okay, _really_ got last bit correct with cal_binary() this time.

diff --git a/comedi_calibrate/comedi_calibrate.c b/comedi_calibrate/comedi_calibrate.c
index 3fcb928269db13f94a23b6d128188aedbd5c83ba..2a0dafa8406a1162850744162e5670c1a47f90ab 100644 (file)
--- a/comedi_calibrate/comedi_calibrate.c
+++ b/comedi_calibrate/comedi_calibrate.c
@@ -207,8 +207,11 @@ ok:
        device_status = setup.status;
 
        if(device_status<STATUS_DONE){
-               printf("Warning: device not fully calibrated due to insufficient information\n");
-               printf("Please send this output to <ds@schleef.org>\n");
+               printf("Warning: device may not be not fully calibrated due to "
+                       "insufficient information.\n"
+                       "Please send this output to <ds@schleef.org>.\n"
+                       "This output will also allow comedi_calibrate to execute more\n"
+                       "quickly in the future.");
                if(verbose<1)verbose=1;
                if(device_status==STATUS_UNKNOWN){
                        do_reset=1;
@@ -463,9 +466,9 @@ void cal1_fine( calibration_setup_t *setup, int obs, int dac )
 
 void cal_binary( calibration_setup_t *setup, int obs, int dac)
 {
-       int x0, x;
+       int x0, x1, x2, x;
        unsigned int bit;
-       double y0, y;
+       double y0, y1, y2;
        new_sv_t sv;
        double target = setup->observables[obs].target;
        unsigned int chanspec = setup->observables[obs].observe_insn.chanspec;
@@ -474,49 +477,46 @@ void cal_binary( calibration_setup_t *setup, int obs, int dac)
        DPRINT(0,"binary: %s\n", setup->observables[obs].name);
        preobserve( setup, obs);
 
-       bit = 1;
-       while( ( bit << 1 ) < setup->caldacs[dac].maxdata )
-               bit <<= 1;
-
        new_sv_init(&sv, setup->dev, setup->ad_subdev, chanspec);
        sv.settling_time_ns = setup->settling_time_ns;
 
-       x0 = 0;
+       x0 = x1 = x2 = 0;
        update_caldac( setup, dac, x0 );
        usleep(100000);
        new_sv_measure( setup->dev, &sv);
-       y0 = sv.average;
-
-       x = bit;
-       update_caldac( setup, dac, x );
-       usleep(100000);
-       new_sv_measure( setup->dev, &sv);
-       y = sv.average;
-
-       if( y > y0 ) polarity = 1;
-       else polarity = -1;
-
-       if( (y - target) * polarity > 0.0 )
-               x &= ~bit;
+       y0 = y1 = y2 = sv.average;
 
-       for( bit = bit >> 1; bit; bit >>= 1 ){
-               x |= bit;
-               DPRINT(3,"trying %d\n",x);
+       bit = 1;
+       while( ( bit << 1 ) < setup->caldacs[dac].maxdata )
+               bit <<= 1;
+       for( ; bit; bit >>= 1 ){
+               x2 = x1 | bit;
 
-               update_caldac( setup, dac, x );
+               update_caldac( setup, dac, x2 );
                usleep(100000);
-
                new_sv_measure( setup->dev, &sv);
-               y = sv.average;
+               y2 = sv.average;
+               DPRINT(3,"trying %d, result %g, target %g\n",x2,y2,target);
+
+               if( (y2 - y0) > 0.0 ) polarity = 1;
+               else polarity = -1;
 
-               if( (y - target) * polarity > 0.0 )
-                       x &= ~bit;
+               if( (y2 - target) * polarity < 0.0 ){
+                       x1 = x2;
+                       y1 = y2;
+               }
 
                if(verbose>=3){
                        measure_observable( setup, obs);
                }
        }
 
+       // get that least signficant bit right
+       if( fabs( y1 - target ) < fabs( y2 - target ) )
+               x = x1;
+       else x = x2;
+
+       update_caldac( setup, dac, x );
        DPRINT(0,"caldac[%d] set to %d\n",dac,x);
        if(verbose>=3){
                measure_observable( setup, obs);