# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1381769439 0
# Node ID dc85b7ea00568c7e37600304ad811d17cf7c1164
# Parent  c169fa933f1265d04c4224a35892d891f99e3892
Added support for reading magnetometer calibration data from a file.
Added a special signal handler for the calibration program to produce usable
data for such a settings file when the program is interrupted.

diff -r c169fa933f12 -r dc85b7ea0056 calibrate.c
--- a/calibrate.c	Mon Oct 14 16:22:35 2013 +0000
+++ b/calibrate.c	Mon Oct 14 16:50:39 2013 +0000
@@ -18,14 +18,22 @@
 #include "shutdown.h"
 #include "geo.h"
 
+vectorf vmin = {{0, 0, 0}},
+        vmax = {{0, 0, 0}};
+
+void calibrate_shutdown(int signum)
+{
+    printf("\n%-6.1f %-6.1f %-6.1f %-6.1f %-6.1f %-6.1f\n",
+        vmin.x, vmin.y, vmin.z, vmax.x, vmax.y, vmax.z);
+    init_shutdown(signum);
+}
+
 /* Main program. */
 
 int main(int argc, char *argv[])
 {
     uint8_t result[6];
     vectorf value,
-            vmin = {{1, 1, 1}},
-            vmax = {{-1, -1, -1}},
             valueB[IMU_ACCEL_BUFFER_SIZE];
     int argno = 1, vindex = 0;
     bool gyroscope = false, accelerometer = false, magnetometer = false,
@@ -64,7 +72,7 @@
         normalised = true;
     }
 
-    signal(SIGINT, init_shutdown);
+    signal(SIGINT, calibrate_shutdown);
 
     /* Access the 8:10 port. */
 
diff -r c169fa933f12 -r dc85b7ea0056 imu.h
--- a/imu.h	Mon Oct 14 16:22:35 2013 +0000
+++ b/imu.h	Mon Oct 14 16:50:39 2013 +0000
@@ -201,6 +201,7 @@
 #define IMU_UGAUSS_FACTOR           IMU_4_0G_UNIT
 #define IMU_MAGNET_SCALE            IMU_MAGNET_CRB_REG_4_0G
 #define IMU_MAGNET_FREQ             IMU_MAGNET_CRA_REG_30HZ
+#define IMU_MAGNET_SETTINGS_FILE    "imu-magnet.cfg"
 
 #define ACCEL_G                     9.81 /* ms**-2 */
 
diff -r c169fa933f12 -r dc85b7ea0056 measure.c
--- a/measure.c	Mon Oct 14 16:22:35 2013 +0000
+++ b/measure.c	Mon Oct 14 16:50:39 2013 +0000
@@ -12,6 +12,8 @@
  * (at your option) any later version.
  */
 
+#include <stdio.h>
+#include <stdlib.h>
 #include <sys/time.h>
 #include <unistd.h>
 #include <pthread.h>
@@ -30,6 +32,10 @@
 void ui_calibrate(bool using_filter, int (*print)(const char *, ...), void (*flush)())
 {
     vectorf tmpB[1];
+    FILE *magnetcfg;
+    char fieldmins[3][8], fieldmaxs[3][8], *endptr;
+    double value;
+    int i;
 
     print("Calibrating...\n");
     flush();
@@ -53,6 +59,33 @@
 
     print("Calibrated using (%.4f, %.4f, %.4f).\n", acceleration0.x, acceleration0.y, acceleration0.z);
     flush();
+
+    /* Read magnetometer settings, if possible. */
+
+    magnetcfg = fopen(IMU_MAGNET_SETTINGS_FILE, "r");
+
+    if (magnetcfg != NULL)
+    {
+        fscanf(magnetcfg, "%7s %7s %7s %7s %7s %7s",
+            fieldmins[0], fieldmins[1], fieldmins[2],
+            fieldmaxs[0], fieldmaxs[1], fieldmaxs[2]);
+
+        for (i = 0; i < 3; i++)
+        {
+            value = strtod(fieldmins[i], &endptr);
+            if (endptr != fieldmins[i])
+                fieldmin.axis[i] = value;
+            value = strtod(fieldmaxs[i], &endptr);
+            if (endptr != fieldmaxs[i])
+                fieldmax.axis[i] = value;
+        }
+
+        print("Calibrated using (%.1f, %.1f, %.1f), (%.1f, %.1f, %.1f).\n",
+            fieldmin.x, fieldmin.y, fieldmin.z,
+            fieldmax.x, fieldmax.y, fieldmax.z);
+
+        fclose(magnetcfg);
+    }
 }
 
 void *get_measurements(void *arg)