max.z - m_min.z) * 2 - 1.0;
}
// Returns a heading (in degrees) given an acceleration vector a due to gravity, a magnetic vector m, and a facing vector p.
int get_heading(const vector *a, const vector *m, const vector *p)
{
vector E;
vector N;
// cross magnetic vector (magnetic north + inclination) with "down" (acceleration vector) to produce "east"
vector_cross(m, a, &E);
vector_normalize(&E);
// cross "down" with "east" to produce "north" (parallel to the ground)
vector_cross(a, &E, &N);
vector_normalize(&N);
// compute heading
int heading = round(atan2(vector_dot(&E, p), vector_dot(&N, p)) * 180 / M_PI);
if (heading < 0)
heading += 360;
return heading;
}
int main()
{
DDRC = 0; // all inputs
PORTC = (1 << PORTC1) | (1 << PORTC0); // enable pull-ups on SDA and SCL, respectively
TWSR = 0; // clear bit-rate prescale bits
TWBR = 17; // produces an SCL frequency of 400 kHz with a 20 MHz CPU clock speed
clear();
//enable accelerometer
i2c_start();
i2c_write_byte(0x30); // write acc
i2c_write_byte(0x20); // CTRL_REG1_A
i2c_write_byte(0x27); // normal power mode, 50 Hz data rate, all axes enabled
i2c_stop();
//enable magnetometer
i2c_start();
i2c_write_byte(0x3C); // write mag
i2c_write_byte(0x02); // MR_REG_M
i2c_write_byte(0x00); // continuous conversion mode
i2c_stop();
vector a, m;
char ribbon_segment[8];
unsigned char button;
enum calibration_mode mode = CAL_NONE;
vector cal_m_max = {0, 0, 0};
vector cal_m_min = {0, 0, 0};
while(1)
{
// see if a button was pressed to enable calibration mode
// each button displays max and min measurements for one axis:
// top = X, middle = Y, bottom = Z
// if any button is pressed a second time, return to normal mode
button = get_single_debounced_button_press(ANY_BUTTON);
if (button & TOP_BUTTON)
{
if (mode != CAL_X)
mode = CAL_X;
else
mode = CAL_NONE;
}
else if (button & MIDDLE_BUTTON)
{
if (mode != CAL_Y)
mode = CAL_Y;
else
mode = CAL_NONE;
}
else if (button & BOTTOM_BUTTON)
{
if (mode != CAL_Z)
mode = CAL_Z;
else
mode = CAL_NONE;
}
if (mode == CAL_NONE) // normal mode - display heading and compass ribbon
{
vector a_avg = {0,0,0}, m_avg = {0,0,0};
// take 5 acceleration and magnetic readings and average them
for(int i = 0; i < 5; i++)
{
read_data(&a, &m);
a_avg.x += a.x;
a_avg.y += a.y;
a_avg.z += a.z;
m_avg.x += m.x;
m_avg.y += m.y;
m_avg.z += m.z;
}
a_avg.x /= 5;
a_avg.y /= 5;
a_avg.z /= 5;
m_avg.x /= 5;
m_avg.y /= 5;
m_avg.z /= 5;
int heading = get_heading(&a_avg, &m_avg, &p);
// select the portion of the ribbon to display
strlcpy(ribbon_segment, &ribbon[(heading + 5) / 10], 8);
clear();
print_long(heading);
lcd_goto_xy(4, 0);
print_character('v'); // center indicator
lcd_goto_xy(1, 1);
print(ribbon_segment); // ribbon segment
}
else // calibration mode - record and display max/min measurements
{
read_data_raw(&a, &m);
if (m.x < cal_m_min.x) cal_m_min.x = m.x;
if (m.x > cal_m_max.x) cal_m_max.x = m.x;
if (m.y < cal_m_min.y) cal_m_min.y = m.y;
if (m.y > cal_m_max.y) cal_m_max.y = m.y;
if (m.z < cal_m_min.z) cal_m_min.z = m.z;
if (m.z > cal_m_max.z) cal_m_max.z = m.z;
clear();
switch (mode)
{
case CAL_X:
print("Xmax:");
print_long(cal_m_max.x);
lcd_goto_xy(0, 1);
print("min:");
print_long(cal_m_min.x);
break;
case CAL_Y:
print("Ymax:");
print_long(cal_m_max.y);
lcd_goto_xy(0, 1);
print("min:");
print_long(cal_m_min.y);
break;
default:
print("Zmax:");
print_long(cal_m_max.z);
lcd_goto_xy(0, 1);
print("min:");
print_long(cal_m_min.z);
break;
}
}
delay_ms(100);
}
}
After that, it builds and programs fine, but the LCD remains blank and there is a faint clicking sound. Are there other things specific to the SVP-324 that I need to change in this code for it to work? Are my connections to the hardware correct? Thanks for your help!
