basic drivetrain pretension implemented, read cfg not working

pretension speed cutoff configurable via GUI with units

small fixes and cleanup

double default speed for pretension feature for safety

fix compile error and pre-compute pretension cutoff speed in init

require use of speed sensor for pretension feature

update readme with new screenshot of config tool

fix line endings in app.c

fix line endings in Configuration.cs

fixed line endings in SystemView.xaml

README.md

@@ -42,7 +42,7 @@ If you find this project useful, consider sending a small [donation](https://www
 * ✅ Display motor/controller temperature on standard display.
 * ✅ Use of speed sensor is optional.
 
-![Config Tool](https://raw.githubusercontent.com/wiki/danielnilsson9/bbshd-fw/img/config_tool/config_tool3.png)
+![Config Tool](https://github.com/user-attachments/assets/1534c303-b25f-4fa4-8b37-5b74ade4a800)
 
 ## Supported Hardware
 

src/firmware/app.c

@@ -55,13 +55,16 @@ static int8_t temperature_motor_c;
 static uint16_t ramp_up_current_interval_ms;
 static uint32_t power_blocked_until_ms;
 
+static uint16_t pretension_cutoff_speed_rpm_x10;
+
 static bool lights_state = false;
 
 void apply_pas_cadence(uint8_t* target_current, uint8_t throttle_percent);
 #if HAS_TORQUE_SENSOR
 void apply_pas_torque(uint8_t* target_current);
 #endif
 
+void apply_pretension(uint8_t* target_current);
 void apply_cruise(uint8_t* target_current, uint8_t throttle_percent);
 bool apply_throttle(uint8_t* target_current, uint8_t throttle_percent);
 bool apply_speed_limit(uint8_t* target_current, uint8_t throttle_percent, bool pas_engaged, bool throttle_override);
@@ -107,6 +110,8 @@ void app_init()
 
 	speed_limit_ramp_interval_rpm_x10 = convert_wheel_speed_kph_to_rpm(SPEED_LIMIT_RAMP_DOWN_INTERVAL_KPH) * 10;
 
+	pretension_cutoff_speed_rpm_x10 = convert_wheel_speed_kph_to_rpm(g_config.pretension_speed_cutoff_kph) * 10;
+
 	cruise_paused = true;
 	operation_mode = OPERATION_MODE_DEFAULT;
 
@@ -139,6 +144,7 @@ void app_process()
 	}
 	else
 	{
+		apply_pretension(&target_current);
 		apply_pas_cadence(&target_current, throttle_percent);
 #if HAS_TORQUE_SENSOR
 		apply_pas_torque(&target_current);
@@ -352,6 +358,16 @@ uint8_t app_get_temperature()
 	return (uint8_t)temp_max;
 }
 
+void apply_pretension(uint8_t* target_current)
+{
+	uint16_t current_speed_rpm_x10 = speed_sensor_get_rpm_x10();
+
+	if (g_config.use_speed_sensor && g_config.use_pretension && current_speed_rpm_x10 > pretension_cutoff_speed_rpm_x10)
+	{
+		*target_current = 1;
+	}
+	return;
+}
 
 void apply_pas_cadence(uint8_t* target_current, uint8_t throttle_percent)
 {
@@ -919,7 +935,6 @@ void block_power_for(uint16_t ms)
 	power_blocked_until_ms = system_ms() + ms;
 }
 
-
 void reload_assist_params()
 {
 	if (assist_level < ASSIST_PUSH)

src/firmware/bbsx/motor.c

@@ -35,7 +35,6 @@
 
 #define READ_TIMEOUT			100
 
-
 #if defined(BBSHD)
 	#define ADC_STEPS_PER_AMP_X10		69
 	#define ADC_STEPS_PER_VOLT_X100		1490 // 1460 in orginal firmware
@@ -57,7 +56,6 @@
 
 #define MSGBUF_SIZE					8
 
-
 static uint8_t is_connected;
 static uint8_t msgbuf[MSGBUF_SIZE];
 
@@ -160,7 +158,6 @@ void motor_process()
 	process_com_state_machine();
 }
 
-
 void motor_enable()
 {
 	SET_PIN_HIGH(PIN_MOTOR_POWER_ENABLE);
@@ -262,8 +259,6 @@ uint16_t motor_get_battery_voltage_x10()
 	return battery_volt_x10;
 }
 
-
-
 static uint8_t compute_checksum(uint8_t* msg, uint8_t len)
 {
 	uint8_t checksum = 0;

src/firmware/cfgstore.c

@@ -26,7 +26,6 @@
 #define EEPROM_ERROR_ERASE			6
 #define EEPROM_ERROR_WRITE			7
 
-
 static const uint8_t default_current_limits[] = { 7, 10, 14, 19, 26, 36, 50, 70, 98 };
 
 #if HAS_TORQUE_SENSOR
@@ -163,6 +162,8 @@ static void load_default_config()
 	g_config.use_speed_sensor = 1;
 	g_config.use_shift_sensor = HAS_SHIFT_SENSOR_SUPPORT;
 	g_config.use_push_walk = 1;
+	g_config.use_pretension = 0;
+	g_config.pretension_speed_cutoff_kph = 16;
 	g_config.use_temperature_sensor = TEMPERATURE_SENSOR_CONTR | TEMPERATURE_SENSOR_MOTOR;
 
 	g_config.lights_mode = LIGHTS_MODE_DEFAULT;
@@ -215,7 +216,6 @@ static void load_default_config()
 	}
 }
 
-
 static bool read_pstate()
 {
 	eventlog_write(EVT_MSG_PSTATE_READ_BEGIN);
@@ -269,8 +269,6 @@ static void load_default_pstate()
 	g_pstate.adc_voltage_calibration_steps_x100_i16h = 0;
 }
 
-
-
 static uint8_t read(uint8_t page, uint8_t version, uint8_t* dst, uint8_t size)
 {
 	uint8_t read_offset = 0;

src/firmware/cfgstore.h

@@ -90,6 +90,8 @@ typedef struct
 	uint8_t use_push_walk;
 	uint8_t use_temperature_sensor;
 	uint8_t lights_mode;
+	uint8_t use_pretension;
+	uint8_t pretension_speed_cutoff_kph;
 
 	// speed sensor
 	uint8_t wheel_size_inch_x10_u16l;

src/tool/Model/Configuration.cs

@@ -18,7 +18,7 @@ public class Configuration
 		public const int ByteSizeV1 = 120;
 		public const int ByteSizeV2 = 124;
 		public const int ByteSizeV3 = 149;
-		public const int ByteSizeV4 = 152;
+		public const int ByteSizeV4 = 154;
 
 		public enum Feature
 		{
@@ -28,7 +28,6 @@ public enum Feature
 			MotorTemperatureSensor
 		}
 
-
 		public static int GetByteSize(int version)
 		{
 			switch (version)
@@ -109,7 +108,6 @@ public enum LightsModeOptions
 			BrakeLight = 3
 		}
 
-
 		public class AssistLevel
 		{
 			[XmlAttribute]
@@ -131,7 +129,6 @@ public class AssistLevel
 			public float TorqueAmplificationFactor;
 		}
 
-
 		[XmlIgnore]
 		public BbsfwConnection.Controller Target { get; private set; }
 
@@ -168,6 +165,8 @@ public uint MaxCurrentLimitAmps
 		public bool UseSpeedSensor;
 		public bool UseShiftSensor;
 		public bool UsePushWalk;
+		public bool UsePretension;
+		public uint PretensionSpeedCutoffKph;
 		public TemperatureSensor UseTemperatureSensor;
 
 		// lights
@@ -204,7 +203,6 @@ public uint MaxCurrentLimitAmps
 		public AssistLevel[] StandardAssistLevels = new AssistLevel[10];
 		public AssistLevel[] SportAssistLevels = new AssistLevel[10];
 
-
 		public Configuration() : this(BbsfwConnection.Controller.Unknown)
 		{ }
 
@@ -221,6 +219,8 @@ public Configuration(BbsfwConnection.Controller target)
 			UseSpeedSensor = false;
 			UseShiftSensor = false;
 			UsePushWalk = false;
+			UsePretension = false;
+			PretensionSpeedCutoffKph = 0;
 			UseTemperatureSensor = TemperatureSensor.All;
 
 			LightsMode = LightsModeOptions.Default;
@@ -345,6 +345,8 @@ public bool ParseFromBufferV1(byte[] buffer)
 			ShiftInterruptDuration = 600;
 			ShiftInterruptCurrentThresholdPercent = 10;
 			LightsMode = LightsModeOptions.Default;
+			UsePretension = false;
+			PretensionSpeedCutoffKph = 16;
 			ThrottleGlobalSpeedLimit = ThrottleGlobalSpeedLimitOptions.Disabled;
 			ThrottleGlobalSpeedLimitPercent = 100;
 
@@ -418,6 +420,8 @@ public bool ParseFromBufferV2(byte[] buffer)
 			ShiftInterruptDuration = 600;
 			ShiftInterruptCurrentThresholdPercent = 10;
 			LightsMode = LightsModeOptions.Default;
+			UsePretension = false;
+			PretensionSpeedCutoffKph = 16;
 			ThrottleGlobalSpeedLimit = ThrottleGlobalSpeedLimitOptions.Disabled;
 			ThrottleGlobalSpeedLimitPercent = 100;
 
@@ -446,6 +450,8 @@ public bool ParseFromBufferV3(byte[] buffer)
 				UseSpeedSensor = br.ReadBoolean();
 				UseShiftSensor = br.ReadBoolean();
 				UsePushWalk = br.ReadBoolean();
+				UsePretension = br.ReadBoolean();
+				PretensionSpeedCutoffKph = br.ReadByte();
 				UseTemperatureSensor = (TemperatureSensor)br.ReadByte();
 
 				WheelSizeInch = br.ReadUInt16() / 10f;
@@ -523,6 +529,9 @@ public bool ParseFromBufferV4(byte[] buffer)
 
 				LightsMode = (LightsModeOptions)br.ReadByte();
 
+				UsePretension = br.ReadBoolean();
+				PretensionSpeedCutoffKph = br.ReadByte();
+
 				WheelSizeInch = br.ReadUInt16() / 10f;
 				NumWheelSensorSignals = br.ReadByte();
 
@@ -569,7 +578,6 @@ public bool ParseFromBufferV4(byte[] buffer)
 			return true;
 		}
 
-
 		public byte[] WriteToBuffer()
 		{
 			using (var s = new MemoryStream())
@@ -591,6 +599,9 @@ public byte[] WriteToBuffer()
 
 				bw.Write((byte)LightsMode);
 
+				bw.Write(UsePretension);
+				bw.Write((byte)PretensionSpeedCutoffKph);
+
 				bw.Write((UInt16)(WheelSizeInch * 10));
 				bw.Write((byte)NumWheelSensorSignals);
 
@@ -649,6 +660,8 @@ public void CopyFrom(Configuration cfg)
 			UseSpeedSensor = cfg.UseSpeedSensor;
 			UseShiftSensor = cfg.UseShiftSensor;
 			UsePushWalk = cfg.UsePushWalk;
+			UsePretension = cfg.UsePretension;
+			PretensionSpeedCutoffKph = cfg.PretensionSpeedCutoffKph;
 			UseTemperatureSensor = cfg.UseTemperatureSensor;
 			LightsMode = cfg.LightsMode;
 			WheelSizeInch = cfg.WheelSizeInch;
@@ -721,6 +734,7 @@ public void Validate()
 			ValidateLimits((uint)WheelSizeInch, 10, 40, "Wheel Size (inch)");
 			ValidateLimits(NumWheelSensorSignals, 1, 10, "Wheel Sensor Signals");
 			ValidateLimits(MaxSpeedKph, 0, 180, "Max Speed (km/h)");
+			ValidateLimits(PretensionSpeedCutoffKph, 0, 100, "Pretension Speed Cutoff (km/h)");
 
 			ValidateLimits(PasStartDelayPulses, 0, 24, "Pas Delay (pulses)");
 			ValidateLimits(PasStopDelayMilliseconds, 50, 1000, "Pas Stop Delay (ms)");
@@ -756,14 +770,12 @@ public void Validate()
 			}
 		}
 
-
 		private void ValidateLimits(uint value, uint min, uint max, string name)
 		{
 			if (value < min || value > max)
 			{
 				throw new Exception(name + " must be in interval " + min + "-" + max + ".");
 			}
 		}
-
 	}
 }

src/tool/View/SystemView.xaml

@@ -197,6 +197,8 @@
 					<RowDefinition Height="Auto" />
 					<RowDefinition Height="Auto" />
 					<RowDefinition Height="Auto" />
+					<RowDefinition Height="Auto" />
+					<RowDefinition Height="Auto" />
 				</Grid.RowDefinitions>
 
 				<TextBlock Grid.Row="0" Text="Features" FontSize="18" FontWeight="Bold" />
@@ -239,6 +241,40 @@
 					</TextBlock.ToolTip>
 				</TextBlock>
 				<ComboBox Grid.Column="2" Grid.Row="5" Margin="0 8 0 0" Padding="6 2 6 0" Width="100" Height="20" HorizontalAlignment="Right" ItemsSource="{Binding ConfigVm.LightsModeOptions}" SelectedItem="{Binding ConfigVm.LightsMode, UpdateSourceTrigger=PropertyChanged}" />
+
+				<TextBlock Grid.Column="0" Grid.Row="6" Margin="0 8 0 0" Text="Pretension Mode:">
+					<TextBlock.ToolTip>
+						<TextBlock Width="300" TextWrapping="Wrap">
+							Apply 1% of Max Current when above a threshold road speed to pre-tension the drivetrain.
+							This makes it nicer for more aggressive PAS / throttle settings since freewheel pawls
+							will not get smacked if there is play in the drivetrain system.
+						</TextBlock>
+					</TextBlock.ToolTip>
+				</TextBlock>
+				<CheckBox Grid.Column="2" Grid.Row="6" Margin="0 8 0 0" HorizontalAlignment="Right"  IsChecked="{Binding ConfigVm.UsePretension, UpdateSourceTrigger=PropertyChanged}" IsEnabled="{Binding ConfigVm.UseSpeedSensor}" />
+
+				<TextBlock Grid.Column="0" Grid.Row="7" Margin="0 10 0 0" Text="Pretension Speed Cutoff (km/h):" Visibility="{Binding ConfigVm.UseMetricUnits, Converter={StaticResource BoolToVis}}">
+					<TextBlock.ToolTip>
+						<TextBlock Width="300" TextWrapping="Wrap">
+							Pretension will not be applied at and below this roadspeed. Take caution setting this to zero, as
+							your bike will roll forward as soon as it is powered on and pushed. Recommended to start with ~16kph
+							and lower if necessary once comfortable with the feature.
+					</TextBlock>
+				</TextBlock.ToolTip>
+				</TextBlock>
+				<TextBox Grid.Column="2" Grid.Row="7" Margin="0 10 0 0" Width="60" HorizontalAlignment="Right" Text="{Binding ConfigVm.PretensionSpeedCutoffKph, UpdateSourceTrigger=PropertyChanged}" Visibility="{Binding ConfigVm.UseMetricUnits, Converter={StaticResource BoolToVis}}" IsEnabled="{Binding ConfigVm.UseSpeedSensor}" />
+
+				<TextBlock Grid.Column="0" Grid.Row="7" Margin="0 10 0 0" Text="Pretension Speed Cutoff (mph):" Visibility="{Binding ConfigVm.UseImperialUnits, Converter={StaticResource BoolToVis}}" >
+					<TextBlock.ToolTip>
+						<TextBlock Width="300" TextWrapping="Wrap">
+							Pretension will not be applied at and below this roadspeed. Take caution setting this to zero, as
+							your bike will roll forward as soon as it is powered on and pushed. Recommended to start with ~10mph
+							and lower if necessary once comfortable with the feature.
+					</TextBlock>
+				</TextBlock.ToolTip>
+				</TextBlock>
+				<TextBox Grid.Column="2" Grid.Row="7" Margin="0 10 0 0" Width="60" HorizontalAlignment="Right" Text="{Binding ConfigVm.PretensionSpeedCutoffMph, UpdateSourceTrigger=PropertyChanged}" Visibility="{Binding ConfigVm.UseImperialUnits, Converter={StaticResource BoolToVis}}" IsEnabled="{Binding ConfigVm.UseSpeedSensor}" />
+
 			</Grid>
 
 			<Grid Margin="0 20 0 0">
@@ -323,7 +359,6 @@
 					<RowDefinition Height="Auto" />
 				</Grid.RowDefinitions>
 
-
 				<TextBlock Grid.Row="0" Text="Miscellaneous" FontSize="18" FontWeight="Bold" />
 
 				<TextBlock Grid.Column="0" Grid.Row="1" Margin="0 10 0 0" Text="Walk Mode Data Display:">

src/tool/ViewModel/Base/DelegateCommand.cs

@@ -10,7 +10,6 @@ public class DelegateCommand : ICommand
 
 		public event EventHandler CanExecuteChanged;
 
-
 		public DelegateCommand(Action action)
 		{
 			_action = action;
@@ -23,8 +22,6 @@ public DelegateCommand(Action<object> action)
 			_action = null;
 		}
 
-
-
 		public bool CanExecute(object parameter)
 		{
 			return true;