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tweaked cal_postgain_binary() so it gets the least significant bit right

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This commit is contained in:
Frank Mori Hess 2003-04-28 00:14:44 +00:00
parent 1912648a7e
commit 3337aa150f
1 changed files with 31 additions and 35 deletions
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66
comedi_calibrate/comedi_calibrate.c
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@ -211,7 +211,7 @@ ok:
"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.");
"quickly in the future.\n");
if(verbose<1)verbose=1;
if(device_status==STATUS_UNKNOWN){
do_reset=1;
@ -525,70 +525,61 @@ void cal_binary( calibration_setup_t *setup, int obs, int dac)
void cal_postgain_binary( calibration_setup_t *setup, int obs1, int obs2, int dac)
{
int x1, x2, x;
double y1, y2, y;
int x0, x1, x2, x, polarity;
double y0, y1, y2;
new_sv_t sv1, sv2;
double target = setup->observables[obs1].target - setup->observables[obs2].target;
unsigned int chanspec1 = setup->observables[obs1].observe_insn.chanspec;
unsigned int chanspec2 = setup->observables[obs2].observe_insn.chanspec;
unsigned int bit;
DPRINT(0,"postgain binary: %s, %s\n", setup->observables[obs1].name,
setup->observables[obs2].name);
x1 = 0;
x2 = setup->caldacs[dac].maxdata;
update_caldac( setup, dac, x1 );
x0 = x1 = x2 = 0;
update_caldac( setup, dac, x0 );
usleep(100000);
preobserve( setup, obs1);
new_sv_init(&sv1, setup->dev, setup->ad_subdev,chanspec1);
sv1.settling_time_ns = setup->settling_time_ns;
new_sv_measure( setup->dev, &sv1);
y1 = sv1.average;
y0 = sv1.average;
preobserve( setup, obs2);
new_sv_init(&sv2, setup->dev, setup->ad_subdev,chanspec2);
sv2.settling_time_ns = setup->settling_time_ns;
new_sv_measure( setup->dev, &sv2);
y1 -= sv2.average;
y0 -= sv2.average;
y1 = y2 = y0;
update_caldac( setup, dac, x2 );
usleep(100000);
preobserve( setup, obs1);
new_sv_init(&sv1, setup->dev, setup->ad_subdev,chanspec1);
sv1.settling_time_ns = setup->settling_time_ns;
new_sv_measure( setup->dev, &sv1);
y2 = sv1.average;
preobserve( setup, obs2);
new_sv_init(&sv2, setup->dev, setup->ad_subdev,chanspec2);
sv2.settling_time_ns = setup->settling_time_ns;
new_sv_measure( setup->dev, &sv2);
y2 -= sv2.average;
bit = 1;
while( ( bit << 1 ) < setup->caldacs[dac].maxdata )
bit <<= 1;
for( ; bit; bit >>= 1 )
{
x2 = x1 | bit;
x = 0;
while(x2-x1 > 1){
x = (x1 + x2 + 1)/2;
DPRINT(3,"trying %d\n",x);
update_caldac( setup, dac, x );
update_caldac( setup, dac, x2 );
usleep(100000);
preobserve( setup, obs1);
new_sv_init(&sv1, setup->dev, setup->ad_subdev,chanspec1);
sv1.settling_time_ns = setup->settling_time_ns;
new_sv_measure( setup->dev, &sv1);
y = sv1.average;
y2 = sv1.average;
preobserve( setup, obs2);
new_sv_init(&sv2, setup->dev, setup->ad_subdev,chanspec2);
sv2.settling_time_ns = setup->settling_time_ns;
new_sv_measure( setup->dev, &sv2);
y -= sv2.average;
y2 -= sv2.average;
if(fabs(y2 - target) > fabs(y1 - target)){
x2 = x;
y2 = y;
}else{
x1 = x;
y1 = y;
DPRINT(3,"trying %d, result %g, target %g\n",x2,y2,target);
if( (y2 - y0) > 0.0 ) polarity = 1;
else polarity = -1;
if( (y2 - target) * polarity < 0.0 ){
x1 = x2;
y1 = y2;
}
if(verbose>=3){
@ -599,6 +590,11 @@ void cal_postgain_binary( calibration_setup_t *setup, int obs1, int obs2, int da
}
}
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){
preobserve( setup, obs1);