this is totally broken

git-svn-id: https://bucket.mit.edu/svn/nilm/zoom@7687 ddd99763-3ecb-0310-9145-efcb8ce7c51f

firmware/scaling.c

@@ -1,48 +1,77 @@
 #include "config.h"
-#include "scaling.h"
+#include "calibrate.h"
 #include "util.h"
+#include "adc.h"
+#include "dac.h"
 
-uint16_t current_to_dac(float amps)
-{
-	float tmp;
-	uint16_t dacc;
-
-	tmp = 536.0 / 1.0 * amps + 32524;
-	if (tmp < 0)
-		tmp = 0;
-	if (tmp > 65535)
-		tmp = 65535;
-	dacc = (uint16_t)(tmp + 0.5);
+static float scale;  /* delta(DAC) / delta(ADC) */
 
-	return dacc;
+/* Initialize.  Assume some relatively-safe scaling if no calibration is run */
+void calibrate_init(void)
+{
+	scale = 0;
 }
 
-/* Convert the DAC output value to an effective current in the measuring loop */
-float dac_to_current(uint16_t dacv)
+/* Seek with the DAC to reach a specific ADC value, adjusting
+ * calibration if necessary */
+uint16_t seek(int16_t desired)
 {
-	float amps;
-	amps = ((float)dacv - 32524.0) * 1.0 / 536.0;
- 	return amps;
+	int32_t dac = 32768;
+	int16_t actual;
+	int32_t delta = 0;
+
+	while (1)
+	{
+		/* get current location */
+		dac_write(dac);
+		msleep(1);
+		actual = adc_get();
+
+		/* adjust scaling to match the jump we just saw */
+		if (delta) {
+			
+		}
+
+		if (actual == desired)
+			return dac;
+
+		/* figure out how much to change the DAC */
+		delta = (desired - actual) * scale;
+
+		
+		dac -= (desired - actual) * scale;
+
+		
+	}
+	uint16_t dac = 0;
+	dac_write(0x8000
+
 }
 
-float adc12_to_current(int16_t picv)
+/* Perform calibration */
+void do_calibrate(void)
 {
-	float amps;
-
-	if (picv < 0)
-		picv = 0;
-	if (picv > 2047)
-		picv = 2047;
-	
-	amps = (picv - 1024.0) / 404.0;
-	return amps;
-}
+	uint16_t daczero, x;
+	float x1, y1, x2, y2;
+
+	/* Zero ADC */
+	daczero = seek(1024);
 
-float dac_current_min;
-float dac_current_max;
+	/* Go halfway down and take an accurate sample */
+	x = seek(512);
+	oversample(x, &x1, &y1);
+
+	/* Go halfway up and take an accurate sample */
+	x = seek(768);
+	oversample(x, &x2, &y2);
+
+	/* Scale factor is 1/slope */
+	scale = (x2 - x1) / (y2 - y1);
+}
 
-void scaling_init(void)
+/* convert from (counts at ADC) to (counts at DAC) */
+int32_t adc_toc(int16_t adc)
 {
-	dac_current_min = dac_to_current(0x0000);
-	dac_current_max = dac_to_current(0xffff);
+	int32_t r = ((float) adc) * scale;
+	return r;
 }

firmware/scaling.h

@@ -1,13 +1,12 @@
-#ifndef SCALING_H
-#define SCALING_H
+#ifndef CALIBRATE_H
+#define CALIBRATE_H
 
-float adc12_to_current(int16_t picv);
-float dac_to_current(uint16_t dacv);
-uint16_t current_to_dac(float amps);
+void calibrate_init(void);
 
-void scaling_init(void);
+/* Do calibration routine */
+void do_calibrate(void);
 
-extern float dac_current_min;
-extern float dac_current_max;
+/* convert from (counts at ADC) to (counts at DAC) */
+int32_t adc_to_dac(int16_t adc);
 
 #endif