From 53a43ff0a711174a40ec6d05e513e285adbcf9b8 Mon Sep 17 00:00:00 2001
From: Frank Mori Hess <fmhess@speakeasy.net>
Date: Fri, 6 Jun 2003 14:59:29 +0000
Subject: [PATCH] make sure we aren't out-of-range when doing unipolar postgain
 offset

---
 comedi_calibrate/cal_common.c       | 15 ++++++++++
 comedi_calibrate/calib.h            |  1 +
 comedi_calibrate/comedi_calibrate.c | 46 +++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+)

diff --git a/comedi_calibrate/cal_common.c b/comedi_calibrate/cal_common.c
index 4d3ed60..ad37ea0 100644
--- a/comedi_calibrate/cal_common.c
+++ b/comedi_calibrate/cal_common.c
@@ -51,6 +51,13 @@ void generic_do_linearity( calibration_setup_t *setup,
 	sc_push_caldac( saved_cal, setup->caldacs[ caldac ] );
 }
 
+void generic_peg( calibration_setup_t *setup,
+	comedi_calibration_setting_t *saved_cal, int observable, int caldac, int maximize )
+{
+	if( caldac < 0 || observable < 0 ) return;
+	peg_binary( setup, observable, caldac, maximize );
+}
+
 void generic_prep_adc_caldacs( calibration_setup_t *setup,
 	const generic_layout_t *layout, unsigned int channel, unsigned int range )
 {
@@ -172,6 +179,14 @@ static void generic_do_adc_postgain_offset( calibration_setup_t *setup, const ge
 	{
 		lowgain = get_unipolar_lowgain( setup->dev, setup->ad_subdev );
 		highgain = get_unipolar_highgain( setup->dev, setup->ad_subdev );
+
+		reset_caldac( setup, layout->adc_postgain_offset( channel ) );
+		/* need to make sure we aren't stuck on zero for unipolar,
+		 * by setting pregain offset to maximum */
+		generic_peg( setup, current_cal, layout->adc_ground_observable( setup, channel, lowgain ),
+			layout->adc_offset( channel ), 1 );
+		generic_peg( setup, current_cal, layout->adc_ground_observable( setup, channel, lowgain ),
+			layout->adc_offset_fine( channel ), 1 );
 	}else
 	{
 		lowgain = get_bipolar_lowgain( setup->dev, setup->ad_subdev );
diff --git a/comedi_calibrate/calib.h b/comedi_calibrate/calib.h
index f7bb35a..e62294f 100644
--- a/comedi_calibrate/calib.h
+++ b/comedi_calibrate/calib.h
@@ -121,6 +121,7 @@ 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);
 void cal_relative_binary( calibration_setup_t *setup, int obs1, int obs2, int dac);
 void cal_linearity_binary( calibration_setup_t *setup, int obs1, int obs2, int obs3, int dac);
+void peg_binary( calibration_setup_t *setup, int obs, int dac, int maximize );
 
 /* misc and temp */
 
diff --git a/comedi_calibrate/comedi_calibrate.c b/comedi_calibrate/comedi_calibrate.c
index a8716d8..a146bbe 100644
--- a/comedi_calibrate/comedi_calibrate.c
+++ b/comedi_calibrate/comedi_calibrate.c
@@ -531,6 +531,52 @@ void cal1_fine( calibration_setup_t *setup, int obs, int dac )
 	}
 }
 
+void peg_binary( calibration_setup_t *setup, int obs, int dac, int maximize )
+{
+	int x0, x1, x;
+	double y0, y1;
+	new_sv_t sv;
+	unsigned int chanspec = setup->observables[obs].observe_insn.chanspec;
+	int polarity;
+
+	DPRINT(0,"binary peg: %s\n", setup->observables[obs].name);
+	preobserve( setup, obs);
+
+	comedi_set_global_oor_behavior( COMEDI_OOR_NUMBER );
+
+	my_sv_init(&sv, setup, setup->ad_subdev, chanspec);
+
+	x0 = setup->caldacs[dac].maxdata;
+	update_caldac( setup, dac, x0 );
+	usleep(caldac_settle_usec);
+	new_sv_measure( setup->dev, &sv);
+	y0 = sv.average;
+
+	x1 = 0;
+	update_caldac( setup, dac, x1 );
+	usleep(caldac_settle_usec);
+	new_sv_measure( setup->dev, &sv);
+	y1 = sv.average;
+
+	if( (y0 - y1) > 0.0 ) polarity = 1;
+	else polarity = -1;
+
+	if( maximize )
+	{
+		if( polarity > 0 ) x = x0;
+		else x = x1;
+	}else
+	{
+		if( polarity > 0 ) x = x1;
+		else x = x0;
+	}
+	update_caldac( setup, dac, x );
+	DPRINT(0,"caldac[%d] set to %d\n",dac,x);
+	if(verbose>=3){
+		measure_observable( setup, obs);
+	}
+}
+
 void cal_binary( calibration_setup_t *setup, int obs, int dac)
 {
 	int x0, x1, x2, x;
-- 
2.26.2