More updates (#26)

* Overvoltage work

* Update firmware rev to 1.2

Author: AlexKlimaj

Inc/battery.h

@@ -20,9 +20,10 @@ extern "C" {
 #define VOLTAGE_CONNECTED_THRESHOLD			(uint32_t)( 0.1 * BATTERY_ADC_MULTIPLIER )
 #define CELL_DELTA_V_ENABLE_BALANCING		(uint32_t)( 0.015 * BATTERY_ADC_MULTIPLIER )
 #define CELL_BALANCING_HYSTERESIS_V			(uint32_t)( 0.010 * BATTERY_ADC_MULTIPLIER )
-#define CELL_BALANCING_SCALAR_MAX			(uint8_t)30
+#define CELL_BALANCING_SCALAR_MAX			(uint8_t)25
 #define MIN_CELL_V_FOR_BALANCING			(uint32_t)( 3.0 * BATTERY_ADC_MULTIPLIER )
 #define CELL_VOLTAGE_TO_ENABLE_CHARGING		(uint32_t)( 4.18 * BATTERY_ADC_MULTIPLIER )
+#define CELL_OVER_VOLTAGE_ENABLE_DISCHARGE	(uint32_t)( 4.205 * BATTERY_ADC_MULTIPLIER )
 #define CELL_OVER_VOLTAGE_DISABLE_CHARGING	(uint32_t)( 4.22 * BATTERY_ADC_MULTIPLIER )
 #define MIN_CELL_VOLTAGE_SAFE_LIMIT			(uint32_t)( 2.0 * BATTERY_ADC_MULTIPLIER )
 

Inc/bq25703a_regulator.h

@@ -90,7 +90,7 @@ extern "C" {
 #define IIN_ADC_SCALE				(uint32_t)(0.050 * REG_ADC_MULTIPLIER)
 
 #define MAX_CHARGE_CURRENT_MA		6000
-#define ASSUME_EFFICIENCY			0.9f
+#define ASSUME_EFFICIENCY			0.85f
 #define BATTERY_DISCONNECT_THRESH	(uint32_t)(4.215 * REG_ADC_MULTIPLIER)
 #define MAX_CHARGING_POWER			60000
 #define NON_USB_PD_CHARGE_POWER		2500

Inc/main.h

@@ -136,7 +136,7 @@ void Error_Handler(void);
 /* USER CODE BEGIN Private defines */
 
 #define LIPOW_MAJOR_VERION	(uint8_t)1
-#define LIPOW_MINOR_VERION	(uint8_t)1
+#define LIPOW_MINOR_VERION	(uint8_t)2
 
 /* USER CODE END Private defines */
 

Src/battery.c

@@ -51,9 +51,16 @@ void Balance_Battery()
 			}
 		}
 
+		float scalar = 0.0f;
+
 		// Scale the balancing thresholds tighter as the battery voltage increases. Allows for faster charging.
-		float scalar = (float)CELL_BALANCING_SCALAR_MAX * (1.0f - (((float)max_cell_voltage - (float)MIN_CELL_V_FOR_BALANCING)/((float)CELL_VOLTAGE_TO_ENABLE_CHARGING - (float)MIN_CELL_V_FOR_BALANCING)));
-		if (scalar < 1.0f) {
+		if (battery_state.xt60_connected == CONNECTED) {
+			scalar = (float)CELL_BALANCING_SCALAR_MAX * (1.0f - (((float)max_cell_voltage - (float)MIN_CELL_V_FOR_BALANCING)/((float)CELL_VOLTAGE_TO_ENABLE_CHARGING - (float)MIN_CELL_V_FOR_BALANCING)));
+			if (scalar < 1.0f) {
+				scalar = 1.0f;
+			}
+		}
+		else {
 			scalar = 1.0f;
 		}
 
@@ -64,21 +71,22 @@ void Balance_Battery()
 			battery_state.balancing_enabled = 0;
 		}
 
-		if (battery_state.balancing_enabled == 1) {
-
-			for(int i = 0; i < battery_state.number_of_cells; i++) {
-				if ( (Get_Cell_Voltage(i) - min_cell_voltage) >= ((float)CELL_BALANCING_HYSTERESIS_V * scalar)) {
-					battery_state.cell_balance_bitmask |= (1<<i);
-				}
-				else {
-					battery_state.cell_balance_bitmask &= ~(1<<i);
-				}
+		//Check each cell voltage. If XT60 is connected, then allow larger voltage differences that tighten as the battery voltage increases.
+		//If just the balance port is connected, then use the tightest balancing thresholds
+		//If a cell is over CELL_OVER_VOLTAGE_ENABLE_DISCHARGE, then the discharging resistor will turn on
+		for(int i = 0; i < battery_state.number_of_cells; i++) {
+			if ( (battery_state.balancing_enabled == 1) && ((Get_Cell_Voltage(i) - min_cell_voltage) >= ((float)CELL_BALANCING_HYSTERESIS_V * scalar))) {
+				battery_state.cell_balance_bitmask |= (1<<i);
+			}
+			else if (Get_Cell_Voltage(i) >= CELL_OVER_VOLTAGE_ENABLE_DISCHARGE) {
+				battery_state.cell_balance_bitmask |= (1<<i);
+			}
+			else {
+				battery_state.cell_balance_bitmask &= ~(1<<i);
 			}
-			Balancing_GPIO_Control(battery_state.cell_balance_bitmask);
-		}
-		else {
-			Balancing_GPIO_Control(0);
 		}
+		Balancing_GPIO_Control(battery_state.cell_balance_bitmask);
+
 	}
 	else {
 		Balancing_GPIO_Control(0);