Added new float state; Some fixes

Typical charge cycle: MPPT until 14.4V, then switch to CV and hold
14.4V. After 2 hours switch to float charging at 13.8V.

src/main.c

@@ -17,7 +17,7 @@
 #include "lcd.h"
 #include "debug.h"
 
-#define CONV_PWM_PERIOD 960
+#define CONV_PWM_PERIOD 360
 #define CONV_PWM_MAX (98*CONV_PWM_PERIOD/100)
 
 #define TIM_CH_CONV      TIM_OC1
@@ -31,6 +31,7 @@
 enum OperState {
 	Bootstrap,
 	ConvConstVoltage,
+	ConvFloat,
 	ConvConstCurrent,
 	ConvMPP,
 	Idle,
@@ -358,6 +359,21 @@ struct PowerState {
 	fxp_t power_avg;
 };
 
+static void load_on(void)
+{
+	gpio_set(GPIOA, GPIO15);
+}
+
+static void load_off(void)
+{
+	gpio_clear(GPIOA, GPIO15);
+}
+
+static bool load_status(void)
+{
+	return gpio_get(GPIOA, GPIO15) != 0;
+}
+
 static void report_status(struct PowerState *power_state,
 		int32_t pwm, enum OperState operState)
 {
@@ -387,6 +403,10 @@ static void report_status(struct PowerState *power_state,
 
 	fxp_format(power_state->temp_avg, number, 1);
 	debug_send_string(number);
+	debug_send_string(":");
+
+	fxp_format_int(load_status(), number);
+	debug_send_string(number);
 	debug_send_string("\r\n");
 }
 
@@ -415,7 +435,7 @@ struct MPPState {
 #define MPP_TEST_DURATION (MPP_TEST_IGNORE_DURATION + MPP_TEST_ACCU_DURATION)
 
 #define MPP_TEST_STEPS 6
-const int32_t mpp_pwm_offsets[MPP_TEST_STEPS] = {-3, 4, -16, 15};
+const int32_t mpp_pwm_offsets[MPP_TEST_STEPS] = {-1, 2, -6, 5};
 
 static void mpp_run(
 		uint32_t time_in_state, struct MPPState *mpp_state,
@@ -522,16 +542,6 @@ static void mpp_run(
 	}
 }
 
-static void load_on(void)
-{
-	gpio_set(GPIOA, GPIO15);
-}
-
-static void load_off(void)
-{
-	gpio_clear(GPIOA, GPIO15);
-}
-
 int main(void)
 {
 	//uint32_t cpuload = 0;
@@ -554,6 +564,8 @@ int main(void)
 	fxp_t pErr = 0, iErr = 0;
 	fxp_t controlAction = 0;
 
+	fxp_t setPoint = 0;
+
 	uint32_t sleep_time = 10;
 	uint64_t force_display_update_time = 1000;
 
@@ -569,11 +581,13 @@ int main(void)
 	fxp_t AVG_FACT = fxp_from_float(0.01f);
 	fxp_t AVG_FACT_INV = fxp_sub(fxp_from_int(1), AVG_FACT);
 
-	fxp_t MAX_VOLTAGE = fxp_from_float(14.400f);
+	fxp_t MPP_MAX_VOLTAGE = fxp_from_float(14.400f);
-	fxp_t CONST_VOLTAGE = fxp_from_float(13.800f);
+	fxp_t CONST_VOLTAGE = MPP_MAX_VOLTAGE;
+	fxp_t CONST_FLOAT_VOLTAGE = fxp_from_float(13.800f);
 	fxp_t MAX_CURRENT = fxp_from_float( 5.000f);
 
-	fxp_t MPP_VOLTAGE_THR = fxp_sub(CONST_VOLTAGE, fxp_from_float(0.500f));
+	fxp_t VOLTAGE_THR_CV_TO_MPP = fxp_sub(CONST_VOLTAGE, fxp_from_float(0.300f));
+	fxp_t VOLTAGE_THR_FLOAT_TO_MPP = fxp_sub(CONST_FLOAT_VOLTAGE, fxp_from_float(0.300f));
 	fxp_t MPP_CURRENT_THR = fxp_sub(MAX_CURRENT, fxp_from_float(0.500f));
 
 	// input voltage must exceed output voltage by this value to leave idle mode
@@ -584,21 +598,21 @@ int main(void)
 	//
 	// If the battery voltage is below LOAD_LOW_VOLTAGE_THRESHOLD, the battery
 	// voltage is monitored more closely during idle mode.
-	fxp_t LOAD_ON_THRESHOLD = fxp_from_float(13.000f);
+	fxp_t LOAD_ON_THRESHOLD = fxp_from_float(13.500f);
-	fxp_t LOAD_OFF_THRESHOLD = fxp_from_float(11.200f);
+	fxp_t LOAD_OFF_THRESHOLD = fxp_from_float(12.500f);
-	fxp_t LOAD_LOW_VOLTAGE_THRESHOLD = fxp_from_float(11.600f);
+	fxp_t LOAD_LOW_VOLTAGE_THRESHOLD = fxp_from_float(12.600f);
 
 	// Calculated values
 	//fxp_t VIN_SCALE = fxp_from_float(3.3f * (100 + 10.0f) / 10.0f / 4095.0f);
 	//fxp_t VOUT_SCALE = fxp_from_float(3.3f * (100 + 12.0f) / 12.0f / 4095.0f);
 
 	// Calibrated from measurements
-	fxp_t VIN_SCALE = fxp_from_float(36.41f / 4096.0f);
+	fxp_t VIN_SCALE = fxp_from_float(36.23f / 4096.0f);
-	fxp_t VOUT_SCALE = fxp_from_float(30.87f / 4096.0f);
+	fxp_t VOUT_SCALE = fxp_from_float(30.75f / 4096.0f);
 
 	// current = adc • 0.00166 + -0.0725 = adc • m + t
-	fxp_t ADC2CURRENT_M = fxp_from_float( 0.00166f);
+	fxp_t ADC2CURRENT_M = fxp_from_float( 0.00225f);
-	fxp_t ADC2CURRENT_T = fxp_from_float(-0.07250f);
+	fxp_t ADC2CURRENT_T = fxp_from_float(-0.2255f);
 
 	/* if power changes by more than this factor, MPP is tested again */
 	MPP_MAX_POWER_CHANGE_FACTOR = fxp_from_float(0.2f);
@@ -739,14 +753,18 @@ int main(void)
 					timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 24);
 
 					if(time_in_state >= 10) { // bootstrap duration in ms
-						//iErr = 0;
+						// bootstrap off
+						timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
+
+						// go to next state
 						operState = nextState;
 					}
 					break;
 
 				case ConvConstVoltage:
-					// bootstrap off
+					if(time_in_state == 0) {
-					timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
+						iErr = 0;
+					}
 
 					// calculate error values
 					pErr = fxp_sub(CONST_VOLTAGE, power_state.vout_avg);
@@ -771,6 +789,76 @@ int main(void)
 
 					timer_set_oc_value(TIM1, TIM_CH_CONV, pwm);
 
+#ifdef DEBUG
+					if((time_in_state % 100) == 0) {
+						debug_send_string("pErr: ");
+						fxp_format(pErr, msg, 3);
+						debug_send_string(msg);
+						debug_send_string(" iErr: ");
+						fxp_format(iErr, msg, 3);
+						debug_send_string(msg);
+						debug_send_string(" controlAction: ");
+						fxp_format(controlAction, msg, 3);
+						debug_send_string(msg);
+						sentSomething = 1;
+					}
+#endif
+
+					if(time_in_state > 3600*1000) {
+						operState = ConvFloat;
+					}
+
+					if(time_in_state > 5000 && fxp_to_int(controlAction) > CONV_PWM_MAX && power_state.current_avg < CURRENT_THRESHOLD) {
+						operState = Bootstrap;
+						nextState = ConvConstVoltage;
+					}
+
+					if(time_in_state > 1000 && power_state.vout_avg < VOLTAGE_THR_CV_TO_MPP) {
+						pwm = CONV_PWM_MAX * 8 / 10;
+						operState = ConvMPP;
+					}
+
+					if(power_state.current_avg > MAX_CURRENT) {
+						operState = ConvConstCurrent;
+					}
+
+					if(power_state.vin_avg < power_state.vout_avg) {
+						operState = Idle;
+					}
+					break;
+
+				case ConvFloat:
+					if(time_in_state < 120000) {
+						setPoint =
+							fxp_add(CONST_VOLTAGE,
+								fxp_mult(fxp_sub(CONST_FLOAT_VOLTAGE, CONST_VOLTAGE), fxp_div(time_in_state, 120000)));
+					} else {
+						setPoint = CONST_FLOAT_VOLTAGE;
+					}
+
+					// calculate error values
+					pErr = fxp_sub(setPoint, power_state.vout_avg);
+					iErr = fxp_add(iErr, pErr);
+
+					// limit integral error range
+					if     (iErr >  IERR_LIMIT) iErr =  IERR_LIMIT;
+					else if(iErr < -IERR_LIMIT) iErr = -IERR_LIMIT;
+
+					// calculate the controller output ("action")
+					controlAction = fxp_add(
+							fxp_mult(pErr, PGAIN_CV),
+							fxp_mult(iErr, IGAIN_CV));
+
+					pwm = fxp_to_int(controlAction);
+
+					if(pwm > CONV_PWM_MAX) {
+						pwm = CONV_PWM_MAX;
+					} else if(pwm < 0) {
+						pwm = 0;
+					}
+
+					timer_set_oc_value(TIM1, TIM_CH_CONV, pwm);
+
 #ifdef DEBUG
 					if((time_in_state % 100) == 0) {
 						debug_send_string("pErr: ");
@@ -791,7 +879,8 @@ int main(void)
 						nextState = ConvConstVoltage;
 					}
 
-					if(time_in_state > 1000 && power_state.vout_avg < MPP_VOLTAGE_THR) {
+					if(time_in_state > 1000 && power_state.vout_avg < VOLTAGE_THR_FLOAT_TO_MPP) {
+						pwm = CONV_PWM_MAX * 8 / 10;
 						operState = ConvMPP;
 					}
 
@@ -809,9 +898,6 @@ int main(void)
 						iErr = 0;
 					}
 
-					// bootstrap off
-					timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
-
 					// calculate error values
 					pErr = fxp_sub(MAX_CURRENT, power_state.current_avg);
 					iErr = fxp_add(iErr, pErr);
@@ -844,15 +930,12 @@ int main(void)
 						operState = ConvMPP;
 					}
 
-					if(power_state.vout_avg > MAX_VOLTAGE) {
+					if(power_state.vout_avg > MPP_MAX_VOLTAGE) {
 						operState = ConvConstVoltage;
 					}
 					break;
 
 				case ConvMPP:
-					// bootstrap off
-					timer_set_oc_value(TIM1, TIM_CH_BOOTSTRAP, 0);
-
 					mpp_run(time_in_state, &mpp_state, &power_state, &pwm);
 
 					if(pwm > mpp_state.mppMaxPWM) {
@@ -883,7 +966,7 @@ int main(void)
 						pwm = mpp_state.mppMaxPWM;
 					}
 
-					if(power_state.vout_avg > MAX_VOLTAGE) {
+					if(power_state.vout_avg > MPP_MAX_VOLTAGE) {
 						operState = ConvConstVoltage;
 					}
 
@@ -984,6 +1067,9 @@ int main(void)
 					case ConvConstVoltage:
 						lcd_send_string("CV ");
 						break;
+					case ConvFloat:
+						lcd_send_string("FLT");
+						break;
 					case ConvMPP:
 						lcd_send_string("MPP");
 						break;